NAVIGATION SYSTEM Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter

DESCRIPTION

for Navigation Function:

• The radio and display receiver assembly receives a vehicle speed signal from the combination meter assembly and sends the signal to extension module.

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 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":

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

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

WIRING DIAGRAM

PROCEDURE

1. CHECK VEHICLE SIGNAL (OPERATION CHECK)

   
   

   1. 

      Enter the "Vehicle Signal Check Mode" screen. Refer to Check Vehicle Signal Check Mode in Operation Check Click here.

   2. While driving the vehicle, compare the "SPEED" indicator to the reading on the speedometer. Check if these readings are almost equal.

      Tech Tips

      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 GTS (See page Click here).

   
   

   OK

   PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

   NG

2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)

   
   

   1. Check the output waveform.

      

      
      

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

      2. Connect an oscilloscope to terminal F1-6 (+S) and body ground.

      3. Turn the ignition switch to 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	F1-6 (+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.

         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.

         Text in Illustration

         *a	Component with harness connected (Combination Meter Assembly)

   
   

   NG

   GO TO METER / GAUGE SYSTEM Click here

   OK

3. INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY (INPUT WAVEFORM)

   
   

   1. Check the input waveform.

      

      
      

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

      2. Connect an oscilloscope to terminal F69-17 (SPD) and body ground.

      3. Turn the ignition switch to 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	F69-17 (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.

         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.

         Text in Illustration

         *a	Component with harness connected (Radio and Display Receiver Assembly)

   
   

   OK

   REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY Click here

   NG

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

   
   

   1. Disconnect the F69 radio and display receiver assembly connector.

   2. Disconnect the 3A junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition F69-17 (SPD) - 3A-16 Always Below 1 Ω

   
   

   OK

   REPAIR OR REPLACE HARNESS OR CONNECTOR (JUNCTION CONNECTOR)

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - JUNCTION CONNECTOR)