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 U0235: Lost Communication with Cruise Control Front Distance Range Sensor; DTC U1100: Lost Communication with Seat Belt Control ECU; DTC U1104: Lost Communication with Driving Support ECU: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Pre-Collision and Pre-Collision 2 / Trouble Codes.
5. Check for DTCs.
   RESULT
   
   

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

B → See step   8 

A: Go to next step 

1. Disconnect the A44 driving support ECU and A36 millimeter wave radar sensor connectors.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A44-38 (LRRD) - A36-4 (LRRD)	Always	Below 1 Ω
   A36-4 (LRRD) - Body ground	Always	10 kΩ or higher
   A44-38 (LRRD) - Body ground	Always	10 kΩ or higher

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

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the A36 millimeter wave radar sensor connector.
   Fig 1: Measuring Voltage Of Millimeter Wave Radar Sensor (IGB Voltage)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Turn the ignition switch to ON.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A36-5 (IGB) - Body ground	Ignition switch ON	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Millimeter Wave Radar Sensor)

4. Reconnect the millimeter wave radar sensor connector.

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

OK: Go to next step 

1. Disconnect the A36 millimeter wave radar sensor connector.
   Fig 2: Measuring Resistance Of Millimeter Wave Radar Sensor (SGND Circuit)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A36-2 (SGND) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Millimeter Wave Radar Sensor)

3. Reconnect the millimeter wave radar sensor connector.

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

OK: Go to next step 

1. Turn the ignition switch to ON.
   Fig 3: Inspecting Driving Support ECU (LRRD Output Voltage)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A44-38 (LRRD) - Body ground	Ignition switch ON	4.5 to 5.5 V

   TEXT IN ILLUSTRATION
   
   

   *1	Component with harness connected (Driving Support ECU)

NG → See step   9 

OK: Go to next step 

1. Replace the millimeter wave radar sensor. Refer to REMOVAL .
2. Adjust the millimeter wave radar sensor. Refer to ADJUSTMENT .

NEXT: Go to next step 

1. Clear the DTCs. Refer to DTC CHECK / CLEAR .
2. Check for DTCs. Refer to DTC CHECK / CLEAR .
   RESULT
   
   

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

B → See step   9 

A → END