DTC U128D (MICU (Multiplex Integrated Control Unit)) (2016 2017 2018 2019 2020)

DTC U128D  : MICU Lost Communication With Gauge Control Module

DTC (MICU)

NOTE:  If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A .

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 MICU 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 BODY ELECTRICAL SYSTEM SELECT menu, and then select DATA LIST other than GAUGES.

   Does the DATA LIST appear?

   YES 

   Go to step 5.

   NO 

   Go to step 3.

3. Fuse check

   -1. Check the following fuses.

   Fuse	No. C16 (10 A)
   Location	Under-hood fuse/relay box

   Fuse	No. D11 (10 A)
   Location	Driver's 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. C16 (10 A) and/or No. D11 (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 (PNK)
   Test point 2	Body ground

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

   Is there battery voltage?

   YES 

   Repair an open or high resistance in the ground wire or poor ground (G501).

   NO 

   Repair an open or high resistance in the wire.

5. Open wire check (B-CAN_H line)

   -1. Disconnect the following connectors.

   Gauge control module connector A (32P)

   Driver's under-dash fuse/relay box connector G (16P)

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

   Test condition	Vehicle OFF (LOCK) mode Gauge control module connector A (32P): disconnected Driver's under-dash fuse/relay box connector G (16P): disconnected
   Test circuit	B-CAN_H
   Test point 1	Driver's under-dash fuse/relay box connector G (16P) No. 2 (RED)
   Test point 2	Gauge control module connector A (32P) No. 25 (RED)

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

   Is there continuity?

   YES 

   The B-CAN_H wire is OK. Go to step 6.

   NO 

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

6. Open wire check (B-CAN_L line)

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

   Test condition	Vehicle OFF (LOCK) mode Gauge control module connector A (32P): disconnected Driver's under-dash fuse/relay box connector G (16P): disconnected
   Test circuit	B-CAN_L
   Test point 1	Driver's under-dash fuse/relay box connector G (16P) No. 1 (WHT)
   Test point 2	Gauge control module connector A (32P) No. 26 (WHT)

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

   Is there continuity?

   YES 

   The B-CAN_L wire is OK. Replace the gauge control module .

   NO 

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