Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter [06/2018 - 09/2022]: Description

WARNING: This page is about a different car, the 2022 Lexus ES 300h, 2021 Lexus ES 300h, 2020 Lexus ES 300h, and 2019 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

The stereo component amplifier assembly receives a vehicle speed signal from the combination meter assembly to control the ASL function.

HINT:

A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter assembly. The signal is changed to a pulse signal at the transistor in the combination meter assembly. Each ECU controls its respective systems based on this pulse signal.
If a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems in the following diagram will not operate normally.