DTC U128D (Telematics Control Unit)

ElectronicCircuitSchematics-button DTC U128D  : Telematics Control Unit Lost Communication with Gauge Control Module

DTCs (Telematics System)

NOTE: 

• If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode B - Control Unit Not Communicating or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode 1 and Test Mode 2 (without the HDS) .
• According to the detected DTC, check for the power circuit and the ground circuit of the control unit which cannot communicate with the telematics control unit.
• Check the connectors for poor connections or loose terminals.

1. Problem verification

   -1. Clear the DTCs with the HDS.

   -2. Turn the vehicle to the OFF (LOCK) mode.

   -3. Open the driver's door, and wait more than 1 minute.

   -4. Turn the vehicle to the ON mode.

   -5. Wait for at least 6 seconds.

   -6. Check for DTCs with the HDS.

   DTC Description	DTC
   U128D Telematics control unit lost communication with Gauge control module

   Is DTC U128D indicated?

   YES 

   The failure is duplicated, go to step 2.

   NO 

   Intermittent failure, the system is OK at this time.

2. Open wire check (B-CAN_H line, B-CAN_L line)

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

   -2. Open the driver's door, and wait more than 1 minute.

   -3. Disconnect the receiving control unit connector.

   Telematics control unit connector A (32P)

   -4. Disconnect the transmitting control unit connector(s).

   Refer to the DTC shown on the display, then disconnect the connector(s) based on the instructions (see table).

   DTC	Connector
   U128D	Gauge control module connector A (32P)

   -5. 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.

   Test condition	Vehicle OFF (LOCK) mode
   	Telematics control unit connector A (32P): disconnected
   	Transmitting control unit connector(s) for indicated DTCs: disconnected

   DTC	Circuit name	Receiving control unit		Transmitting control unit
   		Connector	Terminal	Connector	Terminal
   U128D	B-CAN_L	Telematics control unit connector A (32P)	No. 22	Gauge control module connector A (32P)	No. 31
   	B-CAN_H		No. 23		No. 30

   Is there continuity?

   YES 

   The B-CAN_H wire and the B-CAN_L wire are OK.Refer to the DTC shown on the display, then replace the control unit based on the instructions (see table).

   DTC	Operation for transmitting control unit
   U128D	Gauge control module

   NO 

   Repair an open in the B-CAN_H wire and/or the B-CAN_L wire.