Inspection Procedure

PERFORM ACTIVE TEST BY LEXUS HAND-HELD TESTER
1. Check tachometer operation.
1. Connect LEXUS hand-held tester to DLC3.
2. Turn the ignition switch ON and push LEXUS hand-held tester main switch ON.
3. Select the ACTIVE TEST mode on LEXUS hand-held tester.
4. Check that the probe moves as 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 STEP 2 .
READ VALUE OF LEXUS HAND-HELD TESTER
1. Check output value of tachometer.
1. Connect LEXUS hand-held tester to DLC3.
2. Turn the ignition switch ON and push LEXUS hand-held tester main switch ON.
3. Select the DATA LIST mode on LEXUS hand-held tester.
4. When driving the vehicle, check that parameter of tachometer change on the screen of 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 STEP 3 .
INSPECT ECM (TACH)
(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.
  
  Fig 1: Oscilloscope And Vehicle Conditions Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: Locating ECM (-) and TACH (+) Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 3: Identifying Oscilloscope Waveform - TACH And E1 Of Terminals ECM
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: CHECK AND REPLACE ECM
2. OK: GO TO STEP 4 .
INSPECT COMBINATION METER ASSY (S)
(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.
  
  Fig 4: Oscilloscope And Vehicle Conditions Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 5: Identifying Terminal S
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 6: Identifying Oscilloscope Waveform - Terminal S Of Combination Meter And Body Ground
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
2. OK: CHECK AND REPLACE COMBINATION METER ASSY