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Home >> Lexus >> 2021 >> ES 250 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 172 (Meter / Gauge System (Hybrid) - Diagnostic Codes (2 Of 2) & Symptom Tests) >> METER / GAUGE SYSTEM (for HV Model) >> Speed Signal Circuit [06/2018 - 09/2022] >> Procedure

Speed Signal Circuit [06/2018 - 09/2022]: Procedure

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Lexus ES 300h, 2023 Lexus ES 300h, 2022 Lexus ES 300h, 2021 Lexus ES 300h, and 2020 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.
  1. INSPECT COMBINATION METER ASSEMBLY (INPUT WAVEFORM) 
    GTY797404Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Component with harness connected
    (Combination Meter Assembly)
    *b Waveform
    1. Check the signal waveform according to the condition(s) in the table below.
      Item Condition
      Tester connection G17-20 (SI) - Body ground
      Tool setting 5 V/DIV., 20 ms./DIV.
      Condition Power switch on (IG), wheel being rotated

      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

      Result  Proceed to
      The measured waveform is similar to that in the illustration A
      The measured waveform is not similar to that in the illustration
      (Stuck low)      		 B
      The measured waveform is not similar to that in the illustration
      (Stuck high)      		 C

    Result: 

    B 

    See step  6

    Result: 

    C 

    See step  8

    Result: 

    A 

    See step  2

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) 
    GTY961972Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Component with harness connected
    (Combination Meter Assembly)
    *b Waveform
    1. Check the signal waveform according to the condition(s) in the table below.
      Item Condition
      Tester connection G17-19 (+S) - Body ground
      Tool setting 5 V/DIV., 20 ms./DIV.
      Condition Power switch on (IG), wheel being rotated

      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.
      • The waveform (B) changes depending on the connected ECUs.

      Result

      Result  Proceed to
      The measured waveform is similar to that in the illustration A
      The measured waveform is not similar to that in the illustration
      (Stuck low)      		 B
      The measured waveform is not similar to that in the illustration
      (Stuck high)      		 C

    Result: 

    B 

    See step  4

    Result: 

    C 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - ] 

    Result: 

    A 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) 
    1. Disconnect the G47 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the A54 parking brake ECU (brake actuator assembly) connector.
    3. Disconnect the G9*2 orG11*1 stereo component amplifier assembly connector.
    4. Disconnect the G14 navigation ECU*1 connector.
    5. Disconnect the G5*1 or G6*2 radio receiver assembly connector.
    6. Disconnect the G17 combination meter assembly connector.
    7. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G47-19 (SPD) - G17-19 (+S) Always Below 1 Ω
      A54-27 (SPD) - G17-19 (+S) Always Below 1 Ω
      G9-11 (SPD)*2 - G17-19 (+S) Always Below 1 Ω
      G11-17 (SPD)*1 - G17-19 (+S) Always Below 1 Ω
      G14-9 (SPD)*3 - G17-19 (+S) Always Below 1 Ω
      G5-27 (SPD)*1 - G17-19 (+S) Always Below 1 Ω
      G6-27 (SPD)*2 - G17-19 (+S) Always Below 1 Ω
      1. *1: for 12.3 Inch Display
      2. *2: for 8 Inch Display
      3. *3: w/ Navigation System

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK THE VOLTAGE AT TERMINAL SPD OF EACH ECU 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  4. INSPECT EACH ECU (INTERNAL SHORT) 
    GTY961782Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Component with harness connected
    (Combination Meter Assembly)
    1. Disconnect one of the connectors below.
      NOTE:

      After disconnecting a connector, perform all steps with all other ECUs connected.

      Terminal No. (Symbol) ECU
      A54 Parking brake ECU (brake actuator assembly)
      G47 Certification ECU (smart key ECU assembly)
      G9*2 Stereo component amplifier assembly
      G11*1
      G14*3 Navigation ECU
      G5*1 Radio receiver assembly
      G6*2
      1. *1: for 12.3 Inch Display
      2. *2: for 8 Inch Display
      3. *3: w/ Navigation System
    2. Measure the voltage according to the value(s) in the table below.
      NOTE:

      Make sure to perform this inspection with the wheels stopped.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G17-19 (+S) - Body ground Power switch on (IG) 4.5 to 14 V
    3. Repeat steps (a) and (b) for each connected ECU.

      HINT: 

      If the voltage changed to the specified voltage after disconnecting a connector, an internal short in the disconnected ECU is suspected.

      Result

      Result  Proceed to
      After performing the inspection procedure for all connectors, the voltage did not change to the specified voltage A
      When disconnecting the connector of the certification ECU (smart key ECU assembly), the voltage changed to the specified voltage B
      When disconnecting the connector of the parking brake ECU (brake actuator assembly), the voltage changed to the specified voltage C
      When disconnecting the connector of the stereo component amplifier assembly, the voltage changed to the specified voltage D
      When disconnecting the connector of the navigation ECU, the voltage changed to the specified voltage
      (w/ Navigation System)      		 E
      When disconnecting the connector of the radio receiver assembly, the voltage changed to the specified voltage F

    Result: 

    B 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

    Result: 

    C 

    REPLACE PARKING BRAKE ECU (BRAKE ACTUATOR ASSEMBLY). Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

    Result: 

    D 

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to  REMOVAL [06/2018 - 09/2022] 

    Result: 

    E 

    REPLACE NAVIGATION ECU. Refer to  REMOVAL [06/2018 - 08/2020]  , or refer to  REMOVAL [08/2020 - 09/2022] 

    Result: 

    F 

    REPLACE RADIO RECEIVER ASSEMBLY. Refer to  REMOVAL [06/2018 - 08/2020]  , or refer to  REMOVAL [08/2020 - 09/2022] 

    Result: 

    A 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) 
    1. Disconnect the G47 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the A54 parking brake ECU (brake actuator assembly) connector.
    3. Disconnect the G9*2 or G11*1 stereo component amplifier assembly connector.
    4. Disconnect the G14 navigation ECU*3 connector.
    5. Disconnect the G5*1 or G6*2 radio receiver assembly connector.
    6. Disconnect the G17 combination meter assembly connector.
    7. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G47-19 (SPD), A54-27 (SPD), G9-11 (SPD)*2, G11-17 (SPD)*1, G14-9 (SPD)*3, G5-27 (SPD)*1 or G6-27 (SPD)*2 - G17-19 (+S) Always Below 1 Ω
      G47-19 (SPD), A54-27 (SPD), G9-11 (SPD)*2, G11-17 (SPD)*1, G14-9 (SPD)*3, G5-27 (SPD)*1, G6-27 (SPD)*2 or G17-19 (+S) - Body ground Always 10 kΩ or higher
      1. *1: for 12.3 Inch Display
      2. *2: for 8 Inch Display
      3. *3: w/ Navigation System

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  6. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) 
    GTY812865Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))
    1. Disconnect the A45 skid control ECU (brake booster with master cylinder assembly) connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A45-11 (SP1) - Body ground Power switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY). Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

    Result: 

    NG 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the G17 combination meter assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A45-11 (SP1) or G17-20 (SI) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  8. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the A45 skid control ECU (brake booster with master cylinder assembly) connector.
    2. Disconnect the G17 combination meter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A45-11 (SP1) - G17-20 (SI) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY). Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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