LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2013 >> CT 200h Base >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Communication Devices >> Can Communication System (Diagnostic Codes & Circuit Tests) >> Can Communication System >> DTC U1002: Lost Communication with Gateway Module (Sensor Bus); DTC U0235: Lost Communication with Cruise Control Front Distance Range Sensor >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC U1002: Lost Communication with Gateway Module (Sensor Bus); DTC U0235: Lost Communication with Cruise Control Front Distance Range Sensor: Procedure

  1. CHECK SENSOR BUS LINES 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Measure the resistance according to the value(s) in the table below.
      Fig 1: Identifying H5 Harness Connector Terminals
      GTY416881Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      H5-40 (CA1P) - H5-18 (CA1N) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Below 54 Ω:
      Short circuit between bus lines
      70 Ω or more:
      Open circuit in a main bus line
      H5-40 (CA1P) - H5-25 (GND) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω:
      CANH ground short
      H5-18 (CA1N) - H5-25 (GND) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω:
      CANL ground short
      TEXT IN ILLUSTRATION

      *a Component with harness connected
      (Driving Support ECU Assembly)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      H5-40 (CA1P) - H5-30 (B) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ:
      CANH +B short
      H5-18 (CA1N) - H5-30 (B) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ:
      CANL +B short

      Result

      Result Proceed to
      OK A
      • Open circuit in CAN main bus line
      • Short circuit between bus lines
      		 B
      • Ground short
      • +B short
      		 C

    B → See step   3 

    C → See step   5 

    A: Go to next step 

  2. CHECK FOR POWER SOURCE CIRCUIT (MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 
    1. Check the millimeter wave radar sensor assembly power source circuit. Refer to Millimeter Wave Radar Sensor Power Source Circuit .

    NG → REPAIR OR REPLACE CORRESPONDING AREA 

    OK → See step   7 

  3. CHECK FOR OPEN IN SENSOR BUS MAIN LINES (DRIVING SUPPORT ECU ASSEMBLY) 
    1. Disconnect the H5 driving support ECU assembly connector.
      Fig 2: Identifying H5 Harness Connector Terminals
      GTY417638Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Driving Support ECU Assembly)
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H5-40 (CA1P) - H5-18 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

    NG → See step   4 

    OK → See step   7 

  4. CHECK FOR OPEN IN SENSOR BUS MAIN LINES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 
    1. Reconnect the H5 driving support ECU assembly connector.
    2. Disconnect the A2 millimeter wave radar sensor assembly connector.
      Fig 3: Identifying A2 Harness Connector Terminals
      GTY409589Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Millimeter Wave Radar Sensor Assembly)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A2-4 (CA1P) - A2-3 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

    NG → REPAIR OR REPLACE CAN MAIN BUS LINE (DRIVING SUPPORT ECU ASSEMBLY - MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 

    OK → See step   8 

  5. CHECK FOR OPEN IN SENSOR BUS MAIN LINE (DRIVING SUPPORT ECU ASSEMBLY) 
    1. Disconnect the H5 driving support ECU assembly connector.
    2. Measure the resistance according to the value(s) in the table below.
      Fig 4: Identifying H5 Harness Connector Terminals
      GTY417637Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition Purpose
      H5-40 (CA1P) - H5-25 (GND) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω:
      CANH ground short
      H5-18 (CA1N) - H5-25 (GND) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω:
      CANL ground short
      H5-40 (CA1P) - H5-30 (B) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ:
      CANH +B short
      H5-18 (CA1N) - H5-30 (B) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ:
      CANL +B short
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Driving Support ECU Assembly)

      HINT: 

      It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sensor Bus Lines inspection.

      Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sensor Bus Lines inspection.

    NG → See step   6 

    OK → See step   7 

  6. CHECK FOR SHORT IN SENSOR BUS MAIN LINE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 
    1. Disconnect the A2 millimeter wave radar sensor assembly connector.
    2. Measure the resistance according to the value(s) in the table below.
      Fig 5: Identifying H44 DLC Terminals And A2 Harness Connector Terminals
      GTY401640Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition Purpose
      A2-4 (CA1P) - H44-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω:
      CANH ground short
      A2-3 (CA1N) - H44-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω:
      CANL ground short
      A2-4 (CA1P) - H44-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ:
      CANH +B short
      A2-3 (CA1N) - H44-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ:
      CANL +B short
      TEXT IN ILLUSTRATION

      *1 DLC3
      *a Front view of wire harness connector
      (to Millimeter Wave Radar Sensor Assembly)

      HINT: 

      It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sensor Bus Lines inspection.

      Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sensor Bus Lines inspection.

    NG → REPAIR OR REPLACE CAN MAIN BUS LINE (DRIVING SUPPORT ECU ASSEMBLY - MILLIMETER WAVE RADAR SENSOR ASSEMBLY) 

    OK → See step   8 

  7. REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  REMOVAL [08/2012 - ] 
  8. REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY. Refer to  REMOVAL [08/2012 - ] 
scientia non olet · About LEMON Manuals