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Home >> Scion >> 2005 >> tC Standard >> Repair and Diagnosis >> Electrical >> Gauges >> Combination Meter >> Malfunction In Tachometer >> Inspection Procedure

Inspection Procedure

  1. READ VALUE OF HAND-HELD TESTER (ENGINE SPEED SIGNAL) 
    1. Operate the hand-held tester according to the steps on the display and select "DATA LIST".

    ECM: 

    HAND-HELD TESTER VALUE

    Item Measurement Item/ Range (Display) Normal Condition Diagnostic Note
    Engine Speed Engine speed/Min.: 0 rpm. Max.: 16,383 rpm Almost the same as the actual engine speed (When engine is running) -

    OK: 

    1. Engine speed displayed on the tester is almost the same as the actual engine speed. 

    NG: GO TO ENGINE CONTROL SYSTEM (See  HOW TO PROCEED WITH TROUBLESHOOTING  ) 

    OK: Go to next step 

  2. INSPECT COMBINATION METER ASSY 

    INSPECTION USING OSCILLOSCOPE 

    1. Check the input signal wave form.
      1. Remove the combination meter assy with connector still connected.
      2. Connect the oscilloscope to terminal C6-26 and body ground.
      3. Start the engine.
        Fig 1: Connecting Oscilloscope To Terminal C6-26 And Body Grounds
        G03065180Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      4. Check the signal wave form according to the condition(s) shown in SIGNAL WAVE CONDITION(S)  .
    SIGNAL WAVE CONDITION(S)

    Item Condition
    Tool setting 5 V/DIV, 10 ms/DIV
    Vehicle condition Engine idle speed

    OK: 

    1. As shown in  Fig 2 
    Fig 2: Identifying Waveform Graph
    G03065181Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: Go to step 3 

    OK: REPLACE COMBINATION METER ASSY (See  ON-VEHICLE INSPECTION  ) 

  3. CHECK HARNESS AND CONNECTOR (BETWEEN ECM AND COMBINATION METER ASSY) (See  HOW TO PROCEED WITH TROUBLESHOOTING  ) 
    1. Disconnect the C6 and E4 connectors.
    2. Measure the resistance according to the value(s) in the table shown in ECM AND COMBINATION METER ASSY TERMINAL RESISTANCE .

    Standard: 

    ECM AND COMBINATION METER ASSY TERMINAL RESISTANCE

    Tester connection Condition Specified condition
    C6-26 - E4-5 Always Below 1 Ω
    C6-26 - Body ground Always 10 kΩ or higher
    Fig 3: Identifying ECM And Combination Meter Assy Connector
    G03065182Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE ECM