DTC U0038 (Motor Control Module)
DTC U0038: EP-CAN Malfunction (Traction Motor Control Module Bus-Off)
General Description
The controller area network (CAN) transmits/receives pulsing signals to/from the control modules simultaneously by using two signal lines (H line and L line). If the bus-off occurs due to an open or a short circuit in the EPP-CAN line is detected for a prescribed time, the motor control module in the power control unit (PCU) detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 500 milliseconds or more |
| DTC Type | One drive cycle, MIL on, POWER SYSTEM indicator on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Elapsed time after the vehicle condition is turned to the ON mode | 5 seconds | - |
| 12 volt battery voltage | 10 V | - |
Malfunction Threshold
The EPP-CAN line bus-off continues for at least 500 milliseconds.
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.
- EPP-CAN circuit EPP-CAN_H line open
- EPP-CAN circuit EPP-CAN_L line open
- EPP-CAN circuit EPP-CAN_H line short to ground
- EPP-CAN circuit EPP-CAN_L line short to ground
- Unit communicating on EPP-CAN internal circuit failure
- PCU internal failure
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the motor control module memory.
Conditions for clearing the DTC
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.