DTC Advanced Diagnostics: U129E
DTC U129E:F-CAN Malfunction (Powertrain Control Module (PCM)-Power Control Unit (PCU))

General Description

The controller area network (CAN) transmits/receives pulsing signals to/from the control modules simultaneously by using two signal lines (F-CAN_H and F-CAN_L). When the information is not sent from the body control module via the F-CAN lines and this condition continues for a specified time or when the information sent from the body control module is abnormal and this condition continues for a specified cycle, 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
–
[ ]: HDS Parameter

Malfunction Threshold
Either of the condition is met:
The PCM cannot receive any signals from the body control module via the F-CAN A lines for at least 1.5 seconds.
The information sent from the body control module 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 A_H line open
F-CAN circuit F-CAN A_L line open
F-CAN circuit F-CAN A_H line short to ground
F-CAN circuit F-CAN A_L line short to ground
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
Body control module failure (include fuse fall-outs)
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.