P0604-INTERNAL CONTROL MODULE RAM

For a complete wiring diagram Refer to Section 8W

Theory of Operation

The Transmission Control Module (TCM) performs various internal tests to verify proper controller operation. If the TCM detects an error with the controllers Random Access Memory (RAM), the controller will enter Limp-in mode and illuminate the MIL.

• When Monitored:

  Continuously with the ignition on.

• Set Condition:

  If the TCM detects an error with the controllers Random Access Memory (RAM).

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)

Diagnostic Test

• Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM per the Service Information. Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/TRANSMISSION CONTROL MODULE for the appropriate service procedures.
• Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)