Inspection Procedure

1. Check tachometer operation.
   1. Connect the OBD II scan tool or TOYOTA hand-held tester to DLC3.
   2. Turn the ignition switch ON and push the OBD II scan tool or TOYOTA hand-held tester main switch ON.
   3. Select the ACTIVE TEST mode on the OBD II scan tool or TOYOTA hand-held tester.
   4. Check that the prove moves as OBD II scan tool or TOYOTA hand-held tester directs in each range.
   1. OK: The Meter Operations Normally. Go To Next Step  , (Read Value Of OBD II Scan Tool Or Toyota Hand-Held Tester).
   2. NG: Check And Replace Combination Meter Assy 

1. Check output value of ECM.
   1. Connect the OBD II scan tool or TOYOTA hand-held tester to DLC3.
   2. Turn the ignition switch ON and push the OBD II scan tool or TOYOTA hand-held tester main switch ON.
   3. Select the DATA LIST mode on the OBD II scan tool or TOYOTA hand-held tester.
   4. When driving the vehicle, check that parameter of tachometer change on the screen of the OBD II scan tool or TOYOTA hand-held tester.
   1. OK: There Is Almost No Difference From The Displayed Engine RPM Value. Go To Step 3  , (Check ECM (Tacho).
   2. NG: Go To Engine Control System (See  REPAIR INSTRUCTIONS  or  ENGINE CONTROL SYSTEM  ) 

(Reference) Inspection Using Oscilloscope 

1. Check the output wave.
   Fig 1: Reviewing Oscilloscope Output Wave

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   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 2: Reviewing ECM Information

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Fig 3: Identifying ECM Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. OK: Go To Step 4,  (Check Combination Meter Assy (Tacho).
2. NG: Check And Replace ECM 

(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 C12-1 of combination meter and body ground.
      Fig 4: Identifying Combination Meter Terminal C12-1

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 5: Reviewing Combination Meter Information

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. Start engine.
   4. Check the signal waveform.
   Fig 6: Reviewing Oscilloscope Wave Pattern
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. OK: Check And Replace Combination Meter Assy 
2. NG: Repair Or Replace Harness Or Connector