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Direct-Hit Power User Monthly – April 2019

Bookmark For Saving Documents & Diagrams.

Bookmarks are the best way to save your progress in Direct-Hit. If you need to step away from a job you can use bookmarks to return instantly to all the documents and diagrams you were using earlier.


Bookmarking is a Huge Time-Saver in Direct-Hit

The Bookmark feature lets you save as many documents as you want or need.

  • Hotline Archives – You can bookmark them
  • Wiring Diagrams – You can bookmark them
  • Remove and Replace Procedures – You know they’re bookmarkable
  • Anything else in Direct-Hit… You guessed it


Using Bookmarks

On every page, you will find a menu in the right-hand corner with a button named “Bookmark.” This button will save the page/document you are currently viewing.

To find your bookmarksnavigate to the home screen (click Home in the upper left corner). 

On the main screen in the upper right-hand corner of the top navigation menu, you’ll find an option named “Bookmarks.” Clicking this will take you to all of the pages you have saved for the vehicle you are working on.

Quick reminder: You need to have the same vehicle open in Direct-Hit to find the bookmarks you saved for it.

You can tell which vehicles have bookmarks by looking for the bookmark symbol next to the vehicle name. 


It’s that Simple

Now you can step away and be able to come right back to where you left off. 
You can also find this information in the Training Toolbox found in the lower right-hand corner of Direct-Hit. 


Looking to learn even more power user tips and tricks for Direct-Hit? Register for a free training webinar.


Fix of The Week 4/12/19

Fix of the week


Fix of The Week

Every week we’re posting our favorite head-scratchers and interesting mechanical issues submitted by our Direct-Hit customers.

For a chance to have something you’ve worked on appear as a Fix of the Week, and win a cool little prize for your shop, all you have to do is post your unique fixes in Direct-Hit. Just look up the vehicle you’re working on, click on Post Fix at the top right, then tell us the problem and what you did to fix it.


This Week’s Winners

On this edition of Fix of The Week: sensors out of spec in a Nissan, a sticky window in a Honda, and another with a finicky immobilizer.


2006 Nissan Titan – Sacto Auto Repair

This customer had replaced both the camshaft and crankshaft sensor using aftermarket parts. They reset the check engine but it would turn back on after 1 drive cycle. The RPM fluttered and there was extended cranking. We tested the resistance of both sensors—those were within spec. We also checked the voltage to the sensors and suspected the problem was with the cam and crank sensor being out of spec once the vehicle was within normal operating temperature. We replaced with OEM HITACHI sensors. We drove the vehicle twice to verify the concern was corrected and the RPM gauge no longer flutters and check engine light stayed off.  


2004 Honda Pilot – Plymouth Village Automotive

The customer came in because her vehicle’s right rear window was stuck down. When trying to command the window up with the master switch, the door locks would activate. The intermittent battery light and warning lights in the dash came on while driving. We removed the passenger multiplex module at the right kick panel to check powers and grounds. The module was wet with water. The customer stated she got a car wash before the problem started and a new windshield was installed 3 months prior, which was leaking. We dried out the module and the window works properly again.


2006 Pontiac G6 – TGK Automotive

We performed an oil change on this Honda and cleared the P0420 code for the customer at their request. The vehicle would not start, and the immobilizer green key light would not light up—ever. There was no spark and no injector pulse. The starter worked fine and all communication was fine except the immobilizer, which both scan tools said was not equipped on this vehicle. That had us scratching our heads.  

There were no codes in any module and the launch torque and Snap-On Modis ultra were both fully updated. We tore the steering column clamshell cover off and tested for powers and grounds at the immobilizer plugs, all of which tested good. With the key on, we unplugged both connectors for 10 seconds. Upon plugging back in, the immobilizer light came on and flashed a few times then went out. The car starts fine now, and we’re guessing the immobilizer needed to be reset from clearing codes.

Find these and 2 million other confirmed fixes in Direct-Hit. Get a 14 day test-drive for just $1.00


Battery Drain Testing

Battery Drain Testing 

Let’s talk about the infamous battery drain. Every shop has seen it and worked on it, but not every shop is as successful as it should beThe days of connecting the test light between the battery cable and battery post while pulling fuses are gone. Now you have to worry about Controller Area Network (CAN) buses

In this article, we will reference several TSBs, be sure to grab them here. There will also be a link at the end of the article. 

CAN Buses 

CAN buses are data lines used to connect every computer and component in the car together. Take a dome light for an exampleit’s now turned on by a computerThat computer is connected to a network that is connected to another computer set up to watch for a switch input. If any computer connected to the network decides to send information, you get a battery drainIs the drain caused by the computer connected to the light, switch, or some other computer on the network? A little too complex for a dome light if you ask me.   

Finding the Battery Drain 

Today’s complex cars have different strategies that can either help or hinder the process of tracking down a battery drain. Computer-controlled battery disconnect relays designed to disconnect fuse boxes based on inputs from battery monitoring sensors and computers can potentially hide a drain. How do you find a drain on a car that has a hidden drain? You need the right tools to dig into a battery drain with confidence. Some of those tools you may already haveothers may be far from sensible to purchase. In either case, a test light is not one of them. 

Some Tools You’ll Need    

Some of the tools that will help in diagnosis start with a quality Digital Volt Ohm Meter (DVOM) that reads millivolts and milliamps. Be aware that in some cases it saves time to have twoAt the higher end, when there is evidence of a difficult diagnosis, you may need a compatible scan tool and oscilloscope. By far the most important tool will be access to an information system like Direct-Hit that has service bulletins, wiring diagrams, component locations, and repair information on your vehicle.   


Diagnosing the Drain 

To start your diagnosis, you first need to talk to the customer and get some history: important notes like how often the battery goes dead and when. There can be special circumstances that may lead your diagnosis to a quicker repairfor instance, the battery drain only occurs after removing groceries from the trunk. That may direct you to a sticking trunk release switch or trunk ajar switch. Another step you can take to help speed up your diagnosis is to use your scan tool to perform a complete scan of the car. Look for the smoking gun such as fault codes that state switches are stuck on or that there is a faulty alarm siren. 

Once you have your information, be sure to have a known good battery that maintains 12.6 volts installed. If its low on charge, it may complicate your diagnosis. Swap the customers battery with a fully charged battery if needed. Next you’lneed to set up the car for testing. This would include gaining access to all the fuse boxes before you start testing. Open all doors, hood, and trunk while closing all respective latches or manipulate ajar switches to simulate the vehicle is closed. Lock the car and wait. Wait times can differ from car to car but use the general rule of at least 45 minutes 

Manufacturer Test Procedures 

Most manufacturers test procedures will indicate different specifications for what they consider is an acceptable drain. We like to keep readings under .050 amps or 50 milliamps. When connecting your ammeter, we would recommend using a quality ammeter clamp that correctly reads milliamps. Without a clamp, you need to be careful not to break the circuit when installing your meter in series. This means connect your ammeter positive lead to the negative battery cable and connect the ammeter negative lead to the negative battery post. Then disconnect the battery cable from the battery. Failure to do this will blow the fuse in your meter once the car’s alarm goes ofand you’ll have to wait another 45 minutes. 

Choosing the Right Tools 

Now that youve identified a battery drain exists, it’s time to get your tools in order. On your toolbox you have Direct-Hit set up with fuse locations and wiring diagrams displayedNext to that is your second DVOM ready to do testing. You’ve got your tools in hand, but now what? The actual amount of drain can lead you to some clues as to which direction to takeA large drain, say over 2 amps, can be caused by a load carrying component such as a light, alternator, or blower motor running. A small drain, less than 2 amps, can be caused by a CAN bus drain due to computers failing to enter sleep mode. 


Using Service Bulletins 

A lot of manufacturers have published bulletins such as this one from Mercedes: S-B-54.10/162It describes how to test the voltage drop across fuses to determine which circuit is causing the drain. Mercedes even requires this in their service information, as noted in example document AR54.10-p-1030-09GZNotice we did not say remove the fuses one at a time. This is not a process that works well for modern cars. There is too much going on that will lead you down a long endless diagnosis if you pull fuses out and put them back in. Its been found that even after just one fuse is removed, you have to wait at least 5 minutes to see if it did anything. With hundreds of fuses in cars, you can see that’s a big chunk of time. 

With the help of service bulletins, you can identify how much current is going through each fuse. Grab a pen and paper and record the highest voltage drop and its location. Continue testing all fuses until you find the largest one. Only after identifying what that fuse does on a wiring diagram will we remove the fuse, or the component connected to the fuse and retest for repair verification. Its a good idea to identify the fuses that have voltage drops on them in more than one way. If you have a voltage drop on a fuse that is only supposed to be powered after the key is on, that will give you a clue to use the diagrams and find out why it has voltage when its not supposed to have voltage on it.  

Direct-Hit gives you access to thousands of OEM Tech Service Bulletins searchable by manufacturer, vehicle, and symptom. 


CAN Bus Drains 

When dealing with CAN bus drains, the process becomes a little more difficult. Not only will your battery drain indicate this, but you may notice during your voltage drop testing that there are a dozen or more fuses that have noticeable voltage drops on them. You’ll need access to the manufacturernetwork diagrams. These diagrams will show you how many different networks are, and they’ll also give you ideas for good locations that you can use to easily monitor the network activity. This could be at the OBD data link connector, bus comb, or an easy to access module such as a seat control unit. The idea is to identify what network is “awake. Awake means that computers are continuing to communicate due to them not seeing a “sleep” message on the network. In these cases, every computer is pulling amps and that is why multiple fuses are showing small voltage drops.   

What you will notice on your network is CAN high and CAN low wires will show voltage. This can be done with a scope that shows activity or with a DVOM that reads the voltage. A scope is quicker for identifying activity as you either see digital square waves or not. A DVOM will require you to know what the awake voltage is and what the sleep voltage is. Our example is a body network on a Mercedes. When the bus is “awake” or when there is activity that would cause a CAN bus battery drain, you would have a voltage of around 0.65 volts on the high wire and a voltage of around 4.5 volts on the low wire. If the bus is “asleep” or there is no activity, you would notice voltages of 0.1 volts at the high and around battery voltage on the low. Use your information iDirect-Hit to locate every control unit and its fuse located on the network youre working on. One at a time, remove that control unit or its fuse, then wait 5 minutes before continuing. Do not reconnect the control unit or install the fuse. Doing so may restart your wait time of 45 minutes.   

A few Other Things to Consider

The diagnostic test steps provided are the new normal when it comes to finding battery drains. But wait, theres more. Remember that cars have battery sensors and disconnect relays? And that having a compatible scan tool is crucial to your diagnosisThe reasoning behind that is some manufacturers build in battery drain diagnosis into their cars and scan tools. Again, let’s use Mercedes as an example. They have an excellent service bulletin LI54.10-P-051559 where Mercedes has laid out a test program for locating battery drains. In that test program, there are specific scan tool instructions used to read battery drain data along with their own flow chart.   

With modern cars having several networks, you can see the complexity in locating the source of your drain along with the large amounts of time that may be required. The future of diagnosing battery drains is going to depend a lot on scan tool functions. The new factory equipment has software that turns the scan tool into a CAN bus analyzerMercedes calls this Keep-Alive Monitoring when using their Xentry CAN-Tool software. To summarize how that works, the scan tool will be connected to either the data link connector or to the network wiring. When connected, it records network communication in a manner that will display what control unit or control unit signal that is active in the order of first to lastThis is a game changer when it comes to network battery drains. No more setting up ammeters or testing dozens of fuses one at a time.    

Click here to download the TSBs we used in this article



Fix of The Week 04/5/19

Fix of the week


Fix of The Week

Every week we’re posting our favorite head-scratchers and interesting mechanical issues submitted by our Direct-Hit customers.

For a chance to have something you’ve worked on appear as a Fix of the Week, and win a cool little prize for your shop, all you have to do is post your unique fixes in Direct-Hit. Just look up the vehicle you’re working on, click on Post Fix at the top right, then tell us the problem and what you did to fix it.


This Week’s Winners

On this edition of Fix of The Week: a programming bug in a Honda, a Toyota running rough, and a wonky transmission in a Pontiac.


2016 Honda Civic – Double A Automotive

The customer returned the day after a tire replacement stating that the TPMS resent light was still on. We performed the reset again, drove 30 minutes at 49mph, turned the vehicle off, and waited 45 seconds. The TPMS light did not flash, indicating it had accepted the calibration. The customer returned the next day due to TPMs low tire warning again, so we called Honda to get some insight. They have a known programming flaw you have to calibrate 3 times in a row to clear any previous data. We performed the reset 3 times in rapid succession and since then the customer has not had to come back. A little tip: turn the key on to see if the calibration is accepted. After 45 seconds, the TPMS light will illuminate if it’s not.  


2004 Toyota RAV4 – Grandma’s Garage

This RAV4 was idling rough when the AC clutch was engaged and when the car was in drive or reverse. The idle drops to 400-500rmp and felt like it was about to stall out. The alternator voltage dropped to 12.5v. In addition, the battery was 4 years old and failed the load test and the alternator was draining. We checked for codes but found none, so we changed battery and alternator. At this point, there was no drain and the battery passed the load test, but we still had the issue with the idle drop when the AC clutch engaged. We hooked up the scan tool to check the MAF reading when the idle dropped, but that didn’t change. We removed the MAF which was filthy. We cleaned the MAF and throttle body and that fixed it.


2006 Pontiac G6 – TGK Automotive

The car moved in reverse fine but would not move in any forward gear positions. The transmission pan was removed to inspect the condition of the Forward Clutch, Low, and Reverse Band metal fluid/lube pipelines that sit just above the filter. The Lube/fluid pipeline assembly was replaced along with a new filter, pan gasket, and fluid. A test drive confirmed the transmission worked correctly.


Find these and 2 million other confirmed fixes in Direct-Hit. Get a 14 day test-drive for just $1.00

Meet Brian Franta



Mercedes Benz Master Certified Technician, ASE Master, ASE L1 Certified Technician.


Brian’s Experience

Brian Fanta has been managing the European carline team for the past 2 years but his automotive career began in 1994 at the Dunwoody Institute in Minneapolis, MN. He enrolled in a 2-year program in automotive technology while working at Sears automotive at night. Though the schedule was tough, the combination of formal training and hands-on experience helped him learn at a rapid rate.

Once he graduated, Brian went to work for a Ford/Lincoln/Mercury dealership as a general line technician. After five years, he took an opportunity to move to a Mercedes Benz dealership. There he worked on all areas of the car from heavy line to diagnostics for the next 6 1/2 years.


Joining Identifix

Eventually, Brian became interested in doing more than hands-on repair and found himself with the opportunity to work as a diagnostician for Identifix. Brian joined the European section of the Virtual Tech team in 2008 and initially focused on Mercedes Benz, 10 years on, he’s added all European manufacturers to his wheelhouse. Finally, in 2017, Brian took over the management of the European team where he leads by examples, providing top notch service to every caller and adding high-quality fixes to the Direct-Hit archive.


When He’s Not Working

When Brian isn’t helping diagnose and repair every European vehicle under the sun, he likes to go snowmobiling, ice fishing, and hunting. Over the summer, months he enjoys camping with his wife and two daughters.



Fix of The Week 03/29/19

Fix of the week


Fix of The Week

Every week we’re posting our favorite head-scratchers and interesting mechanical issues submitted by our Direct-Hit customers.

For a chance to have something you’ve worked on appear as a Fix of the Week, and win a cool little prize for your shop, all you have to do is post your unique fixes in Direct-Hit. Just look up the vehicle you’re working on, click on Post Fix at the top right, then tell us the problem and what you did to fix it.


This Week’s Winners

On this edition of Fix of The Week: loss of low beams in a Subarua stalling Toyota, and an incomplete tone ring in a Buick.


2007 Subaru Outback – Meineke Car Care Center

This vehicle came into the shop with no tail lights, no high or low headlights, no dome, no rear wiper or defroster. After performing the wiring repair, it still had no headlights. All the headlight bulbs had power on both pins and occasionally the high beams would turn on with the parking lights and random flickers of the low beams, but there was still no consistent low beam activity. 
We found almost every wire in the hatch hinges had broken and a few had melted together. We also found multiple blown fuses under the dash. Due to the symptoms, it was easy to get a bead on the malfunction. There are 2 loom sections in the hatch: one on the right for all major components and the left side has some grounds and the washer fluid hose. There were broken wires in both sides. When this happens, you want to thoroughly check all fuses. We only found fuses blown in the left passenger compartment fuse box, so we repaired the wiring, replaced fuse 23 and 18 under the left side dash. Afterward, there were no relay issues found.  


2005 Toyota 4Runner – San Juan Shell Service

This vehicle would idle without any problems, but upon driving it would cut out and stall. Code present was p0335. We tested the CKP sensor found within the specs. A good test is to wave at the sensor until it stalls and then flatlines. We removed the wire harness from CKP sensor and opened the wire loom where we found damaged wires from previous timing belt job. The wire harness was routed incorrectly and pinched between the A/C compressor and the mount for the compressor. We cut out the bad wires and made the fix.


2012 Buick LaCrosse  Atherton Automotive

This vehicle displayed ABS, Traction Control, and Service Brake Assist messages – code C0035.  
While watching the left front wheel speed with the scan tool, we noticed the speed was dropping out. We lifted the vehicle and inspected the wiring harness but didn’t find any issues. We attempted to see the back side of the wheel bearing for any issue and there was too much dirt build up, so we installed lab scope and measured the voltage drop across the sensor. While in drive, there was a repeated consistent missing of tone wheel square wave. We removed the wheel bearing and found the tone ring was missing a piece. We replaced the wheel bearing assembly and the vehicle now runs fine.


Find these and 2 million other confirmed fixes in Direct-Hit. Get a 14 day test-drive for just $1.00


Working on Hybrids Safely

This article is part two in our series about the electrification of the auto industry. We’re talking about electric vehicles, their history, how they work, how to service them, and what the trend towards more electric vehicles means for our industry. Click here for the first article in this series. Click here for the third article in the series.


Hybrid Vehicles

Seen any hybrids around lately? The ones with big old batteries in ‘em, don’t make the vroom vroom noises like a car should? Yes, you have. Hybrids are everywhere. Look out your window and you’d probably see a whole slew of them. There’s a Prius over there, an Escape hybrid there, a Leaf, a Volt, and a BMW I3. Nope, sorry, that’s a pack of AA batteries taped to a deck of cards…close enough. Hybrids, plug-in hybrids, and fully electric vehicles (EV) are here to stay and we need to accept that.

In 2017, nearly 3.8 million hybrid/EV vehicles were sold worldwide. Take a look at the chart below, which shows hybrid/EV vehicles sales across different countries for the last several years.

Electric Vehicle Sales

Domestically, hybrids and EVs are no slouch in the market either.

You may be asking, “Why should I care?”

Do you plan on wrenching for the foreseeable future? Do you like to have a heart that beats in the diastolic/systolic cardiac cycle? If you answered yes to either question, then it’s time to learn some of the basics of hybrids/EV vehicles to keep yourself safe and turn a buck while you’re at it.


Hybrid Vehicle Basics

Let’s start by talking about what a hybrid is; keep in mind that EVs are essentially the same, minus the gasoline engine. A hybrid vehicle consists of a large DC battery, a large 3-phase electric motor or two, an inverter, a DC-DC converter, and a gasoline engine which is usually referred to as an ICE (Internal Combustion Engine). For specific examples in this article, we’ll be referencing one of the most common hybrids, the Toyota Prius. Other hybrids have a very similar generic setup—consult service manuals when it’s time to put wrench to vehicle. See the example diagram here.

Hybrid Batteries

Let’s start from the back. Usually, hybrids keep their large batteries back there, which can range anywhere from 140-340 volts, depending on the vehicle. EV vehicles are going to have higher voltage, but rest assured, 140-340V is enough to stop anyone’s heart. EVs typically house their big batteries in the floor. The hybrid battery sends out DC voltage to a unit called the Inverter, but before it does this, there are several large relays called “Contactors” that must shut first. These Contactors are closed by a smaller 12v battery—this is how a hybrid uses low voltage to activate high voltage. The hybrid battery has a means of interrupting voltage flow for service, usually called the “Service Grip Plug” or “High Voltage Shut Off,” and can be in the form of a removable plug or a switch. Always check your service manual for the vehicle you’re working on.

When the high voltage leaves the battery, it does this on two large orange cables—orange because that’s the color that denotes lethal voltage. If you see orange on a hybrid, you know to be wary. One cable is positive, the other is negative. The high voltage system is totally enclosed and does not ground through the chassis. These two cables go into the Inverter, whose job it is to turn the DC voltage from the battery into AC voltage that the 3-phase hybrid motors can use.

Hybrid Motors

From the Inverter, there are 3 cables leaving for each hybrid motor. A Honda Civic hybrid has one motor between the engine and the transmission. A Toyota Prius has a setup like the one in the diagram above, one motor (MG1) is attached to the ICE and the other motor (MG2) is attached to the wheels. They’re called MG1 and 2 because they’re actually Motor/Generators—they regenerate voltage when the vehicle is slowing down, a hallmark of hybrid vehicles. These two motors are connected in the middle with something called the Power Split Device (PSD), a small bit of engineering that puts the Prius head and shoulders above the competition, in my opinion. Other vehicles, like those made by GM and Hyundai, have motors that help run the engine via a very tight serpentine belt.

The hybrid motors themselves are just large electrical stators with permanent magnet rotors in the middle. Think of a huge alternator and you get the idea.

There are a couple more pieces to the hybrid puzzle that aren’t depicted in the diagram above. There’s a battery ECU, which watches the battery voltage and temperature; a cooling system to help cool off the battery, usually a very small cooling fan; a hybrid vehicle ECU, whose job it is to decide how much work each motor does and whether or not it should charge or discharge; there’s also a DC-DC converter. You have high voltage from the hybrid battery, and one or two very large motor/generators to charge it with, but what about the 12v battery? It would be an exercise in poor judgment to have an alternator on a vehicle like this. The DC-DC converter steps down the high voltage into something the 12v battery can use (think of the DC-DC converter as a high-low solid state alternator).


Hybrid Service Tools

Before you jump in, let’s cover the safety equipment you should invest in. Don’t skimp on this stuff! The human body ranges from about 1,230 ohms to 3,000 ohms, depending on how big you are and how much Gatorade you have in you. That means that if you close a 125V circuit with yourself, you can get anywhere from 42-102mA of current running through you. It might not sound like a lot, but respiratory paralysis occurs between 30-70mA. Since 125V is about the weakest hybrid you’re likely to encounter, I would keep safety equipment nearby.

We’ll start with gloves. Class 0 gloves are highly recommended and come with a 1000v rating. Over these, you’ll strap on another pair of leather gloves. The rubber protects you and the leather protects the rubber from all the sharp metal bits you might be working around. You can find them at most retail stores—we recommend the Salisbury gloves from Grainger. Your gloves must be inspected and certified for use every 6 months and you should also inspect them yourself when you use them: roll up the cuff to inflate the glove and look for leaks. If it leaks, get another set.

Next up, DMM. A digital volt/ohm meter has to be up to the challenge of potentially high voltage work. The recommended rating for meters and leads is CAT3 @1000V. If you’re in the market for a capable meter, we recommend you also get one that has the “Insulation Test” function, which we’ll cover later. Here is the one we use, the Fluke 1587 Multimeter and Insulation Tester.

Now on to hand tools. There are a lot of insulated hand tools—they look like regular tools that have been dipped in a rubberized coating. Beware: these tools are not cheap, but your life is not cheap either. Focus on collecting what you need—a ratchet, 10mm socket, 12mm socket, flat head, and Philips screwdriver should get you started.

Diagnostic Equipment

Some more specialized diagnostic equipment you may consider would be the Milli-ohm meter. The stators for the hybrid motors on these vehicles are very precise, so precise that the ohm meter on your Fluke isn’t going to pass muster. Enter the Milli-ohm meter. This tool can tell you the resistance of the hybrid motor stators and can also tell you how long a wire is based on its resistance. For example, if you test between a wire and chassis ground and the reading indicates the wire length is 6 inches, then you know you’re looking for a short to ground approximately 6 inches from the connector. Very handy to have around.

Ready To Start

Now that you have an idea of what you’re looking at when one of these electric razors pulls into your stall, and you have all your safety equipment, you’re ready to start work right? Not yet. Always make sure you have verified that high voltage is gone before touching anything, and always assume anything orange on the vehicle has high voltage going through it. In order to start work, you must disconnect the 12v battery, then disable the high voltage system by either pulling the service plug or flipping a switch, put your DMM across the 12v battery to verify it works, then check across whatever component you’re working on to confirm it is inert. Finally, check across the 12v battery again to make sure your meter hasn’t died since you checked it last. This might seem tedious, but cardiac arrest is a much bigger hassle. Happy wrenching!

How to Diagnose Hybrid Vehicles

How to Diagnose Hybrid Vehicles

This article is part three in our series about the electrification of the auto industry. We’re talking about electric vehicles, their history, how they work, how to service them, and what the trend towards more electric vehicles means for our industry. Click here for the first article in this series. Click here for the second article in the series.

Diagnosing Hybrids

Working on a hybrid vehicle can range anywhere from confusing to plain dangerous if you don’t know what you’re doing. It’s important to have a basic understanding of the vehicle you’re working on as well as the tools you need to keep yourself safe. 


One of the most common failures in hybrids, likely no surprise to anyone reading this, is the battery. Although, it may not be the battery you’re thinking. The lowly 12v battery is the guy that has to start the party from the word “Go.” It’s the 12v battery’s job to wake up the hybrid vehicle ECU and shut the hybrid battery contactors. It’s very easy to overlook the health of the 12v battery since you don’t get the typical “slow crank” complaint of a dying battery in a non-hybrid vehicle. It works perfectly fine until it doesn’t.

The hybrid vehicle ECU has a lot of thinking to do right away when it wakes up, and it’s very picky about the order and speed with which the hybrid battery contactors operate. This is a big job for the 12v battery, which is intentionally small to keep the vehicle from being too heavy. If you find yourself chasing odd contactor codes, or you have a Prius that won’t “Ready On” properly, which is the Prius version of KOER, make sure the 12v battery connections are clean and tight and the 12v battery is in good shape.

Car Battery

Another quick note on 12v batteries—most of the time these are not the usual flooded acid batteries you may be used to. You’re more likely dealing with an Absorbed Glass Mat battery or AGM battery. Hybrid manufacturers (Toyota mainly) are very fond of putting the 12v battery inside the car. Why? No idea. AGM batteries don’t off-gas as badly as flooded batteries—if you find a battery mounted inside the car, odds are it’s AGM. AGM batteries can’t handle the aggressive charging that normal batteries can and you have to use a special charger set to AGM mode, or you’ll cook the expensive battery. If you don’t have an AGM mode, then just go low and slow with your charger.

More Batteries

The battery you imagined is most likely the hybrid battery. And no matter the vehicle, these batteries wear out from a single day of use. The most typical battery you’ll find is Nickel Metal Hydride or NiMH. These batteries are all put together in series to boost the voltage. Here is a look at a Prius Battery module—you can see that it has 6 cells, at a theoretical 0% State of Charge (SOC) the cell has 1V, at a theoretical 100% SOC the cell has 1.5V. You will realistically never see them hang around near 1V, and under regenerative braking, they can sometimes exceed the 1.5V for a short period of time. This module is used for Prius Gen 2 and 3. Gen 1 is very similar.

Hybrid Battery Cell

Here is an example of a battery module from a Honda Civic Hybrid. Honda went with the stick instead of the prismatic rectangle, but it functions very nearly the same.

Hybrid Batter Module

Note that two sticks are present in this picture and each stick has 6 cells.

In the Data list, you’ll see the terminology “Battery Block” for Toyota, and “Battery Module” for Honda. This is the voltage reading that the battery ECU is seeing from two of these rectangular or stick modules in series. Let’s do the math. Two modules in series equal 12 cells. Cells have a total range of 1-1.5v, so the data should show a total range of 12-18v. You’ll also see SOC, or State of Charge, and Total Battery Voltage. These are all good things to watch when you have a DTC for a battery issue, maybe a P0A7F – Hybrid Battery Deteriorated. There are some additional tools out there that can help you with this as well.

There is no “known good” voltage for these battery block PIDs. Suffice it to say that the hybrid vehicle ECU doesn’t want to get to 0% or to 100% charge, and that’s not healthy for the battery. Instead, it wants to maintain between 40-70% as best it can, with a real range of 20-80%. The important thing is that your battery blocks do not wander away from one another. If you see one block is at 13v and another is at 14v, that’s a problem. Electrons are not flowing as well through one block as the other. The range of difference that is tolerable depends on the model, but around .2v is fine if you’re beating the battery up—anything more than .5v difference is an issue.


Check out some of the data PIDs below.


If you have some modules wandering away from one another during testing, then either the battery is genuinely failing (most likely) or the module that watches the battery voltage is drunk at the wheel (less likely). In many cases, by the time you get your hands on a vehicle, someone else has already worked on it, and they’ve hung a battery replacement on it along with a nice warning sticker that says “Do not open case, warranty is void if seal is broken.” If you see one of these, stop immediately, assess the nature of the warranty and then get a new battery from whoever owes it to the customer.

If the battery has not been replaced and data stream shows wandering voltage, then it’s time to dig into the battery case. On a Prius, there are several visual clues that can lead to the replacement of the battery. Disable the high voltage circuit, then take the top of the battery case off and look at all the battery blocks—if you see any that are weeping a clear or blue liquid, this is electrolyte from the battery cells. The electrolyte in a Prius battery is COH (Potassium Hydroxide) and when it leaks out, it’s as conductive as a pool of liquid copper, so be careful when you see it.

Hybrid Battery Block

Another element to remember is the “bus bar,” the long row of washers and nuts in the orange case. Keep an eye on the negative terminal for corrosion—this is pandemic for Priuses.

If the battery pack is OK via visual inspection, you may need to confirm the voltage difference with a voltmeter (see the “Hybrid Vehicle Safety and Basics” article for meter specs). Be very careful when working with a live battery exposed for testing.

When you confirm a bad battery, there are several options available to you. First is you can go OE and get a battery from the dealer, which is not a cheap option. You will, however, get the highest quality battery that money can buy. Second, you can buy an after-market remanufactured battery. This option is likely to save you some money but at the cost of some quality. The outfits that “rebuild” these batteries are trying to match and exercise used battery modules to create a good battery unit. This is hard to do.

The third option: try to rebuild it yourself. See all the arguments about why the after-market cost is lower. Rebuilding a battery is no small feat. At the end of it, you must be comfortable that all the battery modules have the same amp hours, the same voltage per SOC, the same charge/discharge rate, and relatively the same amount of dendrites (clumping of electrolyte) as their partners. This is done by charging and discharging battery modules one by one with DC chargers, monitoring the temp, voltage, and amperage it takes on the way up and the way down. Over and over, graphing it all, compiling it and deciding which modules must go and which can stay. It’s a lot of work and it might make for a fun hobby, but It takes a long, long time to do it even close to properly. There are machines that will do it for you, though they don’t seem to have much luck. If you plan on specializing in rebuilding batteries, then it’s up to you, let us know how it goes!

One last note about hybrid batteries. Most OEs insist they cool by air. Not very efficient, and it’s certainly less efficient when there is dog hair, blankets, or McDonald’s wrappers clogging the vents that the battery uses to breathe. Check out this clean vs dirty vent for the battery in this rear seat bolster courtesy of Toyota.

Rear Seat Vent

Here is a vent on an ‘04 Civic Hybrid, courtesy of Motor Authority.

Civic Hybrid Air Vent

Isolation Faults

This is an unfortunate but common failure among hybrid vehicles. Here’s a diagram of the hybrid drivetrain again.

Hybrid Wiring

Hybrids are designed so that all the “High Voltage” is in its own closed circuit, totally separate from the 12v circuit, totally separate from the vehicle chassis. The two cables leaving the high voltage battery are the battery positive and battery negative cables. They’re heavily insulated from chassis ground. The Inverter, the 3 phase cables going to the hybrid motor(s), and the motors themselves are all very heavily insulated from chassis ground. This is to protect the occupants of the vehicle, and the public in general, from electric shock. There is a minimum specification for this resistance to chassis: it must be at least 500 ohms per 1 volt of high voltage. For example, on a system that uses 300 volts, the spec would be 150,000 ohms minimum. Realistically, most OEs insulate much more than is needed, and the “Isolation Fault” codes tend to set long before it reaches this minimum limit.

When this insulation breaks down, it’s called an “Isolation Fault.” The Prius will try to help locate the fault with a “SubCode” along with a DTC.  The “SubCode” may be called an “INF” code, or “Information Code.” For example, P0AA6 is the generic fault, Hybrid Battery Voltage System Isolation Fault. But a P0AA6-613 is a fault that states “insulation resistance of HV transaxle or motor and generator inverters is low.” The hybrid vehicle ECU has determined that a breakdown of insulation exists in the Inverter, the cables from the Inverter to the transmission, or inside the transmission itself. Here is a lack-luster chart that Toyota uses to try to help.

Hybrid Inverter Diagram

The hybrid vehicle ECU is usually pretty good about narrowing down where the issue is, but be sure to use your insulation tester to verify. As a reminder, here’s what that piece of equipment looks like.

Hybrid Vehicle Insulation Tester

This model has several ranges of voltage it can use for testing. You must select between 50, 100, 250, 500, and 1000 volts. If there is no explicit range requested in the DTC troubleshooting, you want to pick the range that is not less than the system voltage you are working on. For example, the 05 Civic Hybrid has a system voltage of 144v, so you would pick 250v. The ‘03 Prius has a system voltage of 274v, so you would pick the 500v range on the meter. Be sure to read the DTC troubleshooting carefully for the desired range.

When you’re ready to test, for example, high voltage system disabled and high voltage connections exposed, put the Red insulation test lead on the component you are checking, and the Black lead to chassis ground. Take a deep breath and punch the big “Insulation Test” button on the meter. The meter will think about it for a second, and then spit out a number. Typically, you’re looking for the meter to max out on the high voltage battery, and the high voltage cables—this is about 550 M Ohms. Control devices like the Inverter are usually 2.9 M ohms. Motor/Generator stators have a resistance that will ramp up and the faster it ramps up to 550 M Ohms the better. If the resistance bounces up and down over and over, then that Motor/Generator stator is likely breaking down insulation to chassis.

If you find a reading that is low, then it’s time to start isolating the system. Remove the cables from the Inverter for example and test again on the mounts of the Inverter where the cables used to go. If the resistance is still low, then the Inverter has failed.


Now Start Diagnosing Some Hybrids

That covers many of the failures you’ll see on hybrids, and it might seem slightly confusing until you start putting a hand on the vehicle. Practice makes perfect, so collect your own set of “Known Typical” (I avoided Known-Good on purpose) data and resistance readings when time permits. The more comfortable you get with the tools and with the vehicles, the easier they’ll be to work with. Who knows, you might even decide to specialize! Like always, if you ever need a hand troubleshooting a vehicle, please give us a call on the hotline!


Fix of The Week 03/05/19

Fix of the week


Fix of The Week

Every week we’re posting our favorite head-scratchers and interesting mechanical issues submitted by our Direct-Hit customers.

For a chance to have something you’ve worked on appear as a Fix of the Week, and win a cool little prize for your shop, all you have to do is post your unique fixes in Direct-Hit. Just look up the vehicle you’re working on, click on Post Fix at the top right, then tell us the problem and what you did to fix it.

This Week’s Winners

On this edition of Fix of The Week: a clicking purge valve in a Hyundai, an inoperable hatch in a Lexus, and a shorted out horn in a Honda.


2016 Hyundai Tuscon – AutoCare Plus

When scanned, this vehicle showed code P0441—incorrect purge flow. The purge valve, when commanded on with scan tool, could be heard audibly clicking and during engine idle valve would sound like it was working as well. We put a vacuum gauge on the valve purge line side and watched the live data on the scan tool.

The purge valve first turned on at 5% duty cycle but the vacuum gauge wouldn’t show any flow, so we replaced the purge valve and reinstalled the vacuum gauge. When 5% duty cycle fist came on again, the vacuum gauge then showed flow. Even though the valve sounded like it was clicking, it wouldn’t produce any flow. Replacing the purge solenoid took care of the issue.


2010 Lexus RX350 – McDonald Auto Repair

This vehicle’s tailgate wouldn’t operate with the remote and had to be opened and closed manually. Close command from the up position would only result in the chime sounding with no initiation. We didn’t have access to software to check switches, so we took a guess and replaced the hatch struts since they were weak and not fully opening the hatch. The new struts allowed the tailgate to reach the full open position, allowing for proper operation. The hatch then worked normally with the remote.


1999 Honda CR-V – Ivy Truman Automotive

The customer complained that the shifter was stuck and the car couldn’t be shifted out of park. We also noticed the brake lights were not working. We found no power going into the brake light switch terminal 4 (WHT/GRN). Power is supplied to the brake light switch through 15amp STOP/HORN Fuse #52 (in the underhood fuse box) and it was blown. We put a 15amp fused current loop with an amp clamp in place to observe the amp draw on the circuit.

Everything worked as expected; the amp draw was low and looked completely acceptable while operating the brake switch and the shift interlock. However, when operating the horn, the amperage would shoot straight up and the 15a fuse would blow. We unplugged the horns (located behind the front grill and in front of the radiator) one at a time to find which one was shorting out. We replaced the rusted shorted out horn, fuse #52, and all was good.


Find these and 2 million other confirmed fixes in Direct-Hit. Get a 14 day test-drive for just $1.00

Electric Cars Go Back Further Than You Think

The Electric Car Is Older Than You Think

Throughout the next two months, we will be releasing a series of articles all about the electrification of the auto industry. We’re talking about electric vehicles, their history, how they work, how to service them, and what the trend towards more electric vehicles means for our industry. This is the first article in our series.

The Electric Car Is Not a new Idea

The battery-powered electric vehicle is older than you think. Here in the U.S., the first successful electric car made its debut around 1890 thanks to William Morrison, a chemist who lived in Des Moines, Iowa. His six-passenger vehicle, capable of a top speed of 14 miles per hour, was basically a wagon with an electric motor, but nonetheless helped jump-start an interest in building electric vehicles in the U.S.

By 1897, Pope manufacturing was producing electric taxis in NY. Battery electric vehicle development was going strong until Henry Ford added the Electric Automotive starter to the Model T in 1919. That made the gasoline-powered Model T easier and safer to start the hand crank models that came before it. Having an easy to start gasoline-powered car with filling stations to refuel created a market advantage that could not be rivaled by electric cars. So, by the 1920s the electric car became obsolete. Ironically, the electric motor helped kill the electric car of that era.

Development went dormant as gasoline was plentiful, environmental regulations were minimal, and the national highway system was built. Yes, as a country it was an accelerator pedal on the floor where displacement was king, horsepower ruled the roads, and cars became more luxurious through the years. It wasn’t until the environmental regulations and safety mandates of the ‘70s, coupled with higher gas prices and oil embargos, that the notion of the electric car would creep back into the minds of the industry yet again.

The Early Stages of Mainstream Electric Cars

Development on another electric car would begin again in the ‘90s with the GM EV1, and was driven partially by the 1990 CARB mandate for the 7 largest manufacturers to produce Zero Emission Vehicles (ZEVs) as part of their product line to continue selling vehicles in the state of California while helping combat air pollution.

Deliveries of the first leased EV1s began on December 5, 1996. The 137-horsepower Three Phase AC Motor, two-seat electric car had some interesting tech for its time: stop-by-wire brakes and electric steering. Weight reduction and low drag were also key parts of its development. The EV1 had an advertised 70-90-mile range for the production cars while using lead-acid batteries. Recharge times were 3.5 hours on a 220-volt charger and about 7.5 hours on a 110-volt charger. Real world driving range averaged closer to 40 to 50 miles per charge when driven in typical traffic and climatic situations.

The Gen 2 version with Nickel Metal Hydride (NiMH) battery upgrades that was released in the 99-model year was not enough to put off the inevitable end of the EV1. Production ended in 1999 when GM shut down the EV1 assembly line and CARB had assessed and removed the ZEV mandate as automakers would not be able to comply. The end of the electric car was here again, but not all was lost as many other EV1 projects were designed in tandem, like EV1 CNG, EV1 Series hybrid, EV1 Parallel hybrid, and the EV1 Fuel cell (Topics for another day). “GM admits it won’t recover the EV1’s $350-million development costs through the small volume of ‘sales’ (lease only), but the technology developed to reach these goals will be used in more mainstream products and will provide the basis for alternative-fuel vehicles in the future”. The inability of the OEMs to produce a marketable EV meant the next leap into electrification would be a hybrid vehicle (both internal combustion engine and electric motor-powered).

The Introduction of the Prius

The Toyota Prius was released in Japan in 1997 and was the first mass-produced hybrid electric vehicle of the time. The Prius used (NiMH) battery technology and it also used a gasoline engine to charge the high voltage battery and extend the range. Near the same time, Honda also came out with the Insight model, which used batteries to store energy for stop/start and as a power assist to the smaller gasoline engine. Prius sales were modest at the start, as consumers were wary of the vehicles, in part because they were very sluggish performers (it took the Prius 13 seconds to get from 0 to 60 mph, whereas the average car on the market could do it in 10 seconds).

This was the first time the world had seen or used an electric-gas-powered hybrid.  And even in the face of the bumpy start, Toyota must have done something right, because the Prius was still surpassing the number of sales estimated for the first year. In 2004, the second generation of the Prius was rolled out with better fuel mileage, a better drivetrain, and more space.

The Hybrid Synergy Drive system consisted of a 1.5L gasoline internal combustion engine (ICE) and a hybrid transmission. The transmission is essentially two electric motors (MG1 and MG2) on either side of a planetary gear set—Toyota calls this the “Power Split Device.” The gas engine produced 76 horsepower and 82 pound-feet of torque; next to the electric motor that produced the equivalent of 67 horsepower and 295 pound-feet of torque. (The net combined horsepower was increased to 110, giving the second generation a new time of 10 seconds when going from 0 to 60.) With the upgraded Hybrid Drive System, it was also able to get better fuel mileage as well. It now reached 48 mpg in the city and 45 mpg on the highway, giving it a grand combined total of 46 mpg. From 2004 to 2010, many production improvements were made to refine the car according to consumer demand.

Modern Hybrid Vehicles

In 2010, the Prius went through a complete redesign, and performance was the focus this time. It was outfitted with a new engine, improved steering, improved handling, better fuel efficiency, better drivetrain, and even a new platform. This is the Third Generation of the Prius and according to Toyota’s comments at the time, 90 percent of the hybrid system was new for this 2010 model. The engine was enlarged to 1.8 liters, has VVT and 98 horsepower compared to the 76 horsepower 1.5-liter engine. Combined output is up 24 horsepower to 134. RPMs are held much lower over the operating range with a significant reduction in noise vibration harshness (NVH). To reduce parasitic load on the engine, the drive belts are gone, and all accessories are now electric. Battery output was upped from 25 kilowatts to 27 kilowatts without changing the (NiMH) batteries. The increased power output comes from a redesign of the battery packaging, which saves weight and improves cooling performance.

When consumers posed the question, “Why can’t we plug these in and drive them as an EV?” Toyota responded and introduced a plug-in version in 2012. It was basically the same car, with a 4.4-kWh lithium-ion battery pack in place of the 1.3-kWh (NiMH) pack. There were also necessary upgrades to the cooling system to handle the greater energy demand and subsequent load. With a Toyota claimed range of up to 15 miles of pure electric range at speeds up to 62 mph, the plug-in could handle short trips on an all-electric operation. This model was developed, in part due to consumer demand, but also to compete with the recently released all-electric Nissan Leaf. Customers only needed to drop another $5,000 (fewer incentives) over the price of a standard Prius.

There are a lot of other hybrids on the market from many other manufacturers. Many of these help manufacturers meet CAFE standards so they can sell trucks and SUVs and have a smaller hybrid market share. For this article, we are focusing on the evolution of technology in general and the path it has taken to get to the current state. The Toyota Prius was the first and longest-running hybrid, which is why it has been chosen as the bridge to an EV (Electric Vehicle).

Prius Sales numbers since 2000: Sales of hybrid vehicles have a strong correlation to market forces like fuel prices. The graphs below show the distinct correlation between the two.

(Sales Data source:


Prius sales since 2000


(Average annual fuel prices are courtesy of the (EIA) Energy Information Administration)

Fuel Prices 2000-2018

Tesla and the Plug-In Electric Vehicle

Riding the market momentum of hybrids and rising gas prices, and CAFÉ standards from the Feds, enter the plug-in electric vehicle.

The Tesla Roadster, manufactured from 2008-2012, was a Tesla-engineered and built drivetrain in a Lotus Elise chassis. The Roadster was the first highway-legal serial production all-electric car to use lithium-ion battery cells and the first production all-electric car to travel more than 200 miles per charge. It sold 2,450 units in 30 countries. This was a fast and sophisticated vehicle that displayed all the modern technology of its time. With a base price of $98,500, this was hardly the EV for the common man. To be fair, Tesla has been the first manufacturer to go all EV in its entire lineup, but because of cost and availability, we are not focusing on it in this article.

The Nissan Leaf 2010 5-door hatchback using 24kWh lithium-ion battery pack represents the first affordable EV that can be bought and serviced from a major manufacturer. Considering that the MSRP for the 2011 Leaf was $32,780 and the base model Leaf in 2019 is $29,990, Nissan has held the mantle for the affordable EV. Claimed driving range and actual range are synonymous with the driving habits (much like gasoline vehicles). Drivers have found that the range available from a single charge can vary up to 40% in real-world situations—ranges from 62 miles to almost 138 miles have been reported. Driving style, load, traffic conditions, weather, and accessory use are the primary factors affecting driving range. Once again you will notice that the fluctuating gas prices have affected the sales of the Leaf annually. When gas prices are low consumers will buy gasoline/diesel vehicles for the ease of operation and convenience of daily use.


US Leaf sales 2010 –2018 Courtesy of (Car Sales


Nissan Leaf Annual Sales


(Average annual fuel prices are courtesy of the (EIA) Energy Information Administration)


Gas Prices 2010-2018


The Future of Electric Vehicles

So, what does all this mean? When will all cars be electric? How long will hybrids stay in the market? What about solar-powered vehicles? The questions can go on and on. Here are a few more to ponder.

How will we fund the development of infrastructure that can support charging EVs? When will the current limited range and the time required to charge batteries improve? What will give us better energy storage and performance than lithium-ion? What type of political mandates and regulations will come down the pike or which regulations and mandates will be removed?

These are all questions that continue to surround the EV debate. Other factors such as unpopularity in states with extreme cold or heat that heavily-tax electrical capacity through heating and cooling lead to further reduced range. Factors such as style, performance, and a strong connection many consumers still have with gasoline-powered vehicles will continue to influence a fledgling market place.

One thing we do know is that the electric car idea has been around for a long time and contrary to popular belief, “Big oil” didn’t buy patents and pay people off to keep gasoline in our daily lives. There never was a carburetor that produced 100 miles to the gallon. The market is the driving force and gives us the cars we currently drive and builds the car we would like to drive. Many things affect the market: Cost, demand, federal regulations, and affordability. Technology such as Ultracapacitors to store more energy to extend the range will continue to be explored and technological advancements will flow into the market if people will continue to buy electric cars. Consider this quote, attributed to both Abraham Lincoln and Peter Drucker: “The best way to predict the future is to create it.”


Statistical data is courtesy of Toyota Motor Corp. General Motors Corp. & Tesla and Historical data courtesy of