DTC Advanced Diagnostics: U0146(PGM-FI System (3.0L Engine))

DTC U0146: PF-CAN Malfunction (Powertrain Control Module (PCM)-CAN Gateway)

General Description

Courtesy of HONDA, U.S.A., INC.

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). If the powertrain control module (PCM) does not receive any signals from the CAN gateway via the F-CAN lines or if the information sent from the CAN gateway is abnormal, the 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 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 V	-

[ ]: HDS Parameter

Malfunction Threshold

One of these conditions is met:

The PCM does not receive any signals from the CAN gateway via the F-CAN lines for at least 1.5 seconds.
The information sent from the CAN gateway 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.

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 A_H line short to power
PF-CAN circuit PF-CAN A_L line short to power
PF-CAN circuit PF-CAN A_H line short to PF-CAN circuit PF-CAN A_L line
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
PF-CAN circuit PF-CAN B_H line short to power
PF-CAN circuit PF-CAN B_L line short to power
PF-CAN circuit PF-CAN B_H line short to PF-CAN circuit PF-CAN B_L line
CAN gateway 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, the freeze data, and the on-board snapshot are stored in the PCM memory.

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.