DTC U1102 Lost Communication with Radar Sensor

DESCRIPTION

The distance control ECU sends the vehicle speed and estimated curve information to the millimeter wave radar sensor. The millimeter wave radar sensor sends information about whether another vehicle is present in front of the vehicle, the distance between the vehicles, relative speed, etc. to the distance control ECU. The distance control ECU sends this information to the ECM and performs control of cruise control.

DTC Code	DTC Detection Condition	Trouble Area
U1102	The vehicle speed is 50 km/h (30 mph) or more with the cruise control main switch on (vehicle-to-vehicle distance control mode) and the data sent from the distance control ECU to the millimeter wave radar sensor is abnormal.	Distance control ECU Harness or connector Millimeter wave radar sensor

WIRING DIAGRAM

Dtc U1102 Lost Communication With Radar Sensor. CRUISE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

INSPECTION PROCEDURE

NOTICE:

When the distance control ECU is replaced with a new one, initialization must be performed ().

When the millimeter wave radar sensor is replaced with a new one, adjustment of the radar sensor beam axis must be performed ().

As it is possible that this DTC was stored due to a bad connection of a connector, make sure to check that each connector is connected securely.

1.CHECK HARNESS AND CONNECTOR (DISTANCE CONTROL ECU - MILLIMETER WAVE RADAR SENSOR)

Dtc U1102 Lost Communication With Radar Sensor. CRUISE CONTROL. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

Disconnect the A56 millimeter wave radar sensor connector.

Disconnect the E108 distance control ECU connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A56-3 (LRDD) - E108-22 (LRDD)	Always	Below 1 Ω
E108-22 (LRDD) - Body ground	Always	10 kΩ or higher
A56-2 (SGND) - Body ground	Always	10 kΩ or higher
E108-10 (SGND) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2.REPLACE DISTANCE CONTROL ECU

Replace the distance control ECU with a new one ().

Perform initialization ().

NEXT

3.CHECK DTC (DYNAMIC RADAR CRUISE CONTROL SYSTEM)

Using the intelligent tester, enter the following menus: Powertrain / Radar Cruise / Trouble Code.

Clear the DTCs ().

Perform the following to make sure the DTC detection conditions are met.

HINT:

If the detection conditions are not met, the system cannot detect the malfunction.

Drive the vehicle at a speed of 50 km/h (30 mph) or more.

Turn the cruise control main switch on.

Push the -SET switch to activate the dynamic radar cruise control.

Check for DTCs ().

OK:
DTC U1102 is not output.

REPLACE MILLIMETER WAVE RADAR SENSOR ()

END (DISTANCE CONTROL ECU IS DEFECTIVE)