Possible causes
– Weak battery- Low voltage while cranking
– Faulty Engine Control Module (ECM) relay
– Blown ECM fuse
– Faulty ECM
– ECM harness is open or shorted
– ECM circuit poor electrical connection
– Faulty Engine Control Module (ECM) relay
– Blown ECM fuse
– Faulty ECM
– ECM harness is open or shorted
– ECM circuit poor electrical connection
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P0686 DODGE OBD Code Description
The Engine Control Module (ECM) has detected a low voltage condition to the ECM.