Q: Can you have a bad PCM but have no check engine light on?

asked by on October 27, 2016

My vehicle has all the necessary essentials to run ( spark, air, fuel. ) Witch makes me think it could be the pcm. But I do not have a check engine light on. Is it possible to have a bad PCM but not have a check engine light on?

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Hello and thank you for contacting YourMechanic. PCM’s typically fail for one of two reasons: voltage overloads (often due to a short in a solenoid or actuator circuit) or environmental factors (corrosion, thermal stress or vibration). If water gets inside a PCM, it can short circuits and set up irreversible corrosion that ruins electronic connections. The PCM should give you a code for P0600 through P0606 indicating that the computer has a processor error.

However, if the PCM is corrupt, then just like a desktop computer, there is no accessing anything and no codes are put out for the computer would have no way of sending a signal. If you need further assistance troubleshooting your PCM, then seek out a technician, such as one from YourMechanic, to come to your location for an inspection.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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