Lexus IS250 · Service Manual CRUISE CONTROL SYSTEM

U0235

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 millimeter wave radar sensor transmits information about the vehicle in front to the distance control ECU (cruise control ECU).
DTC No.
 DTC Detection Condition
 Trouble Area
U0235
 The ECM detects a communication error signal (from the millimeter wave radar sensor to the distance control ECU) 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

E106783E04

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. E108175E08
    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
    J17-22 (LRDD) - B9-3 (LRDD)
    		 Always
    		 Below 1 Ω
    J17-13 (IGB) - B9-5 (IGB)
    		 Always
    		 Below 1 Ω
    J17-22 (LRDD) - 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. I034909E23
    Disconnect the millimeter wave radar sensor connector.

  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
    J17-22 (LRDD) - J17-10 (SGND)
    		 Engine switch on (IG)
    		 4.5 to 5.5 V



NG
REPLACE DISTANCE CONTROL ECU
OK


3. CHECK MILLIMETER WAVE RADAR SENSOR

  1. I039260E12
    Reconnect the millimeter wave radar sensor connector.

  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

  1. E109730E01
    Check the signal waveform between terminal LRDD (B9-3) 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., 10 msec./DIV.
    2. Condition: Engine switch on (IG)



 NG
REPLACE MILLIMETER WAVE RADAR SENSOR
OK

END (INTERMITTENT PROBLEM IS PRESENT)


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