P0604

P0604 - Internal Control Module RAM

For a complete wiring diagram, refer to.

Theory of Operation

After the controller is reset, the microprocessor checks the integrity of each RAM location by writing to it and reading back from it. The read value should be the same as the written value. The MIL will illuminate and the transmission will be placed into limp-in after 10 seconds of problem identification.

• When Monitored: One time after the ignition switch is turned to the RUN position.

• Set Condition: The read value does not match the written value in any RAM location.






Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure

Test Step 1 - PCM Internal Error

If there are no possible causes remaining, view repair.

Repair

• Using the schematics as a guide, check the PCM terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for service bulletins for any possible causes that may apply. If no problems are found, replace and program the PCM. With the scan tool, perform Quick Learn.

• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test