VT25-E Automatic Transmission

VT25-E AUTOMATIC TRANSMISSION

DTC P0601
Circuit Description with VT25-E Automatic Transmission
A normal function of the transmission control module (TCM) is to perform an internal test that verifies the integrity of the ROM memory allocation. This diagnostic detects faults in the allocation of flash memory that contains the program and calibration by comparing a calculated checksum with a stored checksum. When the TCM detects that the calculated checksum is different from the stored checksum, DTC P0601 sets. DTC P0601 is a type A DTC.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0601 Transmission Control Module (TCM) Read Only Memory (ROM)

Conditions for Running The DTC
The engine is running.

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

Action Taken When the DTC Sets
^ The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
^ The TCM freezes all ratio control functions, including the ratio control motor and desired speed ratio.
^ The TCM discontinues use of the closed loop ratio control algorithm. This causes the speed ratio to be defaulted and possibly not accurate. The resulting open loop control may or may not provide optimum ratio performance.
^ The TCM inhibits TCC engagement.
^ The TCM commands maximum line pressure.
^ The TCM no longer inhibits shifting to between reverse and drive when moving.
^ The TCM turns power off to the TCC enable solenoid valve.
^ The TCM discontinues torque management.
^ The TCM freezes garage shift transmission adaptive functions.
^ The TCM freezes main line pressure transmission adaptive functions.
^ The TCM freezes torque converter clutch (TCC) 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 P0601 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.