Symptoms

- Engine Light ON (or Service Engine Soon Warning Light) - No start

Possible Causes

- Generator circuit short to ground. - Generator circuit short to voltage. - Generator circuit open. - Battery-sense circuit open. - Generator drive mechanism. (belt) - Damaged generator/regulator assembly. - Damaged PCM.

Tech Notes

If the battery is OK then the alternator is more than likely the problem.

Description

The PCM monitors generator load from the generator/regulator in the form of frequency. The frequency range is determined by the temperature of the voltage regulator, where 97% indicates full load, and below 6% indicates no load.