DTC U128D (Keyless Access Backup Control Unit)

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

NOTE:  The DTC may be stored due to the grounding failure or the power source failure at the transmitting control unit (the grounding inspection and the power source inspection on each control unit are required prior to this checking process).

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.

   -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 poor connections or loose terminals at the transmitting control units, and keyless access control unit.

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 control unit connector C (20P)

   -3. Disconnect the transmitting control unit connector.

   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 mode.

   DTC	CIRCUIT NAME	RECEIVING CONTROL UNIT	TRANSMITTING CONTROL UNIT
   U128D Backup control unit lost communication with gauge control module	B-CAN_H	Keyless access control unit connector C (20P) No. 1	Gauge control module 32P connector No. 23
   	B-CAN_L	Keyless access control unit connector C (20P) No. 11	Gauge control module 32P connector No. 24

   Is there continuity?

   YES 

   The B-CAN_H and B-CAN_L wires are OK. Go to step 3.

   NO 

   Repair an open in the B-CAN_H and/or B-CAN_L wires between the receiving control unit and the transmitting control unit.

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

   -1. Reconnect the following connectors.

   Keyless access control unit connector C (20P) Gauge control module 32P connector

   -2. Turn the vehicle to the ON mode.

   -3. Clear the DTCs with the HDS.

   -4. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

   -5. Wait for at least 6 seconds.

   -6. Check for DTCs with the HDS.

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

   Is DTC U128D indicated?

   YES 

   Replace the keyless access control unit .

   NO 

   The keyless access control unit is OK at this time, replace the gauge control module. (Refer to the DTC code shown on the display, and then replace the control unit based on the instructions in the table below.)

   DTC	TRANSMITTING CONTROL UNIT
   U128D Backup control unit lost communication with gauge control module	Gauge control module