In the case of the A/C the problem is usually the ignition switch heating up and not providing power to the A/C clutch and the ABS computer. If you want to diagnose the problem, buy a wiring diagram for your vehicle form eautorepair.net or alldata.com (there are way to many GM models to list their wiring diagrams here) and test for power at the switched terminals when the problem happens. Or, just replace the ignition switch.

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you’ll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

© 2007 Rick Muscoplat

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Today, I hear DIYers whine every time their check engine light goes off and they have to get the codes scanned. My take on this is “GROW UP!!” If you want to do your own car repairs, you need a basic set of tools. And today, that means you have to own either a code reader or a scan tool. Don’t want to make the investment? Fine, then take it to a shop and pay them $100 a pop to hook up their scan tool.

Have I convinced you to buy your own scan tool yet? If so, let’s take a look at the offerings. Rather than review tools from every manufacturer, I’ll give you my bias right up front. SPX is a major tool manufacturer. They’ve been making specialty tools for most (GM and FORD all specify SPX’s tools) car makers for decades. When electronics came into play, Owatonna Tool Company (OTC) was the first to build scan tools for independent shops. OTC is owned by SPX. Next, SPX bought Actron, which used to be known as KalEquip (they made my tach/dwell meter back in the ‘60’s). They also bought AutoXRay. What I’m getting at is that SPX not only has direct connections to the car makers, but they own the top scan tool companies in the world. That’s why I tell readers to buy their tools.

What’s the difference between a code reader and a scan tool?

A code reader just reads the trouble code. That’s it. They’re cheap (less than $50), but they don’t do much for you. Once you get the code, you’re one step closer to solving the problem, but you’re still missing a LOT of critical information. If you’re a real cheapskate and only want to buy a code reader, here’s what to look for.

The cheapest code readers don’t have batteries. That means you can scan for the code and read the trouble code only as long as it’s plugged into the computer. Once you have the code, you’ll have to go to your home computer to look up the code definition. What a pain. But then again, you are a cheapskate. Oh, by the way, once you unplug it, the information is gone. So you’d better bring a pen and paper with you. But if you spend a bit more, the code reader will have a battery that maintains the code information in memory. Dig a little deeper and you’ll get a code reader with a back-lit screen. Dig deeper still and you’ll get a code reader that’ll spit out the code definitions right on the screen. And many of those higher end readers are update-able (as manufacturers develop new codes).

Or, get a real diagnostic tool

Let’s not kid each other—a code reader is a toy. Sure, it’ll give you the code, but that’s it. If you’re like most DIY’ers, you’ll get the code definition and replace every part mentioned in the trouble code. So if the code says oxygen sensor lean, you’ll replace the oxygen sensor. The parts manufacturer’s love people like you. Every year tens of thousands of perfectly good 02 sensors are replaced just because the trouble code contained the words oxygen sensor. Engine computers are smart, but they’re not that smart. They may tell you that the oxygen sensor is reporting a lean condition. You assume that means the sensor is bad. Most often it’s telling the truth, the exhaust stream really IS lean. What would cause that? Yup, a vacuum leak. But you won’t get to that point until you’re replaced an $80 sensor and wind up with another check engine light. How to get around that? Buy a scan tool that gives you live data and then learn how to interpret the data.

Here’s how live data helps you

When an engine computer sees a lean condition in the exhaust, the first thing it does is add more fuel to the mixture. This is called Fuel Trim. The computer tracks how much fuel it adds or subtracts. It can add or subtract up to 25%. So, if you’re seeing a lean or rich trouble code, the first thing you should do is look at the live fuel trim data. If the computer is adding fuel, that’s an indication of a vacuum leak. If it’s subtracting fuel, that’s an indication of a leaking fuel injector or a fuel pressure problem. Do you see where this is going? A scan tool gives you the data to actually diagnose the problem. THAT’s why you should pony up the money and buy a scan tool with live data. Yes, they’re expensive. But trust me, you’ll waste far more than that by replacing perfectly good parts because you were too cheap to buy a real diagnostic tool in the first place. Let’s see, you replaced both O2 sensors ($160) and the check engine light is still on. And the root problem was caused by a .25 vacuum hose? You could have owned a scan tool for close to that same money.

Buying Tips

I’m listing many models of Actron and AutoXray tools here. Do not buy them based on price. Read their specs and MAKE SURE the one you like actually works with your vehicle. Many of the less expensive scan tools do NOT read manufacturer-specific codes–especially on European vehicles. You’ll have to spend upwards of $300-$500 to get that capability. Finally, none of these inexpensive tools will read ABS, AIRBAG, Chassis, or Universal codes. To get that capability, you’ll have to spend about $2,000. Want that? Great. Buy an OTC Genisys scan tool.

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you’ll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

© 2007 Rick Muscoplat

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

The ONLY way to start the diagnostics to find out why the check engine light came on is to plug in a code reading tool and poll the computer. Once a trouble code sets and lights the light, that code is stored in computer memory. The code reader or scan tool (there’s a difference between the two) polls the computer memory and pulls up the trouble code. Some units decipher the code and tell you what it means in plain English, while others just pop up the code.

Once you have the code, you can do two things: 1) Fix the problem, or 2) Clear the code. Now, I get asked a lot “How to I clear the code or turn off the light.” I’ve got news for you, you’re not fooling anybody if you think you can turn off the light and then take your car or truck in for an emissions inspection. Because the computer will tell the inspector that you’ve just cleared the codes. The inspector will tell you to come back and have the car checked again after the computer has reset its readiness monitors. (See drive cycles to understand what you have to do after clearing codes to be able to take and emissions test).

And, you CANNOT reset ABS or SRS (airbag) lights. You have to fix the problem.

Finally, be aware that the computer tracks how many times you’ve started the car with the Check Engine light on. So, if you’re under warranty or driving a leased vehicle and think that you can dodge the charges for engine damage by claiming that the “light just came on,” think again. They can tell when the light first came on.

How to check codes

1) Take it to an auto parts store that checks codes for free. Most major retail auto parts stores (like Autozone, Advance Auto, O’Reilly) will scan your computer for free. But beware, their parts guys are NOT technicians. So if the trouble code translates into “Oxygen sensor lean,” I guarantee you the parts guy will sell you a new oxygen sensor. Do you need one? Well, what if the exhaust stream really IS lean and the oxygen sensor is telling the truth? $80 down the drain. Remember, parts stores are in business to sell parts. Don’t rely on them to diagnose problems.

2) Buy your own code reader or scan tool
In the early days of OBDII, code readers and scan tools cost a fortune and only professional technicians could afford them. But today you can buy a code reader for $40. All right, I can hear you whining. But before you go into a full pity-party, remember that “in the old days” we had to buy special tools to work on cars. Remember tach/dwell meters for setting “points” in the distributor? Or that timing light you had to use to set timing? How about those distributor wrenches that you only used once every 3 years? So get over it—you’re going to have to spend money on a new tool.

What’s the difference between a code reader and a scan tool?

A code reader reads codes—period. It doesn’t tap into the vehicle’s computer to display “live data.” Knowing the code if helpful, but it’s just a start towards diagnosing the root cause. The majority of Do It Yourselfers who buy code readers end up guessing at the problem and replace a LOT of parts unnecessarily. So you saved yourself a bunch of money on the code reader only to throw far more money into parts you didn’t need.

A scan tool, on the other hand, displays the same data that the computer receives from it’s sensors. If we follow the oxygen sensor example from above, the first thing I’d check in live data is the value for “Short-term Fuel Trim.” When the computer sees a lean condition, it figures it calculated the wrong air/fuel mixture. To correct the problem, it adds more fuel. That additional fuel is referred to as Fuel Trim and the value runs from 0 to 25%. So, in this case, if I were to see a fuel trim of 25% along with an oxygen sensor “lean” code, I would know that I had a huge vacuum leak. In other words, too much air is getting into the engine, the computer is trying to compensate for it and it has max’ed out it’s ability to correct it, and the oxygen sensor is still seeing a lean condition. Remember I told you a parts guy would sell you an oxygen sensor? Well, in this case, I’d be looking for a broken vacuum hose or a bad intake manifold gasket. There, you just save almost enough money on this single repair to justify owning a scan tool.

What else can you read on a scan tool?

Engine RPM, engine coolant temperature, radiator fan operation, transmission operation, barometric pressure, MAF, MAP, VSS, TPS sensor values –getting the picture? You can literally “look” into the computer and get the data.

So buy a scan tool and read up on how to use it and interpret the values.

I’ve listed some of the more popular models of code readers and scan tools below. But read the fine print on the model you want to buy. MAKE SURE IT WORKS ON YOUR VEHICLE. Also, these inexpensive scan tools only pull “P” codes. They will not read ABS, Airbag, or other manufacturer-specific codes. If you want to read all those codes, you’ll need to pony up about $4,000 for a professional model with all the software.

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you’ll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

© 2007 Rick Muscoplat

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Pinpointing cylinder misfire codes

People ask me about misfire codes after they’ve replaced all the spark plug wires, coil, and plugs and they still have the code. Here’s a quick explanation of how a pro would attack the problem.

First, if you’re getting a P0300 Random/Multiple Cylinder Misfire Detected code, that would indicate a universal problem that applies to all cylinders. In that case, start by checking fuel supply issues like poor fuel pressure caused by a bad pump, restricted fuel filter, or a defective fuel pressure regulator. If all those check out, look for a major vacuum leak or EGR valve leak. EGR is recalculating exhaust gas back into the intake manifold. If it isn’t operating properly and letting too much exhaust in, it will lean out the air fuel mixture to all cylinders. So check those things first. If you’re still seeing multiple misfire codes, it’s time to examine the timing chain or belt to see if the valve train is out of time with the crankshaft. That would cause poor valve sealing. Of course, in an abused engine, or one with a ton of miles, there’s always the possibility of poor cylinder compression or leaking valves. But that usually doesn’t cause misfires on all cylinders. So let’s take a look at individual cylinder misfire codes.

The thing to keep in mind about cylinder misfire codes is that the computer really doesn’t know whether the spark made it to the spark plug or not. All it knows is that a cylinder or isn’t contributing it’s fair share of power. How does the computer detect this? Easy. It looks at the crankshaft position sensor and calculates its rate of rotation. It knows when it fired the coil for a particular cylinder and it knows when it fired the fuel injector. So it looks to make sure that the crankshaft position sensor reflects that cylinder’s contribution to power. If the computer notices a SLOWDOWN in the RATE of the crankshaft rotation, it calculates backwards to see which cylinder isn’t doing it’s job.

Like I said earlier, the computer doesn’t know whether the spark actually occurred, so it’s mistake to always assume that a misfire means bad ignition. A misfire can certainly be caused by faulty ignition. But it can also be caused by poor fuel mixture—too much air or too little gas. Let’s look at the possibilities.

In a “too-lean” mixture situation, there’s too little gas present to make a good long fire. The computer could be commanding a lean mixture due to a dirty MAF sensor, a bad oxygen sensor, or a leaking fuel injector. In those cases, the computer is trying to throttle back the gas to correct for what it saw previously as a too rich mixture. Or, the lean mixture could be caused by the proper amount of gas AND a vacuum leak. So, the computer thinks it got the mixture right, but the vacuum leak screwed things up. Whatever the cause of the too-lean mixture, the result is always the same—there’s too little gas (in relation to the amount of air) and the flame goes out too soon due to lack of fuel. Yup, the computer calls that a misfire.

In a too-rich situation, the flame STILLS goes out to soon, only this time it’s flames out because there’s not oxygen to keep the fire going. Yup, that’s a misfire too.

So you have to think in broader terms than just ignition when it comes to misfires.

Ask yourself these questions:

Is the cylinder getting fuel (fuel pressure good)?
Is the injector clogged (too little gas)?
Is there a vacuum leak near that cylinder?
Is the EGR valve leaking?
Is the cylinder getting enough fuel flow (restricted fuel filter—may have pressure, but not enough volume)
Is an injector leaking (causing a rich misfire)
Is the compression good? (valves seating, timing right)

This is where a scan tool with live data can really help. By reading the “fuel trim” numbers, you can tell whether the computer is trying to compensate for a lean or rich condition. Unfortunately, the scan tools that provide that kind of information are pricey. Plan on spending at least $400 for a pro scan tool.

Hope that helps.

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you’ll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

© 2007 Rick Muscoplat

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Next, you should know that there’s really no such thing as a free wiring diagram or free shop manual. The cheap manuals (Haynes, Chilton, etc) have really lousy diagrams (in my opinion), which is why you see so many posts that say, “I have a Haynes manual but need a wiring diagram for….” The car companies are charging for all repair information these days and it’s not cheap. So in order to get your hands on good reliable information, you simply have to bite the bullet and pay for it. Here are your options.

1. eautorepair.net – This site is run by Mitchell on Demand, which is used by the pros. They redraw all the factory wiring diagrams so they are MUCH easier to read. Really, I’d rather use their diagrams than any factory manual. Their repair instructions are good too. The downside to this service is their lack of body repair information. You cannot get any door panel removal instructions or any interior door repair steps. The same goes for instrument panel removal. The upside is that their service is very accessible for DIY’ers. You can buy a 1-week subscription for $12. They also sell a 1-month and 1-year subscription.

2. Alldata – This site is like the eautorepair site except that they DO include some body repair information. They have diagrams that show how to remove door panels and some dash panels. Their wiring diagrams are all FACTORY diagrams. If you know how to read them, great. If not, it can be quite a challenge for the average DIYer. They offer a 1-year subscription for $27.

3. Factory shop manuals – There’s no comparison here. These are the best manuals out there. They have the most diagrams and the best instructions. They also include in-depth articles on how the systems work. That can really help you when it comes to diagnosing a problem. The downside? The cost. Click here to find the site for your make. http://www.oem1stop.com/

3. Public library – That’s right, you forgot about them, didn’t you. Many public libraries subscribe to online repair services. If you have a library card you can use their computers and print out the repair instructions or diagrams for a small fee. The downside is that most libraries require you to access the service from inside the library—meaning, you can’t get it from home.

4. Ebay – If you sign on to ebaymotors, you’ll find tons of factory DVDs for cheap prices. Often these are bootleg copies. But if you’re concerned about whether they’re selling a legit copy, ask the seller.

Here’s the bottom line, and there is NO way around it—if you want reliable information, you’re going to have to pay for it. You would not believe the number of emails I get from people who have wasted days trying to fix their cars with the wrong wiring diagram, torque specs, or incorrect or missing repair steps. If only they had spend a few bucks on a subscription, they could have read the latest technical service bulletin warning them NOT to replace the entire ABS control module simply because the ground wire needed cleaning. Yes, it happens that often.

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you’ll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

© 2007 Rick Muscoplat

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

THE WRONG WAY

Disconnecting the battery cables while the vehicle is running can generate a voltage spike as high as 150 volts! That’s enough to fry every computer in your vehicle, along with your stereo, fuses, remote door locks, etc. Reconnecting battery cables generates a second spike.

THE RIGHT WAY

The battery must be fully charged and a volt meter must read at least 12.6 volts with the engine off and no loads (headlights off, etc). Next, start the vehicle and apply the voltmeter. It should read between 13 and 15 volts. Be aware that newer vehicles DO NOT CHARGE the battery unless it needs charging!!

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you’ll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

© 2007 Rick Muscoplat

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Here’s an example of a drive cycle readiness routine for a Chevrolet Trailblazer.

At least 17 hours have elapsed since the last drive cycle met and passed the test criteria. That means you can’t clear codes and immediately try to perform a drive cycle and zoom off to the testing station. Remember, minimum of 17 hours.

Check engine light is off.

No Emission related trouble codes are present.

BARO signal more than 74 kPa.

Battery voltage between 10-18v.

Difference between the ECT and IAT signals less than 14ºF at startup. In other words, the two sensors must be good.

Engine coolant temp between 39-86ºF at startup. Can’t start this test on a sub-zero day.

Intake air temp signal between 39-86ºF at startup.

Fuel level between 25-75%.

If you meet all those criteria, then

1. Start the engine and allow it run at idle speed for 15 seconds.
2. Accelerate at part-throttle to 45 mph and maintain that speed until the engine reaches normal operating temperature (this can take up to 10 minutes).
3. Drive for another 3 minutes at 45 mph on a flat road without climbing any hills to minimize the fuel slosh. Bring the vehicle to a stop in a safe place, but do not turn off the
ignition key.
4. On the scan tool or code reader with readiness monitor feature, check the status of the readiness code for the EVAP System Monitor. The Readiness code should change to
YES when the test is done. If it does, return home turn off the ignition key.

If it does not, check for any temporary codes. If no temporary codes are set, return to step 3 and repeat the test procedure. Check the status of the Readiness code for the EVAP System Monitor. The Readiness code should change to YES when the test is done.

NOTE:
Extremely high or low ambient temperatures may prevent this test from running. If the test is interrupted before completion, do all of the test steps from the beginning. If a small leak is detected during testing, a minimum of 3 drive cycles may be required before the EVAP Monitor status will update to YES. Performing a visual inspection prior to running the EVAP test may prevent having to repeat the test. An aborted or failed test will require the vehicle to cool down in order to meet the test conditions to run another test sequence.

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you’ll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

© 2007 Rick Muscoplat

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I’ve written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you’ve had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Here’s how to do it: Turn the key to ON but don’t start the engine. Press and release the accelerator pedal slowly three times. You must complete this within three seconds. Then turn the key to the OFF position. If the Change Engine Oil light comes back on, repeat the procedure until it goes out and stays out.

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you’ll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

© 2007 Rick Muscoplat

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I’ve written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you’ve had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

An aftermarket warranty is similar to an insurance policy. In some states, these warranties are regulated by the state’s insurance commissioner. That means they must be registered and be underwritten. If you’re buying an aftermarket warranty, you WANT one that’s underwritten. That means the warranty company has purchased and INSURANCE policy to cover your claims in the event the warranty company itself goes out of business. If you buy an extended warranty from a company that isn’t underwritten and they go out of business, you’re basically SCREWED. It happens all the time. Warranty companies open up, collect your money, pay a few claims (refuse payment on most claims) and then, when the word starts getting around that they don’t pay their claims, they fold up and disappear.

Which is better?

Almost universally, the factory extended warranty offers better coverage. But don’t assume that just because you buy a warranty from a dealer, that you’re getting a factory warranty. Car dealers can sell any warranty they want. Why would they sell you an aftermarket warranty? Simple. They make more money on them.

Since the factory warranties cover more, they also cost more. But dealers don’t like selling them because the profit margins are lower. Depending on the make, car dealers can make almost 40% profit on a factory warranty. When you consider that they sell for almost $2,000, that adds quite a bit of profit to the sale of a new car. But an aftermarket warranty can net them almost 60% profit. Which would you sell?

Understand your obligations

No warranty is going to cover your vehicle if you haven’t done your part. That means you must perform all the recommended maintenance and BE ABLE TO PROVE IT. Yes, you have to save ALL your receipts. And, you have to do each recommended service at the proper mileage or time specified in the owner’s manuals. Skip the maintenance and you risk having your entire claim denied.

How to read the fine print.

Since the warranty is like an insurance policy, you can’t just gloss over the page and assume you’re covered. The first section to read is the EXCLUSIONS: Extended warranties do not cover maintenance (oil, fluid, coolant changes, AC recharge, spark plug changes, bulbs, belts, tires, brakes, etc). They also routinely exclude squeaks and rattles (that means annoying non-specific squeaks and rattles). But if the squeak or rattle is caused by the failure of a covered component, it should be covered. Example, you’ve changed your oil religiously and the oil pump is starting to fail. You take it in for service because you hear a knocking sound. A weasel company will automatically deny the claim due to the “squeak clause.” But a real company will belly up and pay for the oil pump. See how this works? Look specifically for this deal breaker: emissions or emissions components. If you see that phrase, it means you’re not covered for any computers, sensors, or malfunctions of the fuel, ignition, or catalytic converter systems in the vehicle. And that’s where you’re liable to ring up the most repairs! If the warranty excludes those, walk away.

The next section to read is the DEFINITIONS: This one is really important. The word failure means different things to the consumer than it does to the warranty company. Since you’re bound by THEIR definition, you’d better read it upfront. Do NOT depend on the salesperson or the finance person to give you their interpretation of what the terms mean. They’ll be long gone when it’s time for you to file a claim.

Here’s what to look for:

Failure – a component can fail to perform its intended function for several reasons. It could be defective. It could be worn out from normal wear and tear. Or, it could be damaged by another component that failed. You guessed it, you want the definition to include all three. Weasel companies will define a failure as a defect only. Part wore out? So sorry. Not covered.

Fluids – I said above that no warranty will cover normal maintenance. But what if your air conditioning compressor springs a leak and all the refrigerant leaks out? They should cover the cost of the new compressor AND the new refrigerant because the refrigerant loss was due to the failure of a covered part. Get it?

Diagnostic charges – You don’t want your mechanic guessing what’s wrong with your car. Neither does your warranty company. They want it fixed right the first time. They just don’t want to pay for a proper diagnosis. A weasel company will work it this way: “We will pay for the cost of tear-down and inspection IF the failure is a covered component.” I have seen companies deny coverage for performing a computer scan. In those instances, you have wait until they discover the root cause and then fight with them over the definition of “teardown and inspection.” Is a scan a teardown? I’ve won the argument by claiming that a scan is an inspection and that a teardown to find the root cause would actually have been more expensive. But the bottom line is this: Do you even want to have this fight in the first place? Don’t buy from a weasel company.

Can they tell you where to have it fixed?

Most warranty companies go out of their way to tell you that you can take your car to any repair shop. But they also know that the dealer will be more expensive than an independent shop. So how do the weasel companies get around this? They have a clause in the policy that says they will pay the “reasonable and customary” charges. Then, when you submit the claim, they’ll tell you that the dealer’s labor charges are higher than reasonable and customary. You can counter that by conducting a survey of all dealers in your area to prove that your dealer’s charges are in-line with all the other dealers. But do you really want to spend your time that way? The warranty company cannot force you to take your vehicle to a less expensive shop unless they include that provision in their policy.

New parts? Old parts?

Here’s when things can get really hairy. Many times the dealer doesn’t sell rebuilt parts. A new alternator for a BMW from the dealer is almost $900. A rebuilt alternator for the same vehicle is $400. A used one is $150. Guess which one the warranty company wants? You can insist on a new one, but only if your warranty says that. Find out exactly what the warranty says about parts before you buy it!!

How to negotiate the price of a factory warranty.

I said earlier that factory warranties are NEGOTIABLE. No dealer will openly admit that. They insist that they cannot deal on a factory warranty.

Here’s how to haggle for a discounted price. Meet with the finance people and agree to every single item they try to sell you. Warranty, glass protection, paint sealant, etc. Then ask what the new payment will be. In the meantime, the finance person will be figuring out how they intend to spend their commission (yeah, they work on commission). When you hear the new monthly payment, freak out and tell them to take it all off–including the warranty. Then tell them you’ll buy your warranty online. They’ll tell you that those are no good. You tell them you know someone who has a really good online warranty company. Be prepared to walk out on the deal (not really). At the very end, they’ll drop the price. I’ve done this with my car, my son’s car, and my daughter’s. Works every time. After they’ve mentally spent their commission, they won’t want to let you walk out without buying it from them—even at a discounted price. Hey, car buying is a blood sport.

How to find a good aftermarket warranty

Talk to one of the service writers at a dealership. They work with the aftermarket warranty companies all day. The weasel companies take up their time and put them in the middle between the mechanic who wants to fix the problem and the warranty company that doesn’t want to pay for it. They know which companies are the goods ones, and they keep a black list of the companies that won’t pay or make life miserable. Ask them. They’ll tell you.

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you’ll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

© 2007 Rick Muscoplat

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Using the wrong “Rocking” technique can destroy your transmission.

If you’ve been taught to rock yourself out of a rut, snow, or ice by shifting from R to D, PAY ATTENTION TO THIS ARTICLE.

If you use that technique, I can just about guarantee you that you’ll destroy your transmission. Yeah, I know, you’ve done it before with no damage. Well, you were lucky. The transmissions in late model vehicles simply cannot take that kind of abuse.

Here’s how the damage happens. You put the vehicle in D and give it gas. The transmission immediately goes through the 1-2 and 2-3 shift. That means clutch packs pressurize, and bands apply. Before all the spinning parts have a chance to stop, you slam it into R. All those clutches disengage, bands move, and it shifts into reverse. The clutch material starts to overheat from being applied so quickly. Also, the high pressure needed to engage and disengage those clutches heats up the transmission fluid. Then you move it back into D and the procedure repeats. Over and over again.

By the time you’re out of the ditch, you’ve glazed the clutch disks and possibly warped the steel spacer rings. That damage is permanent and it will come back to haunt you. Maybe not right away. But within six months, your transmission will scream for mercy. And when it goes, you won’t connect its demise with that “stuck in the snow” incident from last winter.

What’s the PROPER way to rock a vehicle?

Move the shift level to LOW gear. Slowly apply the gas. The wheels will start to spin and begin to move the vehicle up the rut. Do NOT exceed 15MPH on the speedo. When you reach the maximum forward movement, take your foot OFF the gas. Let inertia roll you back into the ditch. Then give it gas again. Use the vehicle’s weight and inertia to get you out.

This procedure keeps the transmission in low gear. That locks out the 1-2 and 3-4 shift and eliminates Reverse from the equation.

If you can’t get unstuck, CALL A FREAKING TOW TRUCK. It’s a LOT cheaper than a new transmission.