DTC    U1102    Lost Communication With Radar Sensor

for Preparation Click here


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 presumed R information based on the signal from the steering wheel and yaw rate sensor. The distance control ECU (cruise control ECU) transmits the current vehicle speed and presumed R information to the millimeter wave radar sensor.

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

WIRING DIAGRAM


E109063E02


INSPECTION PROCEDURE

NOTICE:
  1. When the distance control ECU is replaced with a new one, initialization must be performed (for LHD, Click here; for RHD, 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 WIRE HARNESS (DISTANCE CONTROL ECU - MILLIMETER WAVE RADAR SENSOR)


    E108175E06

  1. Disconnect the L13 distance control ECU connector.

  1. Disconnect the B8 millimeter wave radar sensor connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    L13-23 (LRRD) - B8-4 (LRRD)
    		Always
    		Below 1 Ω
    L13-13 (IGB) - B8-5 (IGB)
    		Always
    		Below 1 Ω
    L13-23 (LRRD) - Body ground
    		Always
    		10 kΩ or higher
    L13-13 (IGB) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE WIRE HARNESS AND CONNECTOR
OK


2.CHECK DISTANCE CONTROL ECU


    I034909E15

  1. Measure the voltage of the connector.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    L13-13 (IGB) - Body ground
    		Engine switch on (IG)
    		10 to 16 V



NG
REPLACE DISTANCE CONTROL ECU
OK


3.CHECK MILLIMETER WAVR RADAR SENSOR


    I039260E06

  1. Measure the voltage of the connector.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    B8-5 (IGB) - Body ground
    		Engine switch on (IG)
    		10 to 16 V



    E109731E01

  1. Check the signal waveform between terminal LRRD (B8-4) of the millimeter wave radar sensor and body ground.

    OK:
    Waveform similar to that in the illustration 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)