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Home >> Lexus >> 2017 >> RC 350 Base, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Meter / Gauge System - Symptom Tests (2 Of 2) & Circuit Tests >> Meter / Gauge System >> Speed Signal Circuit [11/2017 - 11/2019] >> Procedure

Speed Signal Circuit [11/2017 - 11/2019]: Procedure

  1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE) 
    1. Disconnect the O3 combination meter assembly connector.
      GTY504262Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      HINT: 

      If any of the ECUs specified in the wiring diagram supplies power to the combination meter assembly, the combination meter assembly will output a waveform.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  2

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) 
    1. Connect the O3 combination meter assembly connector.
    2. Disconnect the A89 brake actuator assembly (skid control ECU) connector.
      GTY794944Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Brake Actuator Assembly (Skid Control ECU))
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A89-14 (SP1) - Body ground Engine switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  4

    Result: 

    OK 

    See step  3

  3. INSPECT BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) (INPUT WAVEFORM) 
    1. Check the input waveform.
      GTY512715Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Combination Meter Assembly)
      1. Connect the A89 brake actuator assembly (skid control ECU) connector.
      2. Remove the combination meter assembly with the connector(s) still connected.
      3. Connect an oscilloscope to terminal O3-20 (SI) and body ground.
      4. Turn the engine switch on (IG).
      5. Turn a wheel slowly.
      6. Check the signal waveform according to the condition(s) in the table below.
        Item Condition
        Tool setting 5 V/DIV., 20 ms./DIV.
        Vehicle condition Engine switch on (IG), wheel being rotated

        OK

        The waveform is similar to that shown in the illustration.

        HINT: 

        When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU). Refer to  REMOVAL [11/2017 - 11/2021] 

  4. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU)) 
    1. Disconnect the O3 combination meter assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      O3-20 (SI) - A89-14 (SP1) Always Below 1 Ω
      O3-20 (SI) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  5. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - EACH ECU) 
    1. Disconnect the A82*4 or A91*5 ECM connector.
    2. Disconnect the O6 certification ECU (smart key ECU assembly) connector.
    3. Disconnect the O143 radio receiver assembly connector.
    4. Disconnect the O147 navigation ECU connector*1.
    5. Disconnect the O65 DCM (telematics transceiver) connector*3.
    6. Disconnect the T20*1 or T38*2 stereo component amplifier assembly connector.
      1. *1: w/ Navigation System
      2. *2: w/o Navigation System
      3. *3: w/ Manual (SOS) Switch
      4. *4: for 8AR-FTS
      5. *5: for 2GR-FKS
    7. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. INSPECT ECM (SHORT CIRCUIT IN ECM) 
    1. Connect the O6 certification ECU (smart key ECU assembly) connector.
    2. Connect the O143 radio receiver assembly connector.
    3. Connect the O147 navigation ECU connector*1.
    4. Connect the O65 DCM (telematics transceiver) connector*3.
    5. Connect the T20*1 or T38*2 stereo component amplifier assembly connector.
      1. *1: w/ Navigation System
      2. *2: w/o Navigation System
      3. *3: w/ Manual (SOS) Switch
    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the ECM.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM 

    for 2GR-FKS: Refer to REMOVAL [11/2017 - ]

    for 8AR-FTS: Refer to REMOVAL [10/2015 - ]

    Result: 

    NG 

    See step  7

  7. INSPECT RADIO RECEIVER ASSEMBLY (SHORT CIRCUIT IN RADIO RECEIVER ASSEMBLY) 
    1. Connect the A82*1 or A91*2 ECM connector.
      1. *1: for 8AR-FTS
      2. *2: for 2GR-FKS
    2. Disconnect the O143 radio receiver assembly connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the radio receiver assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE RADIO RECEIVER ASSEMBLY. Refer to  REMOVAL [11/2017 - 10/2018]  , or refer to  REMOVAL [10/2018 - ] 

    Result: 

    NG 

    See step  8

  8. CONFIRM MODEL 
    1. Choose the model to be inspected.

      Result

      Result Proceed to
      w/ Navigation System A
      w/o Navigation System B

    Result: 

    B 

    See step  12

    Result: 

    A 

    See step  9

  9. INSPECT NAVIGATION ECU (SHORT CIRCUIT IN NAVIGATION ECU) 
    1. Connect the O143 radio receiver assembly connector.
    2. Disconnect the O147 navigation ECU connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the radio receiver assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NAVIGATION ECU. Refer to  REMOVAL [11/2017 - ] 

    Result: 

    NG 

    See step  10

  10. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY) 
    1. Connect the O147 navigation ECU connector.
    2. Disconnect the T20 stereo component amplifier assembly connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result

      Result Proceed to
      OK A
      NG (w/o Manual (SOS) Switch) B
      NG (w/ Manual (SOS) Switch) C

    Result: 

    A 

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    B 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    C 

    See step  11

  11. INSPECT DCM (TELEMATICS TRANSCEIVER) (SHORT CIRCUIT IN DCM (TELEMATICS TRANSCEIVER)) 
    1. Connect the T20 stereo component amplifier assembly connector.
    2. Disconnect the O65 DCM (telematics transceiver) connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the DCM (telematics transceiver).

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE DCM (TELEMATICS TRANSCEIVER). Refer to  REMOVAL [11/2017 - 11/2019] 

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [09/2014 - ] 

  12. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (SHORT CIRCUIT IN STEREO COMPONENT AMPLIFIER ASSEMBLY) 
    1. Connect the O143 radio receiver assembly connector.
    2. Disconnect the T21 stereo component amplifier assembly connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the stereo component amplifier assembly.

      Result

      Result Proceed to
      OK A
      NG (w/o Manual (SOS) Switch) B
      NG (w/ Manual (SOS) Switch) C

    Result: 

    A 

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    B 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    C 

    See step  13

  13. INSPECT DCM (TELEMATICS TRANSCEIVER) (SHORT CIRCUIT IN DCM (TELEMATICS TRANSCEIVER)) 
    1. Connect the T21 stereo component amplifier assembly connector.
    2. Disconnect the O65 DCM (telematics transceiver) connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      O3-19 (+S) - Body ground Engine switch on (IG) 4.5 to 14 V

      HINT: 

      If the result is as specified, there may be a short circuit in the DCM (telematics transceiver).

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE DCM (TELEMATICS TRANSCEIVER). Refer to  REMOVAL [11/2017 - 11/2019] 

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [09/2014 - ] 

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