DTC U128D: Power Control Unit Lost Communication With Gauge Control Module

DTC (Power Control Unit)

NOTE:  If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to: BODY ELECTRICAL TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A - INITIAL COMMUNICATION AND DTC CHECKS .

1. Problem verification

   - 1. Clear the DTCs with the HDS.

   - 2. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

   - 3. Wait for at least 6 seconds.

   - 4. Check for DTCs with the HDS.

   DTC Description	DTC
   U128D Power Control Unit Lost Communication with Gauge Control Module

   Is DTC U128D indicated?

   YES 

   Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Check for loose or poor connections.

2. Determine possible failure area (gauge control module power and ground, B-CAN line)

   - 1. Select B-CAN CONTROL UNITS INFORMATION from the BODY ELECTRICAL SYSTEM SELECT menu, and then select CHECK CONNECTED CONTROL UNITS.

   - 2. Check the DETECT/NOT AVAILABLE information of the GAUGE CONTROL MODULE.

   Is DETECT indicated?

   YES 

   Go to step 8.

   NO 

   Go to step 3.

3. Fuse check

   - 1. Check the following fuses.

   Fuse	No. A21 (10 A)
   Location	Under-hood fuse/relay box

   Fuse	No. B5 (10 A)
   Location	Under-dash fuse/relay box

   Is each fuse OK?

   YES 

   Go to step 4.

   NO 

   Replace the fuse. If the fuse blows again, repair a short to ground in the No. A21 (10 A) and/or the No. B5 (10 A) fuse circuit(s).

4. Open wire check (+B BACK UP line)

   - 1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Disconnect the following connector.

   GAUGE CONTROL MODULE CONNECTOR A (32P)

   - 3. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Gauge control module connector A (32P): disconnected
   Test circuit	+B BACK UP
   Test point 1	Gauge control module connector A (32P) No. 1 (WHT)
   Test point 2	Body ground

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

   Is there battery voltage?

   YES 

   The +B BACK UP wire is OK. Go to step 5.

   NO 

   Repair an open or high resistance in the wire.

5. Open wire check (IG1 METER line)

   - 1. Turn the vehicle to the ON mode.

   - 2. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode Gauge control module connector A (32P): disconnected
   Test circuit	IG1 METER
   Test point 1	Gauge control module connector A (32P) No. 17 (BRN)
   Test point 2	Body ground

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

   Is there battery voltage?

   YES 

   The IG1 METER wire is OK. Go to step 6.

   NO 

   Repair an open or high resistance in the wire.

6. Open wire check (GND lines)

   - 1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Check for continuity between test points 1 and 2 individually.

   Test condition	Vehicle OFF (LOCK) mode Gauge control module connector A (32P): disconnected
   Test circuit	GND
   Test point 1	Gauge control module connector A (32P) No. 4 (BRN)
   Test point 2	Body ground

   Test circuit	GND
   Test point 1	Gauge control module connector A (32P) No. 32 (BRN)
   Test point 2	Body ground

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

   Is there continuity?

   YES 

   The GND wires are OK. Go to step 7.

   NO 

   Repair an open or high resistance in the ground wire or poor ground (G502).

7. Open wire check (B-CAN lines)

   - 1. Disconnect the following connector.

   KEYLESS ACCESS CONTROL UNIT CONNECTOR B (28P)

   - 2. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Gauge control module connector A (32P): disconnected Keyless access control unit connector B (28P): disconnected
   Test circuit	B-CAN_H
   Test point 1	Keyless access control unit connector B (28P) No. 6 (PNK)
   Test point 2	Gauge control module connector A (32P) No. 30 (PNK)

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

   Is there continuity?

   YES 

   An open or poor connection in the B-CAN_L wire between the keyless access control unit and the gauge control module.

   NO 

   An open or poor connection in the B-CAN_H wire between the keyless access control unit and the gauge control module.

8. Open wire check (B-CAN lines)

   - 1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Disconnect the following connectors.

   GAUGE CONTROL MODULE CONNECTOR A (32P)

   KEYLESS ACCESS CONTROL UNIT CONNECTOR B (28P)

   - 3. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Gauge control module connector A (32P): disconnected Keyless access control unit connector B (28P): disconnected
   Test circuit	B-CAN_H
   Test point 1	Keyless access control unit connector B (28P) No. 6 (PNK)
   Test point 2	Gauge control module connector A (32P) No. 30 (PNK)

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

   Is there continuity?

   YES 

   An open or poor connection in the B-CAN_L wire between the keyless access control unit and the gauge control module.

   NO 

   An open or poor connection in the B-CAN_H wire between the keyless access control unit and the gauge control module.