Possible causes

– Loose or poor battery terminal connection
– Low battery charge
– ECM power supply circuit is open or shorted
– ECM Programing
– Faulty ECM

Tech notes

Check the ECM/PCM fuse, if fuse is OK try erasing the code first and if the code comes back you may have to reprogram or replaced the ECM/PCM.

When is the code detected?

Indicates the ECM has experienced an internal memory fault.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Engine may not start

P0604 Description

The ECM continuously monitors its own internal memory status, internal circuits, and output signals transmitted to the throttle actuator. This self-check insures that the ECM is functioning properly. If any malfunction is detected, the will ECM will set the code and illuminate the engine light.

P0604 Information for specific makes

P0604 BMW
P0604 FORD
P0604 ISUZU
P0604 KIA
P0604 LEXUS
P0604 MAZDA
P0604 MITSUBISHI
P0604 SUBARU
P0604 TOYOTA
P0604 VOLKSWAGEN
P0604 SCION
P0604 BUICK
P0604 CADILLAC
P0604 CHEVROLET
P0604 GMC
P0604 PONTIAC
P0604 SATURN