what symptoms of gm pcm could positively cause it to be unfixable?

2 Answers

  • Evil C
    Lv 7
    3 months ago

    PCMs are basically just printed circuit boards in a metal casing much like what you find on the motherboard of your desktop PC. To that end they can be subjected to hardware failures that cannot be seen with the naked eye, but rather detected through the use of a scan tool which itself is a computer designed to talk to PCMs. The most common symptom of a bad PCM is an inability to establish communication with the scan tool when the data port wiring and connections are known to be in good functional condition. However PCMs can also suffer from partial failures as well which can be a little more tricky to detect, such as drivers in the software that become corrupted or dead which causes a corresponding engine control system to not function or function improperly. In any case, usually the best option would be is to replace and reprogram the PCM because to physically analyze the circuitry of the PCM itself would get time consuming and even expensive, and therefore not cost effective for an auto shop to perform. The only other thing that would render a PCM completely unfixable is if it were physically damaged to the point of functional compromise. This would most likely be the case if the vehicle were involved in an accident though, and if that happened, chances are the vehicle would be totaled out before a new PCM could even be considered.

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  • Anonymous
    4 months ago

    A symptom does not cause the PCM to be unfixable.  A bad PCM will show symptoms.  A car that cranks but will not start could be a sign that the PCM is bad.  But the PCM is the LAST PART to be checked when the car has symptoms that maybe due to a bad PCM.

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