AUDIO AND VISUAL SYSTEM (w/o Multi-display) > Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter

for Preparation Click here


DESCRIPTION

for Automatic Sound Levelizer (ASL):
  1. 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":
  1. 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.

HINT:
  1. 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 system based on the pulse signal.
  2. 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


for TMC Made 2ZR-FE

E217480E03


except TMC Made 2ZR-FE

E237375E01


except TMC Made 2AZ-FE

E237380E01


INSPECTION PROCEDURE

1.INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)


    E159354E66

  1. Check the output waveform.

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

    2. Connect an oscilloscope to terminal E46-36 (+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
      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)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (RADIO RECEIVER ASSEMBLY - JUNCTION BLOCK)
OK


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

  1. Disconnect the E114 radio receiver assembly connector (for 6 speakers (w/ USB audio system)).

  1. Disconnect the E26 radio receiver assembly connector (for 6 speakers (w/o USB audio system) or 4 speakers).

  1. Disconnect the E46 combination meter assembly connector.

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

    Standard Resistance:
    for 6 Speakers (w/ USB Audio System) 
    Tester Connection
    		Condition
    		Specified Condition
    E114-17 (SPD) - E46-36 (+S)
    		Always
    		Below 1 Ω
    for 6 Speakers (w/o USB Audio System) or 4 Speakers 
    Tester Connection
    		Condition
    		Specified Condition
    E26-3 (SPD) - E46-36 (+S)
    		Always
    		Below 1 Ω

  1. Proceed to the next step based on the inspection result.

    Result:
    Condition
    		Proceed to
    OK
    		A
    NG (for TMC made)
    		B
    NG (except TMC made)
    		C


B
Go to step 3

C
REPAIR OR REPLACE HARNESS OR CONNECTOR (RADIO RECEIVER ASSEMBLY - COMBINATION METER ASSEMBLY)
A

REPLACE RADIO RECEIVER ASSEMBLY (Click here)  

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

  1. Disconnect the E114 radio receiver assembly connector (for 6 speakers (w/ USB audio system)).

  1. Disconnect the E26 radio receiver assembly connector (for 6 speakers (w/o USB audio system) or 4 speakers).

  1. Disconnect the 4C junction block connector.

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

    Standard Resistance:
    for 6 Speakers (w/ USB Audio System) 
    Tester Connection
    		Condition
    		Specified Condition
    E114-17 (SPD) - 4C-1
    		Always
    		Below 1 Ω
    for 6 Speakers (w/o USB Audio System) or 4 Speakers 
    Tester Connection
    		Condition
    		Specified Condition
    E26-3 (SPD) - 4C-1
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (RADIO RECEIVER ASSEMBLY - JUNCTION BLOCK)
OK

GO TO METER / GAUGE SYSTEM (Click here)