How do you tell if car PCM is bad?
What Are the Symptoms of a Faulty PCM?
- Your “check engine” light is on.
- Other warning lights may be on, including traction control and ABS.
- You lose fuel economy for no apparent reason.
- Your car stutters when starting, requires multiple attempts, or won’t start at all.
- Stuttering or stalling during idling.
What is PCM failure?
PCMs 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.
Can you fix a bad PCM?
If everything in your car is good, but the check engine light is on, your PCM might be damaged. You can replace the damaged part or entire unit depending on the scale of damage. Bad PCM shouldn’t be a cause for worry, though, and many states allow drivers to pass checks despite the engine light is on.
How do I know if I need to replace my PCM?
7 Common PCM Failure Symptoms
- Your ‘Check Engine’ Light is On.
- Your Car Won’t Start or Starts Roughly.
- Sudden Loss of Gas Mileage.
- You Failed Your Emissions Test.
- Your Engine Stutters or Stalls.
- Erratic or Random Shifting.
- You’re Receiving a PCM-Related Error Code.
- What to Do If You Experience PCM Failure Symptoms.
What does a bad PCM look like?
Car May Not Run (will not crank, cranks but will not start) The PCM is also designed to control both ignition timing and spark. Problems with the PCM often result in the vehicle not running at all. In other cases, the vehicle may run poorly. Continuing to run a vehicle with a bad PCM could cause further damage.
How do you know if your PCM is fried?
Continuing to run a vehicle with a bad PCM could cause further damage. Because the PCM controls the emissions of your car, a failed emissions test or the presence of oddly-colored or foul smelling exhaust may be a sign that your PCM is going bad. A malfunctioning PCM will activate dashboard error lights.
How do I reset my Chevy PCM?
Remove the nut off the negative battery cable with a socket set or wrench. Slide the cable off of the battery and put it aside. Turn the headlight switch to the “on” position to drain the ecm of any remaining power. Wait at least 10 minutes, then turn it back to the “off” position.
