Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter: Procedure

1. Check the output waveform.
   Fig 1: F15 Connector & Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Remove the combination meter assembly with the connector still connected.
   2. Connect an oscilloscope to terminal F15-3 (+S) and body ground.
   3. Turn the engine switch on (IG).
   4. Turn a wheel slowly.
   5. Check the signal waveform according to the condition(s) in the table below.

      Item	Condition
      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
      
      

      *1	Component with harness connected (Combination Meter Assembly)

NG → See step   4 

OK: Go to next step 

1. Disconnect the stereo component amplifier assembly connector and combination meter assembly connector.
   Fig 2: Stereo Component Amplifier Assembly Connector And Combination Meter Assembly Connector

   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
   O15-2 (SPD) - F15-3 (+S)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Stereo Component Amplifier Assembly)
   *2	Front view of wire harness connector (to Combination Meter Assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   3