DTC U128D (81): Lost Communication with Gauge Control Module (ECT message); DTC U128D (83): Climate Control Unit Lost Communication with Gauge Control Module (VSP message)
| DTC Description | DTC |
|---|---|
| U128D Lost communication with gauge control module (climate control unit) |
- 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. Do the Self-Diagnostic Function with the HDS or the climate control unit - Refer to: How to Troubleshoot the Body ElectricalHow to Troubleshoot the Climate Control System .
4. Check for DTCs.
DTC Description DTC U128D Lost communication with gauge control module (climate control unit) Is DTC U128D or 81 and/or 83 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 lines):
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 3.
NO
Go to step 4.
- 3. Open wire check (B-CAN_H line):
1. Turn the vehicle to the OFF (LOCK) mode.
2. Disconnect the following connectors.
Gauge control module connector A (32P) Climate control unit 32P connector 3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Gauge control module connector A (32P): disconnected Climate control unit 32P connector: disconnected Test point 1 Gauge control module connector A (32P) No. 30 Test point 2 Climate control unit 32P connector No. 16 Is there continuity?
YES
Repair an open or poor connection in the B-CAN_L wire between the climate control unit and the gauge control module.
NO
Repair an open or poor connection in the B-CAN_H wire between the climate control unit and the gauge control module.
- 4. Fuse check:
1. Turn the vehicle to the OFF (LOCK) mode.
2. Check the following fuses.
Fuse No. A29 (10 A) Location Under-hood fuse/relay box Fuse No. B5 (10 A) Location Under-dash fuse/relay box Are the fuses OK?
YES
Go to step 5.
NO
Replace the fuse, and recheck. If the fuse blows again, repair a short in the No. A29 (10 A) or No. B5 (10 A) fuse circuit.
- 5. Open wire check (+B BACK UP line):
1. Disconnect the following connector.
Gauge control module connector A (32P) 2. Measure the voltage between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Gauge control module connector A (32P): disconnected Test point 1 Gauge control module connector A (32P) No. 1 Test point 2 Body ground Is there battery voltage?
YES
The +B BACK UP wire is OK. Go to step 6.
NO
Repair an open in the +B BACK UP wire.
- 6. 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 point 1 Gauge control module connector A (32P) No. 17 Test point 2 Body ground Is there battery voltage?
YES
The IG1 METER wire is OK. Go to step 7.
NO
Repair an open in the IG1 METER wire.
- 7. 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 point 1 Gauge control module connector A (32P) No. 4 Test point 2 Body ground Test point 1 Gauge control module connector A (32P) No. 32 Test point 2 Body ground Is there continuity?
YES
The GND wires are OK. Go to step 8.
NO
Check for an open in the wire(s) between the gauge control module and body ground. If the wire(s) is OK, check for poor ground at G502.
- 8. Open wire check (B-CAN_H line):
1. Disconnect the following connector.
Climate control unit 32P connector 2. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Gauge control module connector A (32P): disconnected Climate control unit 32P connector: disconnected Test point 1 Gauge control module connector A (32P) No. 30 Test point 2 Climate control unit 32P connector No. 16 Is there continuity?
YES
Repair an open or poor connection in the B-CAN_L wire between the climate control unit and the gauge control module.
NO
Repair an open or poor connection in the B-CAN_H wire between the climate control unit and the gauge control module.
