Tachometer Malfunction: Procedure

1. Check the input signal waveform.
   Fig 1: Identifying C11 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Remove the combination meter assembly with the connector(s) still connected.
   2. Connect the oscilloscope to the terminals C11-13 (TM IN) and body ground.
   3. Start the engine.
   4. Check the signal waveform according to the condition(s) in the table below.
      Fig 2: Identifying Signal Waveform Graph

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Item	Condition
      Tool Setting	5 V/DIV., 20 ms/DIV.
      Vehicle Condition	Engine idle speed

      OK

      The waveform is displayed as shown in the illustration.

NG → See step   2 

OK → REPLACE COMBINATION METER ASSEMBLY 

1. Disconnect the C11 and E8 connectors.
   Fig 3: Identifying C11 & E8 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   TM IN (C11-13) - E8-1(TACH)	Always	Below 1 Ω
   TM IN (C11-13) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPLACE ECM