Inspection Procedure

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

   OK: The meter operations normally. 

1. NG: CHECK AND REPLACE COMBINATION METER ASSY 
2. OK: GO TO NEXT STEP 

1. Check output value of tachometer.
   1. Connect the OBD II scan tool or LEXUS hand-held tester to DLC3.
   2. Turn the ignition switch ON and push the OBD II scan tool or LEXUS hand-held tester main switch ON.
   3. Select the DATA LIST mode on the OBD II scan tool or LEXUS hand-held tester.
   4. When driving the vehicle, check that parameter of tachometer change on the screen of the OBD II scan tool or LEXUS 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 

(REFERENCE) INSPECTION USING OSCILLOSCOPE 

1. Check the output wave.
   1. Remove the ECM with connectors still connected.
   2. Connect the oscilloscope to the terminals TACH and E1 of ECM.
   3. Start engine.
   4. Check the signal waveform.
   SIGNAL WAVEFORM CHART
   
   

   Item	Contents
   Tool setting	10 V / DIV, 20 ms / DV
   Vehicle condition	Engine idle speed

   Fig 1: Connecting Oscilloscope To Terminals TACH & E1 Of ECM

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. NG: CHECK AND REPLACE ECM 
2. OK: GO TO NEXT STEP. 

Fig 2: Checking Signal Waveform

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

(REFERENCE) INSPECTION USING OSCILLOSCOPE 

1. Check the output wave.
   1. Remove the combination meter with connectors still connected.
   2. Connect the oscilloscope to the terminal S of combination meter and body ground.
   3. Start engine.
   4. Check the signal waveform.
   SIGNAL WAVEFORM CHART
   
   

   Item	Contents
   Tool setting	10 V / DIV, 20 ms / DV
   Vehicle condition	Engine idle speed

   Fig 3: Connecting Oscilloscope To Terminals Of Combination Meter & Body Ground

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 
2. OK: CHECK COMBINATION METER ASSY 

Fig 4: Checking Signal Waveform

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002