DTC Advanced Diagnostics: U0146 (2.0L Engine, PGM-FI System) (2024 2025)
DTC U0146 : PF-CAN Malfunction (Powertrain Control Module (PCM)-CAN Gateway)
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) does not receive the signals from the CAN gateway via the CAN lines for a certain period of time or receives incorrect message frames, 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 on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Elapsed time since the 12 volt battery voltage reaches a specified value | 5.0 seconds | - |
| 12 volt battery voltage [Battery] | 10.04 V | - |
| Vehicle | ON mode | |
[ ]: HDS Parameter
Malfunction Threshold
Any of the conditions is met for at least 1 second:
- Checksum error
The value of checksum for the received frame is different from the calculated checksum.
- Message counter error
-
- -
The two consecutive values of the message counter are equal at least once.
- -
The difference between two consecutive values of the message counter is greater than 255.
- -
- Timeout error
The CAN message frame is not received.
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 B_H line open
- PF-CAN circuit PF-CAN B_L line open
- PF-CAN circuit PF-CAN B_H line short to ground
- PF-CAN circuit PF-CAN B_L line short to ground
- CAN gateway failure (include fuse blown)
- 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, the freeze data, and the on-board snapshot 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, the freeze data, and the on-board snapshot can be cleared with the scan tool clear command.