Toyota Venza: Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter

Toyota Venza Service Manual / Navigation / Multi Info Display / Navigation System / 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 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

1. for 1AR-FE

2. for 2GR-FE

PROCEDURE

1.	INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

(a) Check the output waveform.

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

(2) Connect an oscilloscope to terminal E1-16 (+S) and body ground.

(3) Turn the ignition switch to ON.

(4) Turn a wheel slowly.

(5) Check the signal waveform according to the condition(s) in the table below.

Item	Condition
Measurement terminal	E1-16 (+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.

Text in Illustration

*a	Component with harness connected (Combination Meter Assembly)

GO TO METER / GAUGE SYSTEM

2.	INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (INPUT WAVEFORM)

(a) Check the input waveform.

(1) Remove the stereo component amplifier assembly with the connector(s) still connected.

(2) Connect an oscilloscope to terminal E14-11 (SPD) and body ground.

(3) Turn the ignition switch to ON.

(4) Turn a wheel slowly.

(5) Check the signal waveform according to the condition(s) in the table below.

Item	Condition
Measurement terminal	E14-11 (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.

Text in Illustration

*a	Component with harness connected (Stereo Component Amplifier Assembly)

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

3.	CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - JUNCTION CONNECTOR)

(a) Disconnect the E14 stereo component amplifier assembly connector.

(b) Disconnect the E31 junction connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
E14-11 (SPD) - E31-21	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - JUNCTION CONNECTOR)

(a) Disconnect the E1 combination meter assembly connector.

(b) Disconnect the E31 junction connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
E1-16 (+S) - E31-19	Always	Below 1 Ω

REPLACE JUNCTION CONNECTOR

REPAIR OR REPLACE HARNESS OR CONNECTOR

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