DTC Advanced Diagnostics: U0029 (L15B7/L15BA/L15BY: Without CAN gateway (PGM-FI System))

DTC Advanced Diagnostics: U0029

DTC U0029:F-CAN Malfunction (BUS-OFF (Powertrain Control Module (PCM)))

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 send the signals 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 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]	10.0 V	–

[ ]: HDS Parameter

Malfunction Threshold

The PCM cannot send any signals via the F-CAN lines for at least 1 second.

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
	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, and the freeze data 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, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.