P0604 TOYOTA Internal Control Module Random Access Memory Error

Possible causes

– Faulty Engine Control Module (ECM)
– Engine Control Module (ECM) Harness power supply circuit is open or shorted
– Engine Control Module (ECM) Programming

Tech description

Check the ECM 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.

When is the obd code mean?

Indicates the ECM has experienced an internal memory fault.

Symptoms

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

P0604 TOYOTA OBD Code 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 ECM will set the code and illuminate the engine light.

TOYOTA Related P0604 code