Vehicle Speed Signal Circuit between Navigation ECU and Combination Meter [06/2018 - 03/2019]: Procedure
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2023 Toyota GR Corolla, 2023 Toyota Corolla, 2022 Toyota Corolla, 2021 Toyota Corolla, and 2020 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)
- Check the output waveform.
*a Component with harness connected
(Combination Meter Assembly)- Remove the combination meter assembly with the connector(s) still connected.
- Connect an oscilloscope to terminal I4-36 (+S) and body ground.
- Turn the engine switch on (IG).
- Turn a wheel slowly.
- Check the signal waveform according to the condition(s) in the table below.
Item Condition Measurement terminal I4-36 (+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 [06/2018 - 01/2019] , or refer to Speed Signal Circuit [01/2019 - 04/2020]
Result:
OK
See step 2
- Check the output waveform.
- CHECK HARNESS AND CONNECTOR (NAVIGATION ECU - COMBINATION METER ASSEMBLY)
- Disconnect the I69 navigation ECU connector.
- Disconnect the I4 combination meter assembly connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition I69-9 (SPD) - I4-36 (+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 [06/2018 - 01/2019] , or refer to PROBLEM SYMPTOMS TABLE [01/2019 - 03/2019]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR