DTC U0038 (CVT)
DTC U0038: TM-CAN Malfunction (TCM-PCM)
General Description
The transmission control module (TCM) and the powertrain control module (PCM) uses communication line (H line and L line) to transmit/receive multiple signals simultaneously. When the information is not sent from the PCM via the TM-CAN lines and this condition continues for a specified time, the TCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 1.5 seconds or more |
| DTC Type | One drive cycle, MIL on, Shift position indicator blinks |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| 12 volt battery voltage [Battery Voltage] | 10.0 V | - |
[ ]: HDS Parameter
Malfunction Threshold
The TCM does not receive any signals via the TM-CAN lines for at least 1.5 seconds.
Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- TM-CAN circuit TM-CAN_H line open
- TM-CAN circuit TM-CAN_L line open
- TM-CAN circuit TM-CAN_H line short to ground
- TM-CAN circuit TM-CAN_L line short to ground
- PCM failure (include fuse blown)
- TCM internal circuit failure
Confirmation Procedure
Operating Condition
Turn the vehicle to the ON mode, and wait for at least 1.5 seconds.
With the HDS
None.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on, the shift position indicator blinks, and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the TCM memory.
Conditions for clearing the DTC
The shift 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.