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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Electrical >> Gauges >> Meter / Gauge System (Except 12.3 Inch Display) - Symptom Tests (2 Of 2) & Circuit Tests >> METER / GAUGE SYSTEM (except 12.3 Inch Display) >> Speed Signal Circuit [12/2019 - 10/2022] >> Procedure

Speed Signal Circuit [12/2019 - 10/2022]: Procedure

  1. INSPECT COMBINATION METER ASSEMBLY (INPUT WAVEFORM) 
    GTY840625Courtesy 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 H21-5 (SI) - Body ground
      Tool setting 5 V/DIV., 20 ms./DIV.
      Condition Ignition switch ON, 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  11

    Result: 

    A 

    See step  2

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) 
    GTY910048Courtesy 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 H21-6 (+S) - Body ground
      Tool setting 5 V/DIV., 20 ms./DIV.
      Condition Ignition switch ON, 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 [12/2019 - ] 

    Result: 

    A 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) 
    1. Disconnect the A28 ECM connector.*1
    2. Disconnect the H48 certification ECU (smart key ECU assembly) connector.
    3. Disconnect the H1 radio and display receiver assembly connector.*2
    4. Disconnect the H4 radio receiver assembly connector.*3
    5. Disconnect the H18 navigation ECU connector.*4
    6. Disconnect the M37*3 or M38*2 stereo component amplifier assembly connector.*5
    7. Disconnect the H21 combination meter assembly connector.
    8. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A28-39 (SPD) - H21-6 (+S)*1 Always Below 1 Ω
      H48-19 (SPD) - H21-6 (+S) Always Below 1 Ω
      H1-27 (SPD) - H21-6 (+S)*2 Always Below 1 Ω
      H4-27 (SPD) - H21-6 (+S)*3 Always Below 1 Ω
      H18-9 (SPD) - H21-6 (+S)*4 Always Below 1 Ω
      M37-17 (SPD) - H21-6 (+S)*3, *5 Always Below 1 Ω
      M38-11 (SPD) - H21-6 (+S)*2, *5 Always Below 1 Ω
      1. *1: for Gasoline Model
      2. *2: for 8 Inch Multi-display Type
      3. *3: for 12.3 Inch Multi-display Type
      4. *4: w/ Navigation System
      5. *5: for 11 Speakers

      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) 
    GTY883832Courtesy 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
      A28*1 ECM
      H48 Certification ECU (smart key ECU assembly)
      H1*2 Radio and display receiver assembly
      H4*3 Radio receiver assembly
      H18*4 Navigation ECU
      M37*3, *5 Stereo component amplifier assembly
      M38*2, *5
      1. *1: for Gasoline Model
      2. *2: for 8 Inch Multi-display Type
      3. *3: for 12.3 Inch Multi-display Type
      4. *4: w/ Navigation System
      5. *5: for 11 Speakers
    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
      H21-6(+S) - Body ground Ignition switch ON 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 ECM, the voltage changed to the specified voltage
      (For Gasoline Model)      		 B
      When disconnecting the connector of the certification ECU (smart key ECU assembly), the voltage changed to the specified voltage C
      When disconnecting the connector of the radio and display receiver assembly, the voltage changed to the specified voltage
      (For 8 Inch Multi-display Type)      		 D
      When disconnecting the connector of the radio receiver assembly, the voltage changed to the specified voltage
      (For 12.3 Inch Multi-display Type)      		 E
      When disconnecting the connector of the navigation ECU, the voltage changed to the specified voltage
      (w/ Navigation System)      		 F
      When disconnecting the connector of the stereo component amplifier assembly, the voltage changed to the specified voltage
      (For 11 Speakers)      		 G

    Result: 

    B 

    REPLACE ECM. Refer to  REMOVAL [12/2019 - 09/2020]  , or refer to  REMOVAL [09/2020 - 10/2022] 

    Result: 

    C 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023] 

    Result: 

    D 

    REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    E 

    REPLACE RADIO RECEIVER ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    F 

    REPLACE NAVIGATION ECU. Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    G 

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

    Result: 

    A 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) 
    1. Disconnect the A28 ECM connector.*1
    2. Disconnect the H48 certification ECU (smart key ECU assembly) connector.
    3. Disconnect the H1 radio and display receiver assembly connector.*2
    4. Disconnect the H4 radio receiver assembly connector.*3
    5. Disconnect the H18 navigation ECU connector.*4
    6. Disconnect the M37*3 or M38*2 stereo component amplifier assembly connector.*5
    7. Disconnect the H21 combination meter assembly connector.
    8. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A28-39 (SPD)*1, H48-19 (SPD), H1-27 (SPD)*2, H4-27 (SPD)*3, H18-9 (SPD)*4, M37-17 (SPD)*3, *5 or M38-11 (SPD)*2, *5 - H21-6 (+S) Always Below 1 Ω
      A28-39 (SPD)*1, H48-19 (SPD), H1-27 (SPD)*2, H4-27 (SPD)*3, H18-9 (SPD)*4, M37-17 (SPD)*3, *5, M38-11 (SPD)*2, *5 or H21-6 (+S) - Body ground Always 10 kΩ or higher
      1. *1: for Gasoline Model
      2. *2: for 8 Inch Multi-display Type
      3. *3: for 12.3 Inch Multi-display Type
      4. *4: w/ Navigation System
      5. *5: for 11 Speakers

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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

      Result

      Result Proceed to
      For HV Model A
      For Gasoline Model B

    Result: 

    B 

    See step  9

    Result: 

    A 

    See step  7

  7. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) 
    GTY901681Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to No. 2 Skid Control ECU (Brake Actuator Assembly))
    1. Disconnect the A57 No. 2 skid control ECU (brake actuator assembly) connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A57-18 (SP1) - Body ground Ignition switch ON 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY). Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    NG 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the H21 combination meter assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A57-18 (SP1) or H21-5 (SI) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  9. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) 
    GTY901680Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Skid Control ECU (Brake Actuator Assembly))
    1. Disconnect the A39 skid control ECU (brake actuator assembly) connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A39-18 (SP1) - Body ground Ignition switch ON 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY). Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    NG 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the H21 combination meter assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A39-18 (SP1) or H21-5 (SI) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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

      Result

      Result Proceed to
      For HV Model A
      For Gasoline Model B

    Result: 

    B 

    See step  13

    Result: 

    A 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the A57 No. 2 skid control ECU (brake actuator assembly) connector.
    2. Disconnect the H21 combination meter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A57-18 (SP1) - H21-5 (SI) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY). Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  13. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the A39 skid control ECU (brake actuator assembly) connector.
    2. Disconnect the H21 combination meter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A39-18 (SP1) - H21-5 (SI) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY). Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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