DTC U128D (Keyless Access Backup Control Unit)

DTC U128D  : Backup control unit lost communication with gauge control module

DTC (Backup Control Unit)

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.

   Clear DTCs

   -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 Backup 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. Open wire check (B-CAN_H, B-CAN_L lines)

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

   -2. Disconnect the receiving control unit connector.

   Keyless access/TPMS control unit connector C (20P)

   -3. Disconnect the transmitting control unit connectors.

   Gauge control module 32P connector

   -4. Check for continuity between the receiving control unit and the transmitting control unit on the B-CAN_H circuit and the B-CAN_L circuit as specified in the table while in the vehicle OFF (LOCK) mode.

   DTC	CIRCUIT NAME	RECEIVING CONTROL UNIT	TRANSMITTING CONTROL UNIT
   U128D	B-CAN_H	Keyless access/TPMS control unit connector C (20P) No. 1	Gauge control module 32P connector No. 26
   	B-CAN_L	Keyless access/TPMS control unit connector C (20P) No. 11	Gauge control module 32P connector No. 27

   Is there continuity?

   YES 

   The B-CAN_L to B-CAN_H wire is OK. Go to step 3.

   NO 

   Repair an open or high resistance in the wire(s).

3. Determine possible failure area (the receiving control unit or the transmitting control unit)

   -1. Reconnect all connectors.

   -2. Clear the DTCs with the HDS.

   Clear DTCs

   -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 Backup control unit lost communication with gauge control module

   Is DTC U128D indicated?

   YES 

   Check for loose terminals and poor connections in the keyless access/TPMS control unit connector. Check is OK, replace the keyless access/TPMS control unit .

   NO 

   The keyless access/TPMS control unit is OK at this time. Replace the transmitting control unit.

   (Refer to the DTC code shown on the display, and then replace the control unit based on the instructions in the chart below.)

   DTC	TRANSMITTING CONTROL UNIT
   U128D	Replace the gauge control module