DTC U0029 (Battery Condition Monitor Module)
DTC U0029: F-CAN Malfunction (Battery Condition Monitor 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 F-CAN line is detected for a prescribed time, the battery control processor in the battery condition monitor 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 cycle, MIL on, POWER SYSTEM indicator on |
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 F-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.
- F-CAN circuit F-CAN A_H line open
- F-CAN circuit F-CAN A_L line open
- F-CAN circuit F-CAN A_H line short
- F-CAN circuit F-CAN A_L line short
- Unit communicating on F-CAN internal circuit failure
- Battery condition monitor module 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 battery condition monitor 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.