DTC Troubleshooting: U128D
DTC U128D: MICU lost communication with gauge control module
DTC Description
DTC
U128D MICU lost communication with gauge control module
  

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

1.
Problem verification:

Problem verification
?1.
Turn the vehicle to the ON mode.

?2.
Clear the DTCs with the HDS.


?3.
Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

?4.
Wait for at least 6 seconds.

?5.
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):

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:

Fuse check
?1.
Check the following fuse.
Fuse
No. B29 (10 A)
Location
Under-hood fuse/relay box

Is the fuse OK?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Replace the fuse. If the fuse blows again, repair a short to ground in the No. B29 (10 A) fuse circuit.?
4.
Open wire check (+B BACK UP line):

Open wire check (+B BACK UP line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Gauge control module 32P connector

?3.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
Gauge control module 32P connector: disconnected
Test point 1
Gauge control module 32P connector No. 16
Test point 2
Body ground

Is there battery voltage?

     
YES
     
     
     
Repair an open or high resistance in the ground wire or poor ground (G401).?
     
NO
     
     
     
Repair an open or high resistance in the wire.?
5.
Open wire check (B-CAN_H line):

Open wire check (B-CAN_H line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connectors.
Under-dash fuse/relay box connector G (10P)
Gauge control module 32P connector

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
Under-dash fuse/relay box connector G (10P): disconnected
Gauge control module 32P connector: disconnected
Test point 1
Under-dash fuse/relay box connector G (10P) No. 3
Test point 2
Gauge control module 32P connector No. 23

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.?
6.
Open wire check (B-CAN_L line):

Open wire check (B-CAN_L line)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
Under-dash fuse/relay box connector G (10P): disconnected
Gauge control module 32P connector: disconnected
Test point 1
Under-dash fuse/relay box connector G (10P) No. 2
Test point 2
Gauge control module 32P connector No. 23

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.?