Powertrain Control Module (PCM) - 66RFE

P0604-INTERNAL CONTROL MODULE RAM

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

After the controller is reset (ignition turned to the RUN position), the microprocessor checks the integrity of each Random Access Memory (RAM) location by writing to it and reading back from it. The read value should be same as value written.

- When Monitored:
One time after the controller is reset (ignition turned to the RUN position).

- Set Condition:
When the Powertrain Control Module (PCM) detects an internal controller problem.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
CHECK WIRING AND CONNECTORS FOR INTERMITTENT OPERATION
1. 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.
2. Wiggle the wires while checking for shorted and open circuits.
3. Check Service Bulletins that may apply.

Were there any problems found?

Yes

- Repair the power and/or ground circuits to the PCM as necessary.
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. 66RFE Transmission Verification Test

No

- Replace the PCM. With the scan tool, perform Quick Learn.
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. 66RFE Transmission Verification Test