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:

Reassembly
REASSEMBLY PROCEDURE 1. INSTALL MASTER CYLINDER RESERVOIR GROMMET (a) Apply lithium soap base glycol grease to 2 new grommets. (b) Install the 2 grommets onto the brake master cylinder reservoir. 2. INSTALL BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY (a) Install the brake master cylinder reservoi ...

ABS Warning Light does not Come ON
DESCRIPTION Refer to ABS Warning Light Remains ON (See page ). WIRING DIAGRAM Refer to ABS Warning Light Remains ON (See page ). CAUTION / NOTICE / HINT NOTICE: When replacing the skid control ECU (master cylinder solenoid), perform calibration (See page ). Inspect the ...

Does not Play even after Bluetooth Audio Mode is Selected
CAUTION / NOTICE / HINT HINT: Even if the portable player can play audio content, it may not be able to play via the in-vehicle device. This does not necessarily indicate a malfunction of the in-vehicle device. PROCEDURE 1. CHECK OPERATION (a) Check if the po ...