METER / GAUGE SYSTEM Tachometer Malfunction

DESCRIPTION

In this circuit, the combination meter assembly receives engine speed signals from the ECM. The meter CPU displays the engine speed, which is calculated based on the data received from the ECM.

WIRING DIAGRAM

A01J4V6E11

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK COMBINATION METER ASSEMBLY

    A01J5CDE02
    Text in Illustration
    *a

    Front view of wire harness connector

    (to Combination Meter Assembly)

    1. Disconnect the C27 combination meter assembly connector.

    2. Using an oscilloscope, check the signal waveform of the meter.

      Item Condition
      Tester connection C27-7 (S) - Body ground
      Tool setting 5 V/DIV., 10 msec./DIV.
      Condition Engine idling
      OK
      The waveform displayed is as shown in the illustration.

      Tech Tips

      As the engine speed increases, the wavelength shortens.


    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM) Click here

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

  2. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)


    1. Disconnect the C27 combination meter assembly connector.

    2. Disconnect the E9*1 or E13*2 ECM connector.


      • *1: for 2TR-FE

      • *2: for 1GR-FE

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

      Standard Resistance
      for 2TR-FE
      Tester Connection Condition Specified Condition
      C27-7 (S) - E9-1 (TACH) Always Below 1 Ω
      C27-7 or E9-1 (TACH) - Body ground Always 10 kΩ or higher
      for 1GR-FE
      Tester Connection Condition Specified Condition
      C27-7 (S) - E13-1 (TACH) Always Below 1 Ω
      C27-7 (S) or E13-1 (TACH) - Body ground Always 10 kΩ or higher
      Result
      Result Proceed to
      NG A
      OK (for 2TR-FE) B
      OK (for 1GR-FE) C

    B

    GO TO SFI SYSTEM Click here

    C

    GO TO SFI SYSTEM Click here

    A

    REPAIR OR REPLACE HARNESS OR CONNECTOR