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

Symptoms

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

P0686 Description

The Engine Control Module (ECM) has detected a low voltage condition to the ECM.

P0686 Information for specific makes

P0686 AUDI
P0686 BMW
P0686 CHRYSLER
P0686 DODGE
P0686 ISUZU
P0686 JEEP
P0686 SUZUKI
P0686 VOLKSWAGEN