Toyota Camry owners & service manuals

Toyota Camry (XV70): Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter

Toyota Camry Repair Manual XV70 (2018-2024) / Audio, Visual, Telematics / Audio / Video / Audio And Visual System / Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter

DESCRIPTION

for Automatic Sound Levelizer (ASL):
  • This circuit is necessary for the Automatic Sound Levelizer (ASL) built into the radio and display receiver assembly.

    The Automatic Sound Levelizer (ASL) function automatically adjusts the audio system volume in order to compensate for increased vehicle noise (vehicle noise tends to increase as vehicle speed increases). The ASL adjusts the volume based on vehicle speed signals sent from the combination meter assembly.

for "Bluetooth":
  • Vehicle speed signals are sent from the combination meter assembly and used to cancel "Bluetooth" function operation.

    The radio and display receiver assembly recognizes that the vehicle is being driven and makes it impossible to connect or register a "Bluetooth" device while driving.

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 system 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

CAUTION / NOTICE / HINT

NOTICE:

  • Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed. Refer to Precaution for Audio and Visual System.

    Click here

  • When replacing the radio and display receiver assembly, always replace it with a new one. If a radio and display receiver assembly which was installed to another vehicle is used, the following may occur:
    • A communication malfunction DTC may be stored.
    • The radio and display receiver assembly may not operate normally.

PROCEDURE

1.

CHECK VEHICLE SIGNAL (OPERATION CHECK)

(a) Enter the "Vehicle Signal Check Mode" screen. Refer to Check Vehicle Signal Check Mode in Operation Check.

Click here

(b) While driving the vehicle, compare the value displayed for "SPEED" to the reading on the speedometer. Check if these readings are almost equal.

HINT:

The combination meter assembly receives the vehicle speed signal from the skid control ECU via CAN communication. Therefore, perform the following inspection referring to values on the Data List of the skid control ECU because it is the source of the vehicle speed signal.

OK:

Vehicle speed displayed on the "Vehicle Signal Check Mode" screen is almost the same as the actual vehicle speed measured using the Techstream.

w/ Electric Parking Brake System: Click here

w/o Electric Parking Brake System: Click here

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

2.

INSPECT 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 K21-6 (+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

K21-6 (+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

3.

INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY (INPUT WAVEFORM)

(a) Check the input waveform.

(1) Remove the radio and display receiver assembly with the connector still connected.

(2) Connect an oscilloscope to terminal K3-27 (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

K3-27 (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

(Radio and Display Receiver Assembly)

OK

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

    READ NEXT:

     Steering Pad Switch Circuit

    DESCRIPTION This circuit sends an operation signal from the steering pad switch assembly to the radio and display receiver assembly. If there is an open in the circuit, the audio system cannot be op

     Illumination Circuit

    DESCRIPTION Power is supplied to the radio and display receiver assembly and steering pad switch assembly illumination when the light control switch is in the tail or head position. WIRING DIAGRAM

     Parking Brake Switch Circuit

    DESCRIPTION This circuit is from the parking brake switch assembly*1 or skid control ECU (Brake Actuator Assembly)*2 to the radio and display receiver assembly. *1: w/o Electric Parking Brake Sys

    SEE MORE:

     How To Proceed With Troubleshooting

    CAUTION / NOTICE / HINT HINT: Use the following procedure to troubleshoot the Entune system. *: Use the Techstream. PROCEDURE 1. VEHICLE BROUGHT TO WORKSHOP NEXT 2. CHECK THE CUSTOMER'S CONTRACT STATUS (a) Check if the satellite r

     Right Rear Wheel ABS Hold Solenoid Control Circuit Short to Battery (C12E712,...,C12F249)

    DESCRIPTION The ABS solenoid relay and solenoid valves are built into the brake actuator assembly. The rear solenoid valve RH controls the brake fluid pressure of the rear wheel cylinder RH of the vehicle. When this DTC is stored, the fail-safe function operates and the ABS solenoid relay is tur

    © 2023-2024 Copyright www.tocamry.com