Lexus ES manuals

Lexus ES: Vehicle Speed Signal Circuit between Navigation ECU and Combination Meter

Lexus ES (XZ10) Service Manual / Audio & Visual & Telematics / Navigation / Multi Info Display / Navigation System (for Gasoline Model) / 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 G17-19 (+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

G17-19 (+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.

INSPECT 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 G14-9 (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

G14-9 (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

READ NEXT:

 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

 Visual Mute Signal Circuit between Radio Receiver and Multi-display

DESCRIPTION The radio receiver assembly sends a visual mute signal to the multi-display assembly. As a result, a black screen is displayed when the screen changes so that noise and distorted images ar

 Voice Guidance does not Function

WIRING DIAGRAM PROCEDURE 1. CHECK VOICE GUIDANCE SETTING (a) Check that the voice guidance settings are not off. OK: Voice guidance settings are not off. NG CHANGE VOICE GUIDANCE SETT

SEE MORE:

 ENG / EHV Device (C1A40)

DESCRIPTION When a SFI system malfunction signal sent by the hybrid vehicle control ECU is detected by the clearance warning ECU assembly, DTC C1A40 is stored. DTC No. Detection Item DTC Detection Condition Trouble Area C1A40 ENG / EHV Device When the power switch on (IG), a SFI sys

 System Description

SYSTEM DESCRIPTION GENERAL (a) The rear window defogger wire (back window glass) is attached to the inside of the rear window and defogs the window surface quickly when the rear window defogger switch is pressed. The indicator light on the switch illuminates while the system is operating. This syste

© 2016-2024 Copyright www.lexguide.net