P0688 Mazda 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)
Mazda Vehicle:Mazda B-Series, Mazda CX-7,Mazda CX-9,Mazda MAZDA2,Mazda MAZDA3,Mazda MAZDA5,Mazda MAZDA6,Mazda Miata MX-5,Mazda RX-8,Mazda Tribute,Mazda RX-8,Mazda MX-5,Mazda CX-9,Mazda Atenza,Mazda Axela,Mazda Tribute,