P0686 BMW Engine Control Module Power Relay Control Circuit Low

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 BMW OBD Code Description

ECM power relay control circuit low