Inspection Procedure

1. Select the ACTIVE TEST, use the hand-held tester to generate a control command and then check that the tachometer operates.

   Combination meter assy: 

   COMBINATION METER - ACTIVE TEST
   
   

   Item	Test Details	Diagnostic Note
   TACHOMETER	Tachometer operation (rpm) 0/1000/2000/3000/4000/5000/6000/7000	Confirm that vehicle is stopped and engine is idling

OK: The meter operates normally. 

NG: REPLACE COMBINATION METER ASSY (See  COMBINATION METER ASSY  ) 

OK: GO TO NEXT STEP 

1. Check the DATA LIST for proper functioning of the tachometer.

   Combination meter assy: 

   COMBINATION METER - DATA LIST
   
   

   Item	Measurement Item/Display (Range)	Normal Condition	Diagnostic Note
   TACHOMETER	Engine speed/Min.: 0 rpm, Max.: 12,750 rpm	Almost equal to actual engine speed (when engine running)	-

OK: Engine speed on tester is almost equal to the actual engine speed. 

NG: Go to step 3 

OK: REPLACE COMBINATION METER ASSY (See  COMBINATION METER ASSY  ) 

1. Using an oscilloscope, check the signal waveform of the ECM.

   Standard: 

   TESTER CONNECTION VEHICLE CONDITION
   
   

   Tester Connection	Tester Range	Vehicle Condition
   E5-16 (TACH) - E3-7 (E1)	10 V/DIV., 20 msec./DIV.	Engine idling

OK: As shown in the illustration 

Fig 1: Identifying Oscilloscope Signal Waveform

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

• As the engine speed increases, the wavelength shortens.
• Connect the tester's positive (+) lead to TACH terminal and negative (-) lead to E1 terminal.

NG: Go to SFI SYSTEM ( See  SFI SYSTEM - DIAGNOSTICS  ) 

OK: GO TO NEXT STEP 

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

   Standard: 

   TESTER CONNECTION VEHICLE CONDITION
   
   

   Tester Connection	Tester Range	Vehicle Condition
   C8-5 (S) - Body ground	10 V/DIV., 20 msec./DIV.	Engine idling

   Fig 2: Identifying Combination Meter Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: As shown in the illustration 

HINT:

As the vehicle speed increases, the wavelength shortens.

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: REPLACE COMBINATION METER ASSY (See  COMBINATION METER ASSY  )