PCM module

Tiny
JENIFER FOWLER
  • MEMBER
  • 2016 CHEVROLET SPARK
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 3,000 MILES
My car would not start and the ignition kept turning over. Chevrolet dealership said it was
PCM module and replaced it. Got my car back on 7/26/16 and on 8/5/16 did the exact same thing. Do they know what they are doing?
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Thursday, August 18th, 2016 AT 10:18 PM

4 Replies

Tiny
CARADIODOC
  • EXPERT
The logical thing to do for starters is to assume the new part failed. The car should go to the same shop so the mechanic has the chance to inspect his work and correct any mistakes. Considering how extremely complex computer modules are, and the fact they live in the worst possible environment for electronics, it is amazing they don't fail more often. If this is indeed a second failure, your mechanic is going to investigate further for things that could have caused those failures. Normally the "driver circuits" have quite a bit of protection built in to avoid failures from things like shorted injectors or ignition coils. This is where you really need to know which part of the computer isn't working. The mechanic isn't in a position to know how the computer failed, but often the person repairing the computer can offer some suggestions.

It is also possible a mechanical problem within the computer caused the problem. A perfect example is those driver circuits I mentioned have high-power switching transistors, and for all transistors, heat is their deadly enemy. The power transistors are mounted to large metal "heat sinks" to draw the heat away from them. Sometimes the mechanical fastening device breaks or works loose, then the transistor can overheat and short. The rebuilder would see that and take care of it. There's no way the mechanic would know that happened.
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Thursday, August 18th, 2016 AT 11:47 PM
Tiny
JENIFER FOWLER
  • MEMBER
I appreciate your candid and honest answer, however, even though it is still under warranty, its kind of unnerving since I've only had the car since may 10 2016. And its been back to them for over 40 days.
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Friday, August 19th, 2016 AT 2:25 AM
Tiny
CARADIODOC
  • EXPERT
Every state is different, but here in Wisconsin, if a car is repaired three or more times under warranty for the same thing, you can open a lemon-law claim. That also applies to a car that is out-of-service for a certain percentage of days due to being stuck at the dealership, either waiting for parts or waiting for the problem to be figured out.

When Chrysler has a lemon-law buyback vehicle, they insist it must be properly repaired, regardless of cost, then it goes to a car auction. When GM has a buyback, they just give up and donate them to technical college Automotive programs. We had about a dozen of them at my school.

The problem with lemon-laws is the car owner never makes out. You think you're going to get back what you paid, but they deduct an amount equal to what it would have cost you to rent the car for as long as you had it. A week's worth of renting is a lot higher than a week's worth of leasing.

The good news, at least with Chrysler, is if the dealer is unable to help you, they will get the district representative involved, and he has way more authority over what can be done to solve the problem. The dealer is bound by franchise agreements and government regulations. The dealer is your advocate, not your adversary. The district rep. Is much more interested in keeping you happy than you would expect. Having your best interest at heart, it is preferable to figure out how to repair your car so this problem doesn't occur again. Even that can be frustrating because thanks to the four or five dozen computer modules, over half of them, and a whole long list of other things can cause no-start problems. It seems to be something today's drivers are willing to put up with. The frustrating part is all you know is the engine doesn't start, ... Again, but the cause can be totally different than the last time.

So far nothing you're described is unusual or out-of-the-ordinary. Since cars have become so unnecessarily complex, we see electrical problems all the time that defy diagnosis. My next concern is what are owners going to do when these cars get to be five to fifteen years old and the dealer no longer wants to work on them? I drive stuff that's 22 - 36 years old because if something needs to be repaired, I know I can do it myself. There's just too much on new cars that require a trip to the dealership. I'm a mechanic; I shouldn't have to go to someone else to fix what I'm trained to do.
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Friday, August 19th, 2016 AT 9:29 PM
Tiny
JENIFER FOWLER
  • MEMBER
Thank you so much. I appreciate it very much.
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Saturday, August 20th, 2016 AT 7:40 AM

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