P0688 Audi Electronic Control Module Power Relay Control Circuit Open
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
Tech description
Check all the ECM fuses, if the fuses are OK try replacing the ECM relay.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
Audi Vehicle:Audi A1,Audi A3,Audi A1,Audi A3,Audi A1,Audi A3,Audi A4,Audi A5,Audi Q3,Audi A5,Audi Q5,Audi A3,Audi A4,Audi A5,Audi TT,Audi Q3,Audi Q5,Audi S3,Audi TTS,Audi RS 3,Audi TT RS,Audi A7,Audi Q7,Audi A8,Audi A6,Audi S4,Audi S5,Audi Q5,Audi S6,Audi S8,Audi S5,Audi A8,Audi R8 V8,Audi RS 5,Audi S6,Audi R8 V10,Audi R8 GT,Audi A8L