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)

P0689 Information for specific makes

P0689 CHEVROLET
P0689 CHRYSLER
P0689 DODGE
P0689 FORD
P0689 ISUZU
P0689 JEEP
P0689 MAZDA
P0689 MITSUBISHI
P0689 SUZUKI