Lexus RX (RX 350L, RX450h) 2016-2023 Repair Manual: Vehicle Speed Signal Circuit between Navigation ECU and Combination Meter

DESCRIPTION

The navigation ECU receives a vehicle speed signal from the combination meter assembly.

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.

WIRING DIAGRAM

PROCEDURE

1.

CHECK COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

(a) Check the output waveform.

(1) Remove the combination meter assembly with the connector still connected.

(2) Connect an oscilloscope to terminal J10-19 (+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

J10-19 (+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.

*a

Component with harness connected

(Combination Meter Assembly)

NG

GO TO METER / GAUGE SYSTEM

OK

2.

CHECK NAVIGATION ECU (INPUT WAVEFORM)

(a) Check the input waveform.

(1) Remove the navigation ECU with the connector(s) still connected.

(2) Connect an oscilloscope to terminal J153-9 (SPD) 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

J153-9 (SPD) - 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.

*a

Component with harness connected

(Navigation ECU)

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

    AVC-LAN Circuit
    DESCRIPTION Each unit of the audio and visual system connected to the AVC-LAN (communication bus) transmits switch signals via AVC-LAN communication. If a short to +B or short to ground occurs in the ...

    Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter
    DESCRIPTION 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 ea ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2023 Repair Manual > Audio And Visual System (for 12.3 Inch Display): GVIF Disconnected (from EMV/MM Integrated Device to Multi Display) (B1575)
    DESCRIPTION The radio receiver assembly and multi-display assembly are connected via video signal (digital) lines. This DTC is stored when a video signal (digital) line is disconnected. DTC No. Detection Item DTC Detection Condition Trouble Area B1575 GVIF Disconnected (from EMV/MM In ...

    Lexus RX (RX 350L, RX450h) 2016-2023 Repair Manual > Front Power Seat Control System (w/ Memory): Wireless Transmitter Memory Function does not Operate
    DESCRIPTION With the engine switch on (IG) and the driver door closed, pressing the manual lock or unlock switch on the multiplex network master switch assembly while holding a seat memory switch LH (M1, M2 or M3 switch) will register the transmitter recognition code into the seat memory switch LH t ...

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

    Chevrolet Trax (2013-2022) Owner's Manual

    © 2023 Copyright www.lexusrx.net
    0.017