DTC U128D: Power Seat Control Unit Lost Communication With Gauge Control Module (VSP/NE Frame)

NOTE: 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).
Wait for at least 6 seconds.
Check for DTCs with the HDS.
Is DTC U128D indicated?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time. Check for loose or poor connections between the power seat control unit and the gauge control module.
From the BODY ELECTRICAL SYSTEM SELECT menu, select B-CAN CONTROL UNITS INFORMATION, and then select CHECK CONNECTED CONTROL UNITS.
Is the gauge control module detected?

YES -Go to step 10.

NO -Go to step 6.
Measure the voltage between body ground and gauge control module 32P connector terminals No. 1 and No. 17 individually.

Fig 1: Measuring Voltage Between Body Ground And Gauge Control Module 32P Connector Terminals No. 1 And No. 17
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 9.

NO -Go to step 7.
Turn the ignition switch to LOCK (0).
Check the No. B16 (10 A) fuse in the under-hood fuse/relay box and the No. C11 (7.5 A) fuse in the driver's under-dash fuse/relay box.
Are the fuses OK?

YES -Repair an open or high resistance in the No. B16 (10 A) and/or No. C11 (7.5 A) fuse circuit.

NO -Replace the fuse(s). If the fuse blows again, repair a short to ground in the No. B16 (10 A) and/or No. C11 (7.5 A) fuse circuit.
Measure the voltage between body ground and gauge control module 32P connector terminal No. 4.

Fig 2: Measuring Voltage Between Body Ground And Gauge Control Module 32P Connector Terminal No. 4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there less than 0.2 V?

YES -Go to step 10.

NO -Repair an open or high resistance in the ground wire or poor ground (G401).
Turn the ignition switch to LOCK (0).
Disconnect power seat control unit connector B (40P).
Disconnect the gauge control module 32P connector.
Check for continuity between power seat control unit connector B (40P) terminals No. 21 and No. 22 and gauge control module 32P connector terminals No. 29 and No. 30 respectively.

Fig 3: Checking Continuity Between Power Seat Control Unit Connector B (40P) Terminals No. 21 And No. 22
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Replace the gauge control module (see GAUGE CONTROL MODULE REPLACEMENT ).

NO -Repair an open or poor connection in the B-CAN wire(s) between the power seat control unit and the gauge control module.