METER / GAUGE SYSTEM Speedometer Malfunction

DESCRIPTION

The meter CPU receives vehicle speed signals from this circuit. The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU. Skid control ECU supplies power to the vehicle speed sensor. Skid control ECU detects vehicle speed signals based on the pulses of the voltage. Skid control ECU transmits vehicle speed signals as pulses to the meter CPU. The meter CPU calculates the vehicle speed converting 4 pulses to 1 revolution.

Tech Tips

Factors that affect the indicated vehicle speed include tire size, tire inflation, and tire wear. The speed indicated on the speedometer has an allowable margin of error. This can be tested using a speedometer tester (calibrated chassis dynamometer). For details about testing and the margin of error, see the reference chart Click here.

WIRING DIAGRAM

A0161HDE14

INSPECTION PROCEDURE

Note

If the vehicle speed is outside the allowable range when tested, perform the following procedure Click here.

Tech Tips

Before starting circuit inspection, check tire size and tire pressure.

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (SPEED METER OPERATION)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the intelligent tester on.

    4. Enter the following menus: Body / Combination Meter / Active Test.

    5. Check the operation by referring to the table below.

      Combination Meter
      Tester Display Test Part Control Range Diagnostic Note
      Speed Meter Operation Speedometer 0, 40, 80, 120 mph*1 Confirm that the vehicle is stopped, engine idling
      0, 40, 80, 120, 160, 200, 240 km/h*2

      • *1: for RHD

      • *2: for LHD

      OK
      Speedometer indication is normal.

    NG

    REPLACE COMBINATION METER Click here

    OK

  2. READ VALUE USING INTELLIGENT TESTER (VEHICLE SPEED METER)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the intelligent tester on.

    4. Enter the following menus: Body / Combination Meter / Data List.

    5. Check the values by referring to the values in the table below.

      Combination Meter
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Vehicle Speed Meter Vehicle speed/Min.: 0 km/h (0 mph), Max.: 255 km/h (158 mph) Almost same as actual speed (speedometer tester) -
      OK
      Vehicle speed displayed on the intelligent tester is almost the same as the actual vehicle speed measured using a speedometer tester (calibrated chassis dynamometer).

    NG

    READ VALUE USING INTELLIGENT TESTER (FL/FR/RL/RR WHEEL SPEED) Click here

    OK

    REPLACE COMBINATION METER Click here

  3. READ VALUE USING INTELLIGENT TESTER (FL/FR/RL/RR WHEEL SPEED)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the intelligent tester on.

    4. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

    5. Check the values by referring to the table below.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR Wheel Speed Vehicle speed/Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) Almost same as actual speed (speedometer tester) -
      FL Wheel Speed Vehicle speed/Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) Almost same as actual speed (speedometer tester) -
      RR Wheel Speed Vehicle speed/Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) Almost same as actual speed (speedometer tester) -
      RL Wheel Speed Vehicle speed/Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) Almost same as actual speed (speedometer tester) -
      OK
      Vehicle speed displayed on the intelligent tester is almost the same as the actual vehicle speed measured using a speedometer tester (calibrated chassis dynamometer).

    NG

    GO TO BRAKE CONTROL SYSTEM Click here

    OK

  4. INSPECT COMBINATION METER (OUTPUT VOLTAGE)


    1. A015ZO4E11

      Disconnect the A62 connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A62-11 (SP1) - Body ground Engine switch on (IG) 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER - SKID CONTROL ECU) Click here

    OK

  5. INSPECT SKID CONTROL ECU (INPUT WAVEFORM)


    1. A01611LE02

      Check the input signal waveform.


      1. Remove the combination meter with connector(s) still connected.

      2. Reconnect the A62 connector.

      3. Connect the oscilloscope to the terminals J34-17 (SI) and body ground.

      4. Turn the engine switch on (IG).

      5. Turn the drive 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)
        OK
        The waveform is displayed as shown in the illustration.

        Tech Tips

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


    NG

    REPLACE SKID CONTROL ECU Click here

    OK

    REPLACE COMBINATION METER Click here

  6. CHECK HARNESS AND CONNECTOR (COMBINATION METER - SKID CONTROL ECU)


    1. A0161IIE05

      Disconnect the J34 and A62 connectors.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A62-11 (SP1) - J34-17 (SI) Always Below 1 Ω
      A62-11 (SP1) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE COMBINATION METER Click here