Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter [08/2015 - ]: Procedure

1. Check the output waveform.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   1. Remove the combination meter assembly with the connector(s) still connected.
   2. Connect an oscilloscope to terminal I18-3 (+S) and body ground.
   3. Turn the ignition switch to ON.
   4. Turn a wheel slowly.
   5. Check the signal waveform according to the condition(s) in the table below.

      Item	Condition
      Measurement terminal	I18-3 (+S) - Body ground
      Tool setting	5 V/DIV., 20 ms./DIV.
      Vehicle condition	Wheel being rotated

      OK

      The waveform is similar to that shown in the illustration.

      HINT: 

      When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

      TEXT IN ILLUSTRATION
      
      

      *a	Component with harness connected (Combination Meter Assembly)

NG → See step   5 

OK: Go to next step 

1. Check the input waveform.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   1. Remove the stereo component amplifier assembly with the connector(s) still connected.
   2. Connect an oscilloscope to terminal I69-11 (SPD) and body ground.
   3. Turn the ignition switch to ON.
   4. Turn a wheel slowly.
   5. Check the signal waveform according to the condition(s) in the table below.

      Item	Condition
      Measurement terminal	I69-11 (SPD) - Body ground
      Tool setting	5 V/DIV., 20 ms./DIV.
      Vehicle condition	Wheel being rotated

      OK

      The waveform is similar to that shown in the illustration.

      HINT: 

      When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

      TEXT IN ILLUSTRATION
      
      

      *a	Component with harness connected (Stereo Component Amplifier Assembly)

NG → See step   3 

OK → See step   6 

1. Disconnect the I69 stereo component amplifier assembly connector.
2. Disconnect the I124 junction connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   I69-11 (SPD) - I124-19	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the I18 combination meter assembly connector.
2. Disconnect the I124 junction connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   I18-3 (+S) - I124-18	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPLACE JUNCTION CONNECTOR