DTC Advanced Diagnostics: U0129
DTC U0129:F-CAN Malfunction (Powertrain Control Module (PCM)-Electric Brake Booster)

General Description

The controller area network (CAN) transmits/receives pulsing signals to/from the control modules simultaneously by using F-CAN signal lines. If there is an abnormality in the electric brake booster 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
1.5 seconds or more
DTC Type
One drive cycle, MIL off

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
–
Vehicle
ON mode
[ ]: HDS Parameter

Malfunction Threshold
There is an abnormality in the electric brake booster system information transmitted from the electric brake booster for at least 1.5 seconds.
The information sent from the electric brake booster is abnormal at least 20 times.

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_H line open
F-CAN circuit F-CAN_L line open
F-CAN circuit F-CAN_H line short to ground
F-CAN circuit F-CAN_L line short to ground
Electric brake booster failure
PCM 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 memory. 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.