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Speed Signal Circuit [01/2019 - 04/2020]: Procedure

WARNING: This page is about a different car, the 2022 Toyota Corolla, 2021 Toyota Corolla, 2020 Toyota Corolla, and 2019 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.
  1. INSPECT COMBINATION METER ASSEMBLY (INPUT WAVEFORM) 
    GTY870211Courtesy 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 I4-20 (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  14

    Result: 

    A 

    See step  2

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) 
    GTY984951Courtesy 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 I4-36 (+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 [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    A 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) 
    1. Disconnect the A47*1 or A46*2 ECM connector.
    2. Disconnect the I68 stereo component amplifier assembly*3 connector.
    3. Disconnect the I55 radio and display receiver assembly connector.
    4. Disconnect the I69 navigation ECU*4 connector.
    5. Disconnect the C80 TCM*5 connector.
    6. Disconnect the I72 DCM (telematics transceiver)*6 connector.
    7. Disconnect the I4 combination meter assembly connector.
    8. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A47-42 (SPD) - I4-36 (+S)*1 Always Below 1 Ω
      A46-44 (SPD) - I4-36 (+S)*2 Always Below 1 Ω
      I68-11 (SPD) - I4-36 (+S)*3 Always Below 1 Ω
      I55-27 (SPD) - I4-36 (+S) Always Below 1 Ω
      I69-9 (SPD) - I4-36 (+S)*4 Always Below 1 Ω
      C80-42 (SPD) - I4-36 (+S)*5 Always Below 1 Ω
      I72-10 (SPDP) - I4-36 (+S)*6 Always Below 1 Ω
      1. *1: for M20A-FKS
      2. *2: for 2ZR-FAE
      3. *3: except 6 Speakers
      4. *4: w/ Navigation System
      5. *5: for CVT and M20A-FKS
      6. *6: w/ Manual (SOS) Switch

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK THE VOLTAGE AT TERMINAL SPD OR SPDP OF EACH ECU 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  4. INSPECT EACH ECU (INTERNAL SHORT) 
    GTY985494Courtesy 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
      A47*1 ECM
      A46*2
      I68*3 Stereo component amplifier assembly
      I55 Radio and display receiver assembly
      I69*4 Navigation ECU
      C80*5 TCM
      I72*6 DCM (telematics transceiver)
      1. *1: for M20A-FKS
      2. *2: for 2ZR-FAE
      3. *3: except 6 Speakers
      4. *4: w/ Navigation System
      5. *5: for CVT and M20A-FKS
      6. *6: w/ Manual (SOS) Switch
    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
      I4-36 (+S) - Body ground Ignition switch ON 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 ECM, the voltage changed to the specified voltage B
      When disconnecting the connector of the stereo component amplifier assembly, the voltage changed to the specified voltage
      (except 6 Speakers)      		 C
      When disconnecting the connector of the radio and display receiver 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 TCM, the voltage changed to the specified voltage
      (for M20A-FKS and CVT)      		 F
      When disconnecting the connector of the DCM (telematics transceiver), the voltage changed to the specified voltage
      (w/ Manual (SOS) Switch)      		 G

    Result: 

    B 

    REPLACE ECM 

    for M20A-FKS: Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    for 2ZR-FAE: Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    C 

    REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    D 

    REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    E 

    REPLACE NAVIGATION ECU 

    Refer to REMOVAL [06/2018 - 03/2019] , or refer to REMOVAL [03/2019 - 11/2022]

    Result: 

    F 

    REPLACE TCM 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    G 

    REPLACE DCM (TELEMATICS TRANSCEIVER) 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    A 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (EACH ECU - COMBINATION METER ASSEMBLY) 
    1. Disconnect the A47*1 or A46*2 ECM connector.
    2. Disconnect the I68 stereo component amplifier assembly*3 connector.
    3. Disconnect the I55 radio and display receiver assembly connector.
    4. Disconnect the I69 navigation ECU*4 connector.
    5. Disconnect the C80 TCM*5 connector.
    6. Disconnect the I72 DCM (telematics transceiver)*6 connector.
    7. Disconnect the I4 combination meter assembly connector.
    8. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A47-42 (SPD)*1, A46-44 (SPD)*2, I68-11 (SPD)*3, I55-27 (SPD), I69-9 (SPD)*4, C80-42 (SPD)*5 or I72-10 (SPDP)*6 - I4-36 (+S) Always Below 1 Ω
      A47-42 (SPD)*1, A46-44 (SPD)*2, I68-11 (SPD)*3, I55-27 (SPD), I69-9 (SPD)*4, C80-42 (SPD)*5, I72-10 (SPDP)*6 or I4-36 (+S) - Body ground Always 10 kΩ or higher
      1. *1: for M20A-FKS
      2. *2: for 2ZR-FAE
      3. *3: except 6 Speakers
      4. *4: w/ Navigation System
      5. *5: for CVT and M20A-FKS
      6. *6: w/ Manual (SOS) Switch

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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

      Result

      Result Proceed to
      w/ Electric Parking Brake System and Smart Key System A
      w/ Electric Parking Brake System without Smart Key System B
      w/o Electric Parking Brake System and Smart Key System C

    Result: 

    B 

    See step  10

    Result: 

    C 

    See step  12

    Result: 

    A 

    See step  7

  7. CHECK FOR DTC (SMART KEY SYSTEM (FOR START FUNCTION)) 
    1. Check for smart key system (for start function) DTCs are output.

      Body Electrical > Power Source Control > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTCs are output B

    Result: 

    B 

    GO TO SMART KEY SYSTEM (FOR START FUNCTION) 

    Refer to DIAGNOSTIC TROUBLE CODE CHART [01/2019 - 04/2020]

    Result: 

    A 

    See step  8

  8. INSPECT COMBINATION METER ASSEMBLY 

    HINT: 

    This procedure is performed to check the diode inside the combination meter assembly.

    1. Remove the combination meter assembly.

      Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    2. Measure the internal resistance of the combination meter assembly.

      Standard Resistance

      Tester Connection Tester Connection Condition Measured Value
      I4-38 (IG+) - I4-20 (SI)
      • Positive (+) tester probe → I4-38 (IG+)
      • Negative (-) tester probe → I4-20 (SI)
      		 Always A
      I4-38 (IG+) - I4-20 (SI)
      • Positive (+) tester probe → I4-20 (SI)
      • Negative (-) tester probe → I4-38 (IG+)
      		 Always B

      OK

      There is a large difference between the measured value (A) and the measured value (B).

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE COMBINATION METER ASSEMBLY 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the I1 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the I4 combination meter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      I1-21 (SPDO) or I4-20 (SI) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  10. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) 
    GTY935545Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Skid Control ECU (Brake Actuator Assembly))
    1. Disconnect the A51 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
      A51-34 (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 [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    NG 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the I4 combination meter assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A51-34 (SP1) or I4-20 (SI) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  12. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) 
    GTY861133Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Skid Control ECU (Brake Actuator Assembly))
    1. Disconnect the A100 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
      A100-2 (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 [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    NG 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the I4 combination meter assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A100-2 (SP1) or I4-20 (SI) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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

      Result

      Result Proceed to
      w/ Electric Parking Brake System and Smart Key System A
      w/ Electric Parking Brake System without Smart Key System B
      w/o Electric Parking Brake System and Smart Key System C

    Result: 

    B 

    See step  17

    Result: 

    C 

    See step  18

    Result: 

    A 

    See step  15

  15. CHECK FOR DTC (SMART KEY SYSTEM (FOR START FUNCTION)) 
    1. Check for smart key system (for start function) DTCs are output.

      Body Electrical > Power Source Control > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTCs are output B

    Result: 

    B 

    GO TO SMART KEY SYSTEM (FOR START FUNCTION) 

    Refer to DIAGNOSTIC TROUBLE CODE CHART [01/2019 - 04/2020]

    Result: 

    A 

    See step  16

  16. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the I1 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the I4 combination meter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      I1-21 (SPDO) - I4-20 (SI) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  17. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the A51 skid control ECU (brake actuator assembly) connector.
    2. Disconnect the I4 combination meter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A51-34 (SP1) - I4-20 (SI) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  18. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) - COMBINATION METER ASSEMBLY) 
    1. Disconnect the A100 skid control ECU (brake actuator assembly) connector.
    2. Disconnect the I4 combination meter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A100-2 (SP1) - I4-20 (SI) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) 

    Refer to REMOVAL [01/2019 - 03/2019] , or refer to REMOVAL [03/2019 - 09/2022]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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