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Home >> Toyota >> 2003 >> Highlander Limited, FWD >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Combination Meter - Diagnostics >> Malfunction In Tachometer >> Inspection Procedure

Inspection Procedure

  1. PERFORM ACTIVE TEST BY OBD II SCAN TOOL OR HAND-HELD TESTER 
    1. Check tachometer operation.
      1. Connect the OBD II scan tool or hand-held tester to DLC3.
      2. Turn the ignition switch ON and push the OBD II scan tool or hand-held tester main switch ON.
      3. Select the ACTIVE TEST mode on the OBD II scan tool or hand-held tester.
      4. Check that the prove moves as OBD II scan tool or hand-held tester directs in each range.

      OK: The tachometer operates normally. 

    1. NG: CHECK AND REPLACE COMBINATION METER ASSEMBLY 
    2. OK: GO TO NEXT STEP 
  2. READ VALUE OF OBD II SCAN TOOL OR HAND-HELD TESTER 
    1. Check output value of ECM.
      1. Connect the OBD II scan tool or hand-held tester to DLC3.
      2. Turn the ignition switch ON and push the OBD II scan tool or hand-held tester main switch ON.
      3. Select the DATA LIST mode on the OBD II scan tool or hand-held tester.
      4. When driving the vehicle, check that parameter of tachometer change on the screen of the OBD II scan tool or hand-held tester.

      OK: There is almost no difference from the displayed engine RPM value. 

    1. NG: GO TO ENGINE CONTROL SYSTEM 
    2. OK: GO TO NEXT STEP 
  3. CHECK ECM (TACHO) 
    1. Remove the ECM with connectors still connected.
    2. Connect the oscilloscope to the terminals TACH (E6-27) and E1 (E8-17) of ECM.
    3. Start the engine.
    4. Check the signal waveform.

      Reference: 

    OSCILLOSCOPE SPECIFICATIONS

    Item Contents
    Tool Setting 10 V/DIV, 20msec/DIV
    Vehicle Condition Engine Idle Speed
    Fig 1: Identifying ECM Connector Terminals
    G02828484Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    Fig 2: Identifying Oscilloscope Waveform Pattern
    G02828485Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: CHECK AND REPLACE ECM 
    2. OK: GO TO NEXT STEP 
  4. CHECK COMBINATION METER ASSEMBLY (TACHO) 
    1. Remove the combination meter with connectors still connected.
    2. Connect the oscilloscope to the terminal C12-1 of combination meter and body ground.
    3. Start the engine.
    4. Check the signal waveform.

      Reference: 

    OSCILLOSCOPE SPECIFICATIONS

    Item Contents
    Tool Setting 10 V/DIV, 20 msec/DIV
    Vehicle Condition Engine Idle Speed
    Fig 3: Identifying Combination Meter Connector Terminals
    G02828486Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    Fig 4: Identifying Oscilloscope Wave Form Pattern
    G02828487Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK: CHECK AND REPLACE COMBINATION METER ASSEMBLY 
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