DTC U1204 (Motor Control Module)
DTC U1204: EP-CAN Malfunction (Traction Motor Control Module - PCM)
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). When the motor control module in the power control unit (PCU) does not receive the signals from the powertrain control module (PCM) via the EPP-CAN lines or the received data is abnormal for a specified time, a malfunction is detected and a DTC is stored.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 2 seconds 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
One of these conditions is met for at least 2 seconds:
- The motor control module does not receive any signals via the EPP-CAN lines.
- The information sent from the PCM is abnormal.
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
- PCM 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.