Code 63

This DTC flashes the CHECK TRANS indicator and sets the BACKUP MODE.

CIRCUIT DESCRIPTION:
- The Erasable Programmable Read Only Memory (EPROM) is an electronic circuit that contains the commands that control the Transmission Control Module (TCM).
- The EPROM content is checked automatically approx. each second by the TCM. This is called Check Sum (CSUM) calculation. If this CSUM is false this means that one command is altered.
- This can be due to a circuit failure or a bad contact between the EPROM and the TCM and the DTC63 will be set.
- If all EPROM connections are bad, the TCM does not work. The CSUM can not be calculated and detected. Nothing works, not even the CHECK TRANS indicator.

DIAGNOSTIC AIDS:
- This Diagnostic is not an electrical test done by the TCM but a test between different information ("logic test").
- Detection conditions:
- Bad EPROM Check Sum
- The condition needs to be present for at least approx. 1 second.
- Action after the detection time: BACKUP MODE.
- Recovery conditions: To recover, do an IGNITION CYCLE.

To Solve the Problem
- Check the EPROM MEM-CAL connector.
If condition still exists, replace MEM-CAL.