AUDIO AND VISUAL SYSTEM (w/o Navigation 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 receiver assembly.

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

for "Bluetooth":

• Speed signals are received from the combination meter assembly and used to cancel "Bluetooth" function operation.

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

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

   
   
   1. 

      Text in Illustration

      *a	Component with harness connected (Combination Meter Assembly)

      Check the output waveform.

      
      

      1. Remove the combination meter assembly with the connector still connected.

      2. Connect an oscilloscope to terminal H19-40 (+S) and body ground.

      3. Turn the power switch on (IG).

      4. Turn a wheel slowly.

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

         Item	Condition
         Measurement terminal	H19-40 (+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.

         Tech Tips

         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.

   
   

   NG

   GO TO METER / GAUGE SYSTEM Click here

   OK

2. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - COMBINATION METER ASSEMBLY)

   
   

   1. Disconnect the radio receiver assembly and combination meter assembly connectors.

   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      w/ Separate Type Amplifier (for 10 Speakers) Tester Connection Condition Specified Condition H52-3 (SPD) - H19-40 (+S) Always Below 1 Ω
      w/ Built-in Type Amplifier (for 6 Speakers) Tester Connection Condition Specified Condition H47-17 (SPD) - H19-40 (+S) Always Below 1 Ω

   
   

   NG

   CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - JUNCTION CONNECTOR) Click here

   OK

   REPLACE RADIO RECEIVER ASSEMBLY Click here

3. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - JUNCTION CONNECTOR)

   
   

   1. Disconnect the radio receiver assembly connector and junction connector.

   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      w/ Separate Type Amplifier (for 10 Speakers) Tester Connection Condition Specified Condition H52-3 (SPD) - H117-99 Always Below 1 Ω
      w/ Built-in Type Amplifier (for 6 Speakers) Tester Connection Condition Specified Condition H47-17 (SPD) - H117-99 Always Below 1 Ω

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

   GO TO METER / GAUGE SYSTEM Click here