Transmission Control Module

Transmission Control Module Description

The TCM performs six self-test integrity diagnostics on its internal hardware and software to check for faults, a fault is detected if:
1. The ignition supply is greater than 10.5V and the voltage across the relay coil is less than the ignition supply minus 2V.
The transmission controller's supply to the power output is faulty.
This could be due to a problem in the harness (short circuit to 12V of a power output stage), or an internal ECU fault.
2. The ignition supply is greater than 1O.5V and the voltage across the relay switch is less than the ignition supply minus 2V.
The transmission controllers supply to the power outputs is faulty.
This could be due to a problem in the harness (short circuit to OV), or internal ECU fault.
3. The ignition supply is greater than 1O.5V and the TCM cannot communicate with part of its internal memory.
This indicates a fault with Electrically Erasable Programmable Read Only Memory (EEPROM) communication.
4. The ignition supply is greater than 1O.5V and the calculated EEPROM checksum does not match the stored checksum.
This indicates an EEPROM checksum fault.
5. The engine speed is greater than 992 rpm and the permanent voltage supply to the TCM is less than 10V.
This indicates a permanent voltage supply fault.
6. The ignition supply is greater than 1O.5V and the internal TCM voltage is less than 4.5V or greater than 5.5V.

For the diagnostic table, please refer to the individual codes (i.e. P1562. P1601. P1606. P1612 or P1613).

If the above table does not include details of the following enabling conditions: - Intake Air Temperature (IAT), Engine Coolant Temperature (ECT), vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor.