DTC Advanced Diagnostics: U0038 (302) (Generator Motor Control Module)
DTC U0038 (302): EP-CAN Malfunction (Generator 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 (EPP-CAN A_H and EPP-CAN A_L).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 CAN controller in the motor control module detects a malfunction and a DTC is stored.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 2.5 seconds or more |
| DTC Type | One drive cycles, MIL on, POWER SYSTEM indicator on, 12 volt battery charging system indicator off |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Elapsed time since the 12 volt battery voltage reaches to a specified value after the vehicle condition is turned to the ON mode | 50 milliseconds | - |
| 12 volt battery voltage | 10.2 V | - |
Malfunction Threshold
The EPP-CAN line bus-off continues for at least 2.5 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.
- EPP-CAN circuit EPP-CAN A_H line open
- EPP-CAN circuit EPP-CAN A_L line open
- EPP-CAN circuit EPP-CAN A_H line short to ground
- EPP-CAN circuit EPP-CAN A_L line short to ground
- Unit communicating on EPP-CAN internal circuit failure
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL and the POWER SYSTEM indicator 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 and the POWER SYSTEM indicator is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the POWER SYSTEM indicator, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.