P0605

P0605-INTERNAL CONTROL MODULE ROM



Theory of Operation

After the controller is reset (ignition on from an off position), the microprocessor checks the integrity of the program memory (ROM). A checksum is calculated by adding all used bytes in the program memory. The sum should be the same as a known constant stored in memory. If the integrity of the program memory fails, the MIL will illuminate after 10 seconds of vehicle operation and transmission will be placed in limp-in.

- When Monitored:
One time after each time the ignition is turned to the run position from an off position.

- Set Condition:
If the integrity of the program memory (ROM) checksum does not match a known constant.





Always perform the 40/41TE Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure
PCM - INTERNAL ERROR

Repair

- Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for any Service Bulletins that may apply. If no problems are found, replace and program the PCM. With the scan tool perform the Quick Learn procedure Quick Learn Procedure.
- Perform 40/41TE TRANSMISSION VERIFICATION TEST 40/41TE Transmission Verification Test