DTC U0029(ACM System)
DTC U0029: F-CAN Malfunction (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). When the engine mount control unit does not receive the signals via the F-CAN lines for a set time, the engine mount control unit detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 3.5 seconds or more |
| DTC Type | One drive cycle, MIL 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 | 3 seconds | - |
| 12 volt battery voltage [BATTERY] | 10.0 V | - |
[ ]: HDS Parameter
Malfunction Threshold
The engine mount control unit does not receive any signals via the F-CAN lines for at least 3.5 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 B_H line open
- F-CAN circuit F-CAN B_L line open
- F-CAN circuit F-CAN B_H line short to ground
- F-CAN circuit F-CAN B_L line short to ground
- F-CAN circuit F-CAN B_H line short to F-CAN circuit F-CAN B_L line
- Engine mount control unit internal circuit failure
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM. The MIL does not come on.
Conditions for clearing the DTC
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.