DTC U0029 (A/T)

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DTC U0029: F-CAN A Malfunction (Bus-Off)

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 (H line and L line). When the transmission control module (TCM) cannot send the signals via the F-CAN lines for a set time, the TCM 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, Shift position indicator blinks

Enable Conditions

Condition
Vehicle	ON mode

Malfunction Threshold

The TCM 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 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
TCM internal circuit failure

Confirmation Procedure

Operating Condition

Turn the vehicle to the ON mode, and wait for several seconds.

With the HDS

None.

Diagnosis Details

Conditions for setting the DTC

When a malfunction is detected, the MIL comes on, the shift position indicator blinks, and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the TCM memory.

Conditions for clearing the DTC

The shift position indicator comes off by turning the vehicle to the OFF (LOCK) mode. 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.