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Home >> Toyota >> 2012 >> Prius Two >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Meter / Gauge System (Except Plug-In) (Diagnostic Codes & Symptom Tests) >> Meter / Gauge System >> Circuit Test >> Speed Signal Circuit >> Procedure

Speed Signal Circuit: Procedure

  1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE) 
    1. Disconnect the L27 connector.
      Fig 1: Identifying L27 ECU Terminal Voltage Connector Terminal
      GTY216640Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      L27-7 (+S) - Body ground Power switch on (IG) 4.5 to 14 V
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Combination Meter Assembly (No. 3 Meter Circuit Plate))

      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.

    NG → See step   5 

    OK: Go to next step 

  2. INSPECT COMBINATION METER ASSEMBLY (NO. 3 METER CIRCUIT PLATE) (OUTPUT VOLTAGE) 
    1. Reconnect the L27 connector.
    2. Disconnect the A58 connector.
      Fig 2: Identifying A58 Connector Terminal
      GTY216649Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A58-11 (SP1) - Body ground Power switch on (IG) 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Skid Control ECU)

    NG → See step   4 

    OK: Go to next step 

  3. INSPECT SKID CONTROL ECU (INPUT WAVEFORM) 
    1. Check the input waveform.
      Fig 3: Identifying L27 Skid Control ECU (Input Waveform)
      GTY223186Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Reconnect the A58 connector.
      2. Remove the combination meter assembly with the connector(s) still connected.
      3. Connect an oscilloscope to terminal L27-8 (SI) and body ground.
      4. Turn the power switch on (IG).
      5. Turn the 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 Driving at approx. 20 km/h (12 mph)
        TEXT IN ILLUSTRATION

        *1 Component with harness connected
        (Combination Meter Assembly)

        OK

        The waveform is displayed as 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.

    NG → See step   19 

    OK → See step   18 

  4. CHECK HARNESS AND CONNECTOR (NO. 3 METER CIRCUIT PLATE - SKID CONTROL ECU) 
    1. Disconnect the L27 and A58 connectors.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A58-11 (SP1) - L27-8 (SI) Always Below 1 Ω
      A58-11 (SP1) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   18 

  5. CHECK HARNESS AND CONNECTOR (NO. 3 METER CIRCUIT PLATE - RADIO AND DISPLAY RECEIVER ASSEMBLY, NAVIGATION ECU SUB-ASSEMBLY) 
    1. Disconnect the L27 and L130*1 or L149*2 connectors.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L130-17 (SPD)*1 - L27-7 (+S) Always Below 1 Ω
      L149-17 (SPD)*2 - L27-7 (+S) Always Below 1 Ω
      L27-7 (+S) - Body ground Always 10 kΩ or higher
      • *1: for Navigation Receiver Type or for Radio and Display Type (w/o Daytime Running Light)
      • *2: for Radio and Display Type (w/ Daytime Running Light)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  6. INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY, NAVIGATION ECU SUB-ASSEMBLY (OUTPUT VOLTAGE) 
    1. Reconnect the L130*1 or L149*2 connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      L130-17 (SPD)*1 - Body ground Power switch on (IG) 4 to 14 V
      L149-17 (SPD)*2 - Body ground Power switch on (IG) 4 to 14 V
      • *1: for Navigation Receiver Type or for Radio and Display Type (w/o Daytime Running Light)
      • *2: for Radio and Display Type (w/ Daytime Running Light)

      Result

      Result Proceed to
      OK A
      NG (for Radio and Display Type (w/ Daytime Running Light)) B
      NG (for Navigation Receiver Type or for Radio and Display Type (w/o Daytime Running Light)) C

    B → See step   20 

    C → REPLACE NAVIGATION ECU SUB-ASSEMBLY 

    A: Go to next step 

  7. INSPECT VEHICLE APPROACHING SPEAKER CONTROLLER ASSEMBLY (OUTPUT VOLTAGE) 
    1. Reconnect the L140 connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      L140-6 (SPD) - Body ground Power switch on (IG) 4 to 14 V

    NG → REPLACE VEHICLE APPROACHING SPEAKER CONTROLLER 

    OK: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - NO. 3 JUNCTION BLOCK) 
    1. Disconnect the 3A connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L27-7 (+S) - 3A-26 Always Below 1 Ω
      L27-7 (+S) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. CHECK HARNESS AND CONNECTOR (NO. 3 JUNCTION BLOCK (INSTRUMENT PANEL WIRE)) 
    1. Inspect for a short in the circuit that is connected to the junction block connector shown in the wiring diagram.

      HINT: 

      If voltage is not present, it is possible that an ECU or circuit has a malfunction. The malfunctioning ECU or circuit will be diagnosed in the following steps.

      1. Disconnect the 3B connector.
        Fig 4: Identifying ECU 3B & 3A Connector Terminals
        GTY225696Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Measure the voltage according to the value(s) in the table below.

        Standard Voltage

        Tester Connection Condition Specified Condition
        3A-2 - Body ground Power switch on (IG) 4.5 to 14 V
        3B-1 - Body ground Power switch on (IG) 4.5 to 14 V
        3B-85 - Body ground Power switch on (IG) 4.5 to 14 V
        TEXT IN ILLUSTRATION

        *1 Front view of wire harness connector
        (to No. 3 Junction Block)

        Result

        Result Proceed to
        Voltage is not present in one circuit. A
        Voltage is present in all the circuits. B

    B → REPLACE NO. 3 JUNCTION BLOCK (INSTRUMENT PANEL WIRE) 

    A: Go to next step 

  10. CHECK HARNESS AND CONNECTOR (NO. 3 JUNCTION BLOCK - NO. 4 JUNCTION BLOCK) 
    1. Disconnect the 4A connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3B-85 - 4A-21 Always Below 1 Ω
      3B-85 - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  11. CHECK HARNESS AND CONNECTOR (NO. 4 JUNCTION BLOCK (INSTRUMENT PANEL WIRE)) 
    1. Inspect for a short in the circuit that is connected to the junction block connector shown in the wiring diagram.

      HINT: 

      If voltage is not present, it is possible that an ECU or circuit has a malfunction. The malfunctioning ECU or circuit will be diagnosed in the following steps.

      1. Measure the voltage according to the value(s) in the table below.
        Fig 5: Identifying Harness And Connector (No. 4 Junction Block (Instrument Panel Wire))
        GTY338352Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Standard Voltage

        Tester Connection Condition Specified Condition
        4A-56 - Body ground Power switch on (IG) 4.5 to 14 V
        4A-69 - Body ground Power switch on (IG) 4.5 to 14 V
        TEXT IN ILLUSTRATION

        *1 Front view of wire harness connector
        (to No. 4 Junction Block)

        Result

        Result Proceed to
        Voltage is not present in one circuit. A
        Voltage is present in all the circuits. B

    B → REPLACE NO. 4 JUNCTION BLOCK (INSTRUMENT PANEL WIRE) 

    A: Go to next step 

  12. SYSTEM CHECK 
    1. Select the circuit for which voltage was not present in step 9 or 11.

      Result

      Tester Connection System that Uses the Circuit Proceed to
      3A-2 - Body ground Smart Key System A
      4A-69 - Body ground Audio/Visual System B
      3B-1*1 - Body ground Tire Pressure Warning ECU C
      4A-56*2 - Body ground Lighting System D
      4A-80*3 - Body ground Safety Connect System E
      • *1: w/ Tire Pressure Warning System
      • *2: w/ Automatic Type Headlight Beam Level Control
      • *3: w/ Manual (SOS) Switch

    B → See step   14 

    C → See step   15 

    D → See step   16 

    E → See step   17 

    A: Go to next step 

  13. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU CIRCUIT) 
    1. Disconnect the L5 connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L5-14 (SPDI) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   21 

  14. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY CIRCUIT) 
    1. Disconnect the L143 connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L143-11 (SPD) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   22 

  15. CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU CIRCUIT) 
    1. Disconnect the L4 connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L4-2 (SPD) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   23 

  16. CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU CIRCUIT) 
    1. Disconnect the A48 connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A48-16 (SPDR) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   24 

  17. CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) CIRCUIT) 
    1. Disconnect the L144 connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L144-10 (SPDP) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   25 

  18. REPLACE COMBINATION METER ASSEMBLY (NO. 3 METER CIRCUIT PLATE). Refer to  DISASSEMBLY 
  19. REPLACE SKID CONTROL ECU. Refer to  REMOVAL 
  20. REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY. Refer to  REMOVAL 
  21. REPLACE POWER MANAGEMENT CONTROL ECU. Refer to  REMOVAL 
  22. REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to  REMOVAL 
  23. REPLACE TIRE PRESSURE WARNING ECU. Refer to  REMOVAL 
  24. REPLACE HEADLIGHT LEVELING ECU ASSEMBLY. Refer to  REMOVAL 
  25. REPLACE DCM (TELEMATICS TRANSCEIVER). Refer to  REMOVAL 
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