Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter [10/2014 - 09/2017]: Procedure

1. Check the output waveform.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Combination Meter Assembly)

   1. Remove the combination meter assembly with the connector still connected.
   2. Connect an oscilloscope to terminal I10-19 (+S) and body ground.
   3. Turn the power switch on (IG).
   4. Turn a wheel slowly.
   5. Check the signal waveform according to the condition(s) in the table below.

      Item	Condition
      Measurement terminal	I10-19 (+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.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

GO TO METER / GAUGE SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - ] 

Result: 

OK 

See step  2

1. Disconnect the I38 radio receiver assembly connector.
2. Disconnect the I10 combination meter assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   I38-56 (SPD) - I10-19 (+S)	Always	Below 1 Ω
   I38-56 (SPD) or I10-19 (+S) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [10/2014 - 09/2016]  , or refer to  PROBLEM SYMPTOMS TABLE [09/2016 - 09/2017] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR