DTC P2638
DTC P2638: Torque Management Feedback Signal A Range/Performance
General Description
The powertrain control module (PCM) executes the engine torque when requested from the transmission control module (TCM) and sends back the conditions to the TCM via the F-CAN line. The TCM then monitors whether the PCM executed the requested engine torque. If the difference between the TCM's requested engine torque and the PCM's executed engine torque is out of the specified range for a specified duration, the TCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 1 second or more |
| DTC Type | One drive cycle, MIL on*, A/T gear position indicator blinks |
*: MIL comes on at second drive cycle
Enable Conditions
| Condition | ||
|---|---|---|
| Vehicle | During shift change | |
Malfunction Threshold
One of these conditions is met:
- The absolute value difference between the decreasing sides of the TCM requested engine torque and the PCM executed engine torque is less than 0 % or more than 1, 000 % for at least 1 second.
- The absolute value difference between the increasing sides of the TCM requested engine torque and the PCM executed engine torque is less than 25 % or more than 1, 000 % for at least 1 second.
Possible Cause
The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- Refer to the specific DTC information
- TCM internal failure
Confirmation Procedure
Operating Condition
- 1.
Start the engine.
- 2.
Drive the vehicle, and let the transmission shift through several gears.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
With the HDS
None.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, the A/T gear position indicator blinks and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the TCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on.
Conditions for clearing the DTC
The A/T gear position indicator comes off by turning the vehicle to the OFF (LOCK) mode. The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command.