DTC    U0122    Lost Communication with Vehicle Dynamics Control Module

DTC    U0123    Lost Communication with Yaw Rate Sensor Module

DTC    U0126    Lost Communication with Steering Angle Sensor Module

DTC    U0140    Lost Communication with Main Body ECU

DTC    U0151    Lost Communication with Airbag ECU

DTC    U0293    Lost Communication with HV ECU

DTC    U1100    Lost Communication with Seat Belt Control ECU

DTC    U1104    Lost Communication with Driving Support ECU

for Preparation Click here


DESCRIPTION

  1. The driving support ECU uses the millimeter wave radar sensor to detect obstacles in front of the vehicle. Based on this information, the driving support ECU sends pre-crash control operation signals. These DTCs are stored when a communication malfunction occurs between the sensors and ECUs that detect crashes, or between ECUs that perform the pre-crash control.
  1. The driving support ECU sends vehicle speed and vehicle condition information to the millimeter wave radar sensor. The millimeter wave radar sensor then sends information on the presence, distance, and relative speed of objects ahead to the driving support ECU. The driving support ECU sends this information to the ECM and performs pre-crash system (DTC U1104).

    DTC No.
    		DTC Detection Condition
    		Trouble Area
    U0122
    1. When the power switch is on (IG), a communication error between the brake booster with master cylinder (skid control ECU) and the driving support ECU is detected for approx. 3 seconds.
    2. When the power switch is on (IG), a communication error between the skid control ECU assembly and the seat belt control ECU is detected for approx. 3 seconds.
    1. Brake booster with master cylinder (skid control ECU)
    2. CAN communication system
    3. Driving support ECU
    4. Wire harness or connector
    U0123
    		When the power switch is on (IG), a communication error between the yaw rate sensor and the driving support ECU is detected for approx. 1 second.
    1. Yaw rate sensor
    2. CAN communication system
    3. Driving support ECU
    U0126
    		When the power switch is on (IG), a communication error between the steering angle sensor and the driving support ECU is detected for approx. 1 second.
    1. Steering angle sensor
    2. CAN communication system
    3. Driving support ECU
    U0140
    		When the power switch is on (IG), communication stop between the main body ECU and seat belt control ECU continues for 6 seconds or more.
    1. Main body ECU
    2. CAN communication system
    3. Seat belt control ECU
    4. Wire harness or connector
    U0151
    		When the power switch is on (IG), communication stop between the center airbag sensor and seat belt control ECU continues for 6 seconds or more.
    1. Center airbag sensor
    2. CAN communication system
    3. Seat belt control ECU
    4. Wire harness or connector
    U0293
    1. When the power switch is on (IG), a communication error between the power management control ECU and brake booster with master cylinder (skid control ECU) is detected for approx. 1 second.
    2. When the power switch is on (IG), a communication error between the power management control ECU and driving support ECU is detected for approx. 1 second.
    1. Power management control ECU
    2. Brake booster with master cylinder (skid control ECU)
    3. CAN communication system
    4. Driving support ECU
    U1100
    		When the power switch is on (IG), a communication error between the seat belt control ECU and the driving support ECU is detected for approx. 1 second.
    1. Seat belt control ECU
    2. CAN communication system
    3. Driving support ECU
    U1104
    1. When the power switch is on (IG), a communication error between the driving support ECU and the millimeter wave radar sensor is detected for approx. 1 second.
    2. When the power switch is on (IG), a communication error between the driving support ECU and the power management control ECU is detected for approx. 1 second.
    3. When the power switch is on (IG), a communication error between the driving support ECU and seat belt control ECU is detected for approx. 1 second.
    1. Communication circuit
    2. Millimeter wave radar sensor
    3. Driving support ECU
    4. CAN communication system
    5. Wire harness or connector

WIRING DIAGRAM


B265918E02


INSPECTION PROCEDURE

NOTICE:
  1. When replacing the millimeter wave radar sensor with a new one, make sure to perform Adjust Millimeter Wave Radar Sensor Assembly (Click here).
  2. Confirm that the connector is securely connected, as a partially connected connector is suspected for the cause of this DTC.

1.CHECK DTC OUTPUT

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the intelligent tester on.

  1. Enter the following menus: Body / Pre-Crash and Pre-Crash 2 / DTC.

  1. Check for DTCs.

    Result:
    Result
    		Proceed to
    DTC U1104 is output
    		A
    DTC U1104 is not output
    		B



B
GO TO CAN COMMUNICATION SYSTEM (Click here)
A


2.CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU - MILLIMETER WAVE RADAR SENSOR)

  1. Disconnect the driving support ECU and millimeter wave radar sensor connectors.

  1. Measure the resistance according to the value(s) in the table below.

Standard Resistance:
Tester Connection
Condition
Specified Condition
H5-38 (LRRD) - A2-4 (LRRD)
Always
Below 1 Ω
A2-4 (LRRD) - Body ground
Always
10 kΩ or higher
H5-38 (LRRD) - Body ground
Always
10 kΩ or higher

  1. Reconnect the driving support ECU and millimeter wave radar sensor connectors.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVING SUPPORT ECU - MILLIMETER WAVE RADAR SENSOR)
OK


3.CHECK CAN COMMUNICATION SYSTEM

  1. Clear the DTCs (Click here).

  1. Recheck for DTCs.

    OK:
    CAN communication system DTC is not output.



NG
GO TO CAN COMMUNICATION SYSTEM (Click here)
OK


4.CHECK MILLIMETER WAVE RADAR SENSOR (IGB VOLTAGE)


    E181639E11

  1. Disconnect the millimeter wave radar sensor connector.

  1. Turn the power switch on (IG).

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A2-5 (IGB) - Body ground
    		Power switch on (IG)
    		11 to 14 V

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Millimeter Wave Radar Sensor)

  1. Reconnect the millimeter wave radar sensor connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (IGB CIRCUIT)
OK


5.CHECK MILLIMETER WAVE RADAR SENSOR (SGND CIRCUIT)


    E181639E12

  1. Disconnect the millimeter wave radar sensor connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A2-2 (SGND) - Body ground
    		Always
    		Below 1 Ω

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Millimeter Wave Radar Sensor)

  1. Reconnect the millimeter wave radar sensor connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (SGND CIRCUIT)
OK


6.CHECK DRIVING SUPPORT ECU (LRRD OUTPUT VOLTAGE)


    E165597E22

  1. Turn the power switch on (IG).

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    H5-38 (LRRD) - Body ground
    		Power switch on (IG)
    		4.5 to 5.5 V

    Text in Illustration 
    *a
    		Component with harness connected
    (Driving Support ECU)



NG
REPLACE DRIVING SUPPORT ECU (Click here)
OK


7.REPLACE MILLIMETER WAVE RADAR SENSOR

  1. Replace the millimeter wave radar sensor (Click here).

  1. Adjust the millimeter wave radar sensor (Click here).


NEXT


8.CHECK DTC OUTPUT

  1. Clear the DTCs (Click here).

  1. Turn the cruise control main switch on.

  1. Drive the vehicle at the required speed (45 km/h (28 mph) or higher).

  1. Check if the same DTC is output (Click here).

    Result:
    Result
    		Proceed to
    DTC U1104 is not output
    		A
    DTC U1104 is output
    		B



B
REPLACE DRIVING SUPPORT ECU (Click here)
A

END