P2637
DTC P2637
Circuit Description
Engine torque information is sent to the transmission control module (TCM) by the engine control module (ECM) through a communication network called the controller area network (CAN). Two circuits are used to communicate CAN data between the ECM and TCM. A fault in the CAN will not cause DTC P2637 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P2637.
When the ECM sends the TCM an engine torque signal that is invalid, DTC P2637 will set. DTC P2637 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P2637 Transmission Torque Delivered Circuit
Conditions for Running the DTC
^ The engine run time is greater than 5 seconds.
^ No other CAN errors are present.
Conditions for Setting the DTC
Engine torque signal is below the lower limit, above the upper limit, or is an unreliable value for 2 seconds.
Action Taken When the DTC Sets
^ The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
^ The TCM turns off the pressure control solenoid. When the pressure control solenoid is off, line pressure is at maximum.
^ The TCM freezes transmission adaptive functions.
^ The TCM inhibits Autograde braking and shift stabilization.
^ At the time of the first failure, the TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record.
^ At the time of the second failure, 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 P2637 in TCM history.
Conditions for Clearing the 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 DTC.
^ The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non emission related diagnostic fault occurring.
^ The TCM cancels the DTC default actions when the ignition is OFF long enough in order to power down the TCM.
