Vehicle Speed Signal Circuit between Navigation ECU and Combination Meter [11/2017 - ]: 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 O3-19 (+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
      Measurement terminal	O3-19 (+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  Speed Signal Circuit [11/2017 - 09/2020]  , or refer to  Speed Signal Circuit [09/2020 - ] 

Result: 

OK 

See step  2

1. Disconnect the O150 navigation ECU connector.
2. Disconnect the O3 combination meter assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   O150-9 (SPD) - O3-19 (+S)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2017 - 03/2019]  , or refer to  PROBLEM SYMPTOMS TABLE [03/2019 - 09/2020]  , or refer to  PROBLEM SYMPTOMS TABLE [09/2020 - 01/2023]  , or refer to  PROBLEM SYMPTOMS TABLE [01/2023 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR