DTC U128D: Backup Control Unit Lost Communication With Gauge Control Module
- 1. Problem verification:
- 1. Clear the DTCs with the HDS.
- 2. Press the engine start/stop button to select the OFF mode and then the ON mode.
- 3. Wait for at least 6 seconds.
- 4. Check for DTCs with the HDS.
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 (tach) 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 fuse.
Fuse No. A29 (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. A29 (10 A) fuse circuit.
- 4. Open wire check (+B_BACK_UP line):
- 1. Press the engine start/stop button to select the OFF mode.
- 2. Disconnect the following connector.
Gauge control module (tach) 32P connector - 3. Measure the voltage between test points 1 and 2.
Test condition OFF mode Gauge control module (tach) 32P connector: disconnected Test circuit +B_BACK_UP Test point 1 Gauge control module (tach) 32P connector No. 1 (WHT) Test point 2 Body ground Is there battery voltage?
YES
The +B_BACK_UP wire is OK. Go to step 5.
NO
Repair an open or high Ω in the wire.
- 5. Open wire check (IG1_METER line):
- 1. Press the engine start/stop button to select the ON mode.
- 2. Measure the voltage between test points 1 and 2.
Test condition ON mode Gauge control module (tach) 32P connector: disconnected Test circuit IG1_METER Test point 1 Gauge control module (tach) 32P connector No. 17 (BRN) Test point 2 Body ground Is there battery voltage?
YES
The IG1_METER wire is OK. Go to step 6.
NO
Repair an open or high Ω in the wire.
- 6. Open wire check (GND lines):
- 1. Press the engine start/stop button to select the OFF mode.
- 2. Check for continuity between test points 1 and 2 individually.
Test condition OFF mode Gauge control module (tach) 32P connector: disconnected Test circuit GND Test point 1 Gauge control module (tach) 32P connector No. 4 (BLK) Test point 2 Body ground Test circuit GND Test point 1 Gauge control module (tach) 32P connector No. 32 (BRN) Test point 2 Body ground Is there continuity?
YES
The GND wires are OK. Go to step 7.
NO
Repair an open or high Ω in the ground wire or poor ground (G502/G503).
- 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 OFF mode Gauge control module (tach) 32P connector: disconnected Key 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 (tach) 32P connector No. 30 (PNK) Is there continuity?
YES
An open or poor connection in the B_CAN-L wire between the MICU and the gauge control module (tach).
NO
An open or poor connection in the B_CAN-H wire between the MICU and the gauge control module (tach).
- 8. Open wire check (B_CAN lines):
- 1. Press the engine start/stop button to select the OFF mode.
- 2. Disconnect the following connectors.
Gauge control module (tach) 32P connector Keyless access control unit connector B (28P) - 3. Check for continuity between test points 1 and 2.
Test condition OFF mode Gauge control module (tach) 32P connector: disconnected Key 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 (tach) 32P connector No. 30 (PNK) Is there continuity?
YES
An open or poor connection in the B_CAN-L wire between the MICU and the gauge control module (tach).
NO
An open or poor connection in the B_CAN-H wire between the MICU and the gauge control module (tach).