Transmission Diagnosis

DTC P0603 (3.0L)

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 memory cells by comparing a calculated check-sum with a stored check-sum. When the TCM detects that the calculated check-sum is different from the stored check-sum, DTC P0603 sets. DTC P0603 is a type A DTC.

Conditions for Running The DTC
The ignition is ON.

Conditions for Setting The DTC
The TCM NVRAM check-sums do not match.

Action Taken When the DTC Sets
^ The TCM requests the ECM to illuminate the Malfunction Indicator Lamp (MIL).
^ The TCM commands maximum line pressure.
^ The TCM freezes transmission adaptive functions.
^ The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
^ The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
^ The TCM stores DTC P0603 in TCM history.

Conditions for Clearing the MIL/DTC
^ The ECM turns OFF the MIL after the third 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 switch is OFF long enough in order to power down the TCM.

Steps 1 - 5:

DTC P0603 (3.0L)