Symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

Possible Causes

- ECM/PCM Programming error - Faulty or wrong ECM/PCM

When Detected

Mileage on odometer does not agree with mileage in Engine Control Module (ECM) or Powertrain Control Module (PCM)

Tech Notes

If a new ECM/PCM is installed in a vehicle, the mileage has to be reprogrammed to the new ECM/PCM

Description

On some vehicle the mileage on odometer is stored in the Engine Control Module (ECM) or Powertrain Control Module (PCM).