DTC U1102: Lost Communication with Radar Sensor: Procedure

1. Disconnect the distance control ECU connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

2. Disconnect the millimeter wave radar sensor assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   J17-23 (LRRD) - B9-4 (LRRD)	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   J17-23 (LRRD) or B9-4 (LRRD) - Body ground	Always	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Distance Control ECU)
   *2	Front view of wire harness connector (to Millimeter Wave Radar Sensor Assembly)

4. Reconnect the distance control ECU connector.
5. Reconnect the millimeter wave radar sensor assembly connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (DISTANCE CONTROL ECU - MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 

OK: Go to next step 

1. Disconnect the distance control ECU connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   J17-10 (SGND) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Distance Control ECU)

3. Reconnect the distance control ECU connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (DISTANCE CONTROL ECU - BODY GROUND) 

OK: Go to next step 

1. Replace the distance control ECU. Refer to REMOVAL [08/2012 - ] .

NEXT: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Clear the DTCs. Refer to DTC CHECK/CLEAR [08/2012 - ] .
5. Perform the following to make sure that the DTC detection conditions are met.

   HINT: 

   If the detection conditions are not met, the malfunction cannot be detected.

   1. Drive the vehicle at a speed of 50 km/h (30 mph) or more.
   2. Turn the cruise control main switch on.
6. Enter the following menus: Powertrain / Radar Cruise / Trouble Codes.
7. Read the DTCs. Refer to DTC CHECK/CLEAR [08/2012 - ] .

   Result

   Result	Proceed to
   DTC is not output	A
   DTC U1102 is output	B

B → See step   5 

A → END