Toyota Tacoma (2015-2018) Service Manual: Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter

Toyota Tacoma (2015-2018) 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 the respective systems based on the pulse signal.
If a short occurs in any of the ECUs or in the wire harness connected to an ECU, related components will not operate normally.

WIRING DIAGRAM

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 C9-40 (+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	C9-40 (+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.	CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - COMBINATION METER ASSEMBLY)

(a) Disconnect the S23 stereo component amplifier assembly connector.

(b) Disconnect the C9 combination meter assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
S23-11 (SPD) - C9-40 (+S)	Always	Below 1 Ω

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPAIR OR REPLACE HARNESS OR CONNECTOR

AVC-LAN Circuit

DESCRIPTION Each unit of the navigation system connected to the AVC-LAN (communication bus) transfers the switch signals using the AVC-LAN. If a short to +B or short to ground occurs in the AVC-LA ...

Microphone Circuit between Microphone and Radio Receiver

DESCRIPTION The navigation receiver assembly and telephone microphone assembly are connected to each other using the microphone connection detection signal lines. Using this circuit, the navigatio ...

Other materials:

Rear Combination Light Assembly
Components COMPONENTS ILLUSTRATION Disassembly DISASSEMBLY CAUTION / NOTICE / HINT HINT: Use the same procedure for both the LH and RH sides. The procedure described below is for the LH side. PROCEDURE 1. REMOVE TAIL AND TURN SIGNAL LIGHT BULB (a) Turn th ...

No Signal from Transmitter ID1 (C2121/21-C2124/24,C2181/81-C2184/84)
DESCRIPTION The tire pressure warning valve and transmitters that are installed in the tire and wheel assemblies measure the tire pressure of each wheel. The measured values are transmitted to the tire pressure warning ECU and receiver in the vehicle as radio waves. The ECU compares the measu ...

Inspection
INSPECTION PROCEDURE 1. INSPECT COOLER (ROOM TEMPERATURE. SENSOR) THERMISTOR (a) Check the resistance. (1) Measure the resistance according to the value(s) in the table below. Text in Illustration *a Component without harness connected (coo ...