Vehicle Speed Signal Circuit Between Radio Receiver and Combination Meter

AUDIO / VISUAL: AUDIO AND VISUAL SYSTEM: Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter

Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter

DESCRIPTION

This circuit is necessary for the ASL (Auto Sound Levelizer) built into the radio receiver. Speed signals are received from the combination meter and used for the ASL.
The ASL function automatically adjusts the sound data in order to enable hearing the clear audio even when vehicle noise increases (as vehicle noise increases, the volume is turned up, etc.).

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. OPERATION OF SPEEDOMETER
(a) Drive the vehicle and check if the function of the speedometer on the combination meter is normal.
OK:
Actual vehicle speed and the speed indicated on the speedometer are the same.
HINT: The vehicle speed sensor is functioning normally when the indication on the speedometer is normal.

NG -- GO TO METER / GAUGE SYSTEM
OK -- Continue to next step.

2. CHECK RADIO RECEIVER (SPD VOLTAGE)




(a) Disconnect the R5 receiver connector.
(b) Measure the voltage.
(1) Jack up either one of the drive wheels.
(2) Move the shift lever to the neutral position.
(3) Turn the power switch ON (IG).





(4) Measure the voltage between terminal SPD of the radio receiver and body ground when the drive wheels are turned slowly.
OK:
Voltage pulses as shown in the illustration.
OK -- REPLACE RADIO RECEIVER
NG -- Continue to next step.

3. CHECK WIRE HARNESS (COMBINATION METER - RADIO RECEIVER)




(a) Disconnect the R5 receiver connector.
(b) Disconnect the C10 meter connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

4. CHECK WIRE HARNESS (RADIO RECEIVER - BODY GROUND)




(a) Disconnect the R5 receiver connector.
(b) Measure the resistance of the wire harness side connector.
Standard resistance:





HINT: If the resistance between terminal SPD and body ground is less than 10 kOhms, there may be a short in a wire harness, connector, or an ECU that is connected to the SPD signal wire.

NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE RADIO RECEIVER