DTC U0029: F-CAN Communication Line Error (BUS OFF)

NOTE:

SRS components are located in this area. Review the SRS component locations (see COMPONENT LOCATION INDEX ), and precautions and procedures (see PRECAUTIONS AND PROCEDURES ) before doing repairs or servicing.
Make sure the HDS communicates with the PCM and other vehicle systems. If it does not, go to DLC Circuit Troubleshooting (see DLC CIRCUIT TROUBLESHOOTING ).
If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Clear the DTCs with the HDS.
Turn the ignition switch to LOCK (0), and then back to ON (II), or press the engine start/stop button to select the OFF mode and then the ON mode.
Wait for at least 6 seconds.
Check for DTCs with the HDS.
Is DTC U0029 indicated?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time. Check for loose or poor connections, or worn/shorted wires. If the connections are good, check the battery condition (see BATTERY TEST ) and the charging system.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

Disconnect the appropriate connector at each control unit in the table one at a time. Clear the DTC, then recheck for DTCs after each unit is disconnected.

Control Unit

Connector

Gauge control module

Connector A (32P)

PCM

Connector A (49P)

VSA modulator-control unit

46P connector

SRS unit

Connector A (39P)

TPMS control unit

20P connector

Yaw rate-acceleration sensor

4P connector

Steering angle sensor

5P connector

SH-AWD control unit

Connector A (20P)

AcuraLink control unit⁽¹⁾

Connector A (32P)

E-pretensioner unit⁽²⁾

Connector B (14P)

Active damper control unit⁽³⁾

Connector A (14P)

ACC unit⁽²⁾

20P connector

⁽¹⁾	With AcuraLink

⁽²⁾

With ACC

⁽³⁾	With integrated dynamics system

Is DTC U0029 indicated after each individual unit was disconnected?

YES -Go to step 7.

NO -Replace the control unit that was disconnected when DTC U0029 did not set.

Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

Disconnect all the control units' connectors in the following table.

Control Unit

Connector

Gauge control module

Connector A (32P)

PCM

Connector A (49P)

VSA modulator-control unit

46P connector

SRS unit

Connector A (39P)

TPMS control unit

20P connector

Yaw rate-acceleration sensor

4P connector

Steering angle sensor

5P connector

SH-AWD control unit

Connector A (20P)

AcuraLink control unit⁽¹⁾

Connector A (32P)

E-pretensioner unit⁽²⁾

Connector B (14P)

Active damper control unit⁽³⁾

Connector A (14P)

ACC unit⁽²⁾

20P connector

⁽¹⁾	With AcuraLink

⁽²⁾

With ACC

⁽³⁾	With integrated dynamics system

Disconnect the HDS from the data link connector (DLC).
Check for continuity between body ground and gauge control module connector A (32P) terminals No. 13 and No. 14 individually.

Fig 1: Checking For Continuity Between Body Ground And Gauge Control Module Connector A (32P) Terminals No. 13 And No. 14
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short to ground in the F-CAN wire(s).

NO -Go to step 11.
Check for continuity between gauge control module connector A (32P) terminals No. 13 and No. 14.

Fig 2: Checking For Continuity Between Gauge Control Module Connector A (32P) Terminals No. 13 And No. 14
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short in the F-CAN wires.

NO -Replace the gauge control module (see GAUGE CONTROL MODULE REPLACEMENT ).