P0603

DTC P0603
Circuit Description
A normal function of the Transmission Control Module (TCM) is to perform an internal test that verifies the integrity of the Non-Volatile Random Access Memory (NVRAM) allocation. This diagnostic detects faults in the allocation of NVRAM that contain the transmission adaptive pressure memory cells by comparing a calculated checksum with a stored checksum. When the TCM detects that the calculated checksum is different from the stored checksum, DTC P0603 sets. DTC P0603 is a type A DTC.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0603 Transmission Control Module (TCM) Long Term Memory Reset

Conditions for Running The DTC
The ignition is ON.

Conditions for Setting The DTC
The TCM NVRAM checksums do not match.

Action Taken When the DTC Sets
^ The TCM requests the ECM to illuminate the Malfunction Indicator Lamp (MIL).
^ The TCM turns off power to all solenoids.
^ The TCM commands maximum line pressure.
^ The TCM freezes transmission adaptive functions.
^ The High Side Driver 1 is commanded OFF.
^ The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame.
^ The TCM stores DTC P0603 in TCM history.

Conditions for Clearing the MIL/DTC
^ The ECM turns OFF the MIL after the sixth consecutive drive trip in which the TCM does not send a MIL illumination request.
^ A scan tool can clear the MIL/DTC.
^ The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring.
^ The TCM cancels the default actions when the ignition is OFF long enough in order to power down the TCM.

Diagnostic Aids
DTC P0603 may set as result of TCM reprogramming.

Test Description





The number below refers to the step number on the diagnostic table.
3. This step eliminates the TCM software as a possible cause of the DTC. If the DTC continues to set after reprogramming, the fault is in the TCM hardware.