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Home >> Lexus >> 2012 >> IS 250 Base, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Meter & Gauge System (Diagnostics & Symptom Tests) >> Meter / Gauge System >> Symptom Tests >> Speedometer Malfunction >> Procedure

Speedometer Malfunction: Procedure

  1. PERFORM ACTIVE TEST USING TECHSTREAM (SPEED METER OPERATION) 
    1. Connect Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the tester ON.
    4. Enter the following menus: Body Electrical / 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) There is a deviation in the values displayed on the speedometer (*1)
      (Control range → Speedometer display)
      • 0 → 0
      • 40 → 40.0 to 43.5
      • 80 → 80.0 to 84.5
      • 120 → 120.0 to 125.5
      0, 40, 80, 120, 160, 200, 240 km/h (*2) There is a deviation in the values displayed on the speedometer (*2)
      (Control range → Speedometer display)
      • 0 → 0
      • 40 → 38.0 to 42.0
      • 80 → 78.0 to 84.0
      • 120 → 119.0 to 125.0
      • 160 → 159.0 to 167.0
      • 200 → 199.0 to 209.0
      • 240 → 239.0 to 251.0

      *1: for U.S.A.

      *2: except U.S.A.

      OK

      Needle indication is normal.

    NG → REPLACE COMBINATION METER ASSEMBLY 

    OK: Go to next step 

  2. CHECK BRAKE CONTROL SYSTEM 
    1. Check if brake control system DTC is output.

      Result

      Result Proceed to
      Brake control system DTC is not output. A
      Brake control system DTC is output. B

    B → GO TO BRAKE CONTROL SYSTEM 

    A: Go to next step 

  3. READ VALUE USING TECHSTREAM (VEHICLE SPEED METER, FL/FR/RL/RR WHEEL SPEED) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus:
      1. for Combination Meter: Body Electrical / Combination Meter / Data List.
      2. for ABS/VSC/TRAC: Chassis / ABS/VSC/TRAC / 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) -
      ABS/VSC/TRAC

      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

      When the Data List values of the ECUs match, an internal malfunction of the combination meter assembly is suspected.

      NG

      When the Data List values of the ECUs do not match, a signal output error of the skid control ECU or an internal malfunction of the combination meter assembly is suspected.

    NG → See step   4 

    OK → REPLACE COMBINATION METER ASSEMBLY 

  4. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE) 
    1. Disconnect the A58 connector.
      Fig 1: Identifying A58 Connector Terminals
      GTY129370Courtesy 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
      A58-11 (SP1) -
      Body ground      		 Engine switch on (IG) 10 to 14 V

    NG → See step   6 

    OK: Go to next step 

  5. INSPECT SKID CONTROL ECU (INPUT WAVEFORM) 
    1. Check the input signal waveform.
      Fig 2: Identifying Terminals J34--17 (SI) And Body Ground
      GTY135096Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Reconnect the A58 connector.
      2. Remove the combination meter assembly with connector(s) still connected.
      3. Connect the oscilloscope to the terminals J34-17 (SI) and body ground.
      4. Engine 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)

        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 → REPLACE SKID CONTROL ECU 

    OK → REPLACE COMBINATION METER ASSEMBLY 

  6. CHECK HARNESS AND CONNECTOR (COMBINATION METER - SKID CONTROL ECU) 
    1. Disconnect the A58 and J34 connectors.
      Fig 3: Identifying A58 And J34 Connectors
      GTY140753Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      A58-11 (SP1) - J34-17 (SI) Always Below 1 Ω
      A58-11 (SP1) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → REPLACE COMBINATION METER ASSEMBLY 

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