Aisin 81-40LE - Automatic Transmission (Non European Emissions)

DTC P0604 (Non European Emissions)

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0604 Transmission Control Module (TCM) Random Access Memory (RAM)

Conditions for Setting the DTC

* The transmission control module (TCM) cannot carry out the 4 random access memory (RAM) initialization routines.
* The TCM detects that the RAM cannot be written and read correctly.

Action Taken When the DTC Sets

The TCM will request the illumination of the hold lamp and store the DTC when the TCM detects failures on 2 consecutive ignition cycles.

Conditions for Clearing the DTC

* The TCM turns off the hold lamp when no further failures are detected on the next ignition cycles.
* The scan tool can clear the DTC from the TCM history.
* The TCM clears the DTC from the TCM history memory after 40 consecutive ignition cycles without fault.

Cause of Failure

* Harness or connector between TCM and engine control module (ECM)
* ECM
* TCM