Engine torque information is sent to the transmission control module (TCM) by the engine control module (ECM) through the controller area network (CAN). A two-wire circuit is used to communicate data between the ECM and TCM, CAN H and CAN L. A fault in the CAN will not cause DTC P2637 to set by itself. If a communication fault occurs, other DTCs will set before P2637.
When the ECM sends the TCM an invalid engine torque, DTC P2637 sets. DTC P2637 is a type A DTC.
This diagnostic procedure supports the following DTC:
DTC P2637 Transmission Torque Delivered Circuit
No other CAN errors are present.
The engine torque is invalid for 1 second.
• | 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 P2637 in TCM history. |
• | 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 DTC default actions when the ignition switch is OFF long enough in order to power down the TCM. |
Step | Action | Yes | No | ||||
---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||
2 |
Important:
Did you record any ECM Failure Records? | Go to Step 3 | |||||
3 |
Did DTC P2637 set again? | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections | ||||
4 | Did any other DTCs set? | Go to Step 5 | |||||
5 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Is the action complete? | Go to Step 6 | -- | ||||
6 | Perform the following operation to verify the repair:
Has the test run and passed? | Go to Step 7 | Go to Step 2 | ||||
7 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | System OK |