Lexus IS250 · Service Manual CRUISE CONTROL SYSTEM

U1102

Diagnostic trouble codes

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

E106783E05

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)

  1. E108175E09
    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

  1. I034909E21
    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

  1. I039260E13
    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

  1. E109731E01
    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)


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