DTC U0129
DTC U0129: F-CAN Malfunction (Powertrain Control Module (PCM)-Electric Servo Brake Control Unit)
General Description
The controller area network (CAN) transmits/receives pulsing signals to/from the control modules simultaneously by using F-CAN B signal line. If there is an abnormality in the electric brake booster system information transmitted from the electric brake booster via the F-CAN line for a specified duration, the powertrain control module (PCM) detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 1 second or more |
| DTC Type | One drive cycle, MIL on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Elapsed time after the vehicle condition is turned to the ON mode | 3 seconds | - |
| 12 volt battery voltage [Battery] | 10.0 V | - |
[ ]: HDS Parameter
Malfunction Threshold
- There is an abnormality in the electric brake booster system information transmitted from the electric brake booster for at least 1 seconds.
- The information sent from the electric brake booster is abnormal at least 20 times.
Possible Cause
- Precision all wheel steer control unit failure
- 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
- Electric brake booster failure
- CAN gateway internal failure (include fuse fall-outs)
- PCM internal circuit 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 PCM 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 or by disconnecting the battery.