Dtc U1102 Lost Communication With Radar Sensor

Cruise Control System. Lexus Is250, Is220D. Gse20 Ale20
Cruise Control. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

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

CHECK DISTANCE CONTROL ECU

CHECK MILLIMETER WAVE RADAR SENSOR

DTC U1102 Lost Communication with Radar Sensor


DESCRIPTION

The millimeter wave radar sensor and distance control ECU (cruise control ECU) transmit the data for general vehicle control and diagnosis function along the communication line. The distance control ECU (cruise control ECU) determines the curve radius information based on signals from the steering wheel and yaw rate sensor. The distance control ECU (cruise control ECU) transmits the current vehicle speed and curve radius information to the millimeter wave radar sensor.

DTC No.
DTC Detection Condition
Trouble Area
U1102
The ECM detects a communication error signal (from the distance control ECU (cruise control ECU) to the millimeter wave radar sensor) for 0.15 sec. or more while the dynamic radar cruise control is in operation
  1. Communication circuit
  2. Millimeter wave radar sensor
  3. Distance control ECU (Cruise control ECU)

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Cruise Control.Cruise Control System. Dtc U1102 Lost Communication With Radar Sensor


INSPECTION PROCEDURE

NOTICE:
  1. When the distance control ECU is replaced with a new one, initialization must be performed (Click here).
  2. When the millimeter wave radar sensor is replaced with a new one, adjustment of the radar sensor beam axis must be performed (Click here).
1.CHECK HARNESS AND CONNECTOR (DISTANCE CONTROL ECU - MILLIMETER WAVE RADAR SENSOR)


    Lexus Is250, Is220D. Gse20 Ale20.Cruise Control.Cruise Control System. Dtc U1102 Lost Communication With Radar Sensor

  1. Disconnect the distance control 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
    J17-23 (LRRD) - B9-4 (LRRD)
    		Always
    		Below 1 Ω
    J17-13 (IGB) - B9-5 (IGB)
    		Always
    		Below 1 Ω
    J17-23 (LRRD) - Body ground
    		Always
    		10 kΩ or higher
    J17-13 (IGB) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2.CHECK DISTANCE CONTROL ECU


    Lexus Is250, Is220D. Gse20 Ale20.Cruise Control.Cruise Control System. Dtc U1102 Lost Communication With Radar Sensor

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    J17-13 (IGB) - Body ground
    		Engine switch on (IG)
    		10 to 14 V


NG
REPLACE DISTANCE CONTROL ECU
OK


3.CHECK MILLIMETER WAVE RADAR SENSOR


    Lexus Is250, Is220D. Gse20 Ale20.Cruise Control.Cruise Control System. Dtc U1102 Lost Communication With Radar Sensor

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    B9-5 (IGB) - Body ground
    		Engine switch on (IG)
    		10 to 14 V


    Lexus Is250, Is220D. Gse20 Ale20.Cruise Control.Cruise Control System. Dtc U1102 Lost Communication With Radar Sensor

  1. Check the signal waveform between terminal LRRD (B9-4) of the millimeter wave radar sensor and body ground.

    OK:
    A waveform similar to that in the illustration on the left is output.
    HINT:
    1. Gauge set: 2 V/DIV., 5 msec./DIV.
    2. Condition: Engine switch on (IG)


NG
REPLACE MILLIMETER WAVE RADAR SENSOR
OK

END (INTERMITTENT PROBLEM IS PRESENT)