DTC Advanced Diagnostics: U0128 (PGM-FI System (3.5L Engine)) (2025)
DTC U0128 : PF-CAN Malfunction (Powertrain Control Module (PCM)-Electric Parking Brake Control Unit)
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 powertrain control module (PCM) cannot receive the signals from the VSA modulator-control unit via the F-CAN lines for a set time, the 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 off |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| 12 volt battery voltage [Battery] | 10.0 V | - |
| Vehicle | ON mode | |
[ ]: HDS Parameter
Malfunction Threshold
The PCM cannot receive any signals from the VSA modulator-control unit via the F-CAN lines for at least 1 second.
Possible Cause
The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- PF-CAN circuit PF-CAN A_H line open
- PF-CAN circuit PF-CAN A_L line open
- PF-CAN circuit PF-CAN A_H line short to ground
- PF-CAN circuit PF-CAN A_L line short to ground
- PF-CAN circuit PF-CAN C_H line open
- PF-CAN circuit PF-CAN C_L line open
- PF-CAN circuit PF-CAN C_H line short to ground
- PF-CAN circuit PF-CAN C_L line short to ground
- VF-CAN circuit VF-CAN A_H line open
- VF-CAN circuit VF-CAN A_L line open
- VF-CAN circuit VF-CAN A_H line short to ground
- VF-CAN circuit VF-CAN A_L line short to ground
- VSA modulator-control unit 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, the freeze data, and the on-board snapshot are stored in the PCM memory. The MIL does not come on.
Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, the freeze data, and the on-board snapshot can be cleared with the scan tool clear command.