METER / GAUGE SYSTEM > Speed Signal Circuit

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DESCRIPTION

The combination meter assembly receives the vehicle speed signal from this circuit. The wheel speed sensors produce an output that varies according to the vehicle speed. The wheel speed sensor output is received by the skid control ECU which uses this information to create the vehicle speed sensor signal*a. The vehicle speed sensor signal consists of pulses sent to the combination meter assembly from the skid control ECU. To create this signal, 12 V is output from IG2 which is behind a resistor in the combination meter assembly. This voltage is sent to the skid control ECU. The pulse signal is created by switching the transistor in the skid control ECU on and off, making the voltage on the wire drop to 0 V. A similar system is used for the output of this signal from the combination meter assembly via terminal +S. A voltage of 12 V or 5 V is applied to terminal +S from each ECU or relay that is connected to this terminal. The transistor in the combination meter assembly is controlled by the signal from the skid control ECU. When this transistor is turned on, this transistor makes the voltage supplied by the various ECUs (via their respective internal resistors) drop to 0 V. Each ECU connected to terminal +S of the combination meter assembly controls its respective system based on the pulse signal.
  1. *a: This vehicle speed sensor signal is created by the skid control ECU. There is no actual component that is referred to as the vehicle speed sensor. In addition, for some other systems, vehicle speed information may be exchanged using CAN communication.

HINT:
This circuit is used for the systems connected to terminal +S. This signal is not used for combination meter assembly operation. Combination meter assembly components such as the speedometer operate using data received via CAN communication.


WIRING DIAGRAM


E217460E01


INSPECTION PROCEDURE

1.INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)


    E160303E89

  1. Disconnect the H19 connector.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    H19-40 (+S) - Body ground
    		Power switch on (IG)
    		4.5 to 14 V

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Combination Meter Assembly)

    HINT:
    If any of the ECUs specified in the wiring diagram supplies power to the combination meter assembly, the combination meter assembly will output a waveform.



NG
Go to step 5
OK


2.INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)

  1. Reconnect the H19 connector.



    C209401E56

  1. Disconnect the A61 connector.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A61-11 (SP1) - Body ground
    		Power switch on (IG)
    		11 to 14 V

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Skid Control ECU)



NG
Go to step 4
OK


3.INSPECT SKID CONTROL ECU (INPUT WAVEFORM)


    E159354E64

  1. Check the input waveform.

    1. Reconnect the A61 connector.

    2. Remove the combination meter assembly with the connector(s) still connected.

    3. Connect an oscilloscope to terminal H19-39 (SI) and body ground.

    4. Turn the power switch on (IG).

    5. Turn the wheel slowly.

    6. 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
      Text in Illustration 
      *a
      		Component with harness connected
      (Combination Meter Assembly)

      OK:
      The waveform is displayed as 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.

      Result:
      Result
      		Proceed to
      OK
      		A
      NG (for LHD)
      		B
      NG (for RHD)
      		C



B
REPLACE SKID CONTROL ECU (Click here)

C
REPLACE SKID CONTROL ECU (Click here)
A

REPLACE COMBINATION METER ASSEMBLY (Click here)  

4.CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU)

  1. Disconnect the H19 and A61 connectors.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A61-11 (SP1) - H19-39 (SI)
    		Always
    		Below 1 Ω
    A61-11 (SP1) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE COMBINATION METER ASSEMBLY (Click here)  

5.CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - JUNCTION CONNECTOR)

  1. Disconnect the junction connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H19-40 (+S) - H117-59
    		Always
    		Below 1 Ω
    H19-40 (+S) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


6.CHECK HARNESS AND CONNECTOR (JUNCTION CONNECTOR)


  1. Inspect for a short in the circuit that is connected to the junction block connector shown in the wiring diagram.

    HINT:
    If voltage is not present, it is possible that an ECU or circuit has a malfunction. The malfunctioning ECU or circuit will be diagnosed in the following steps.



    1. Disconnect the 3B connector.


      E217467E02

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

      Standard Voltage:
      Tester Connection
      		Condition
      		Specified Condition
      H117-29 - Body ground
      		Power switch on (IG)
      		4.5 to 14 V
      H117-19 - Body ground
      		Power switch on (IG)
      		4.5 to 14 V
      H117-89 - Body ground
      		Power switch on (IG)
      		4.5 to 14 V
      H117-58 - Body ground
      		Power switch on (IG)
      		4.5 to 14 V
      H117-79 - Body ground
      		Power switch on (IG)
      		4.5 to 14 V
      H117-99 - Body ground
      		Power switch on (IG)
      		4.5 to 14 V

      Text in Illustration 
      *a
      		Front view of wire harness connector
      (to Junction Connector)

      Result:
      Result
      		Proceed to
      Voltage is not present in one circuit.
      		A
      Voltage is present in all the circuits.
      		B



B
REPLACE JUNCTION CONNECTOR
A


7.SYSTEM CHECK

  1. Select the circuit for which voltage was not present in step 6.

    Result:

    Tester Connection
    		System that Uses the Circuit
    		Proceed to
    H117-29 - Body ground
    		Hybrid Control System
    		A
    H117-19 - Body ground
    		Wiper and Washer System*1
    		B
    H117-58 - Body ground
    		Lighting System*2
    		C
    H117-89 - Body ground
    		Audio/Visual System
    		D
    H117-99 - Body ground
    		Audio/Visual System
    		D
    H117-99 - Body ground
    		Navigation System*3 or *4
    		D

    1. *1: w/ Auto Wiper System
    2. *2: w/ Automatic Type Headlight Beam Level Control
    3. *3: w/ Navigation System (for DVD)
    4. *4: w/ Navigation System (for HDD)



B
Go to step 9

C
Go to step 10

D
Go to step 11
A


8.CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU CIRCUIT)

  1. Disconnect the H3 connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H3-14 (SPDI) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE POWER MANAGEMENT CONTROL ECU (Click here)  

9.CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY CIRCUIT)

  1. Disconnect the H75 connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H75-19 (SPD) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE WINDSHIELD WIPER RELAY ASSEMBLY (Click here)  

10.CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY CIRCUIT)

  1. Disconnect the A46 connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A46-16 (SPDR) - Body ground
    		Always
    		10 kΩ or higher

    Result:
    Result
    		Proceed to
    OK (for LHD)
    		A
    OK (for RHD)
    		B
    NG
    		C



B
REPLACE HEADLIGHT LEVELING ECU ASSEMBLY (Click here)

C
REPAIR OR REPLACE HARNESS OR CONNECTOR
A

REPLACE HEADLIGHT LEVELING ECU ASSEMBLY (Click here)  

11.SYSTEM CHECK

  1. Select the circuit for which voltage was not present in step 6.

    Result:

    Tester Connection
    		System that Uses the Circuit
    		Proceed to
    H117-89 - Body ground
    		Audio/Visual System
    		A
    H117-99 - Body ground
    		Audio/Visual System
    		B
    H117-99 - Body ground
    		Navigation System*1 or *2
    		B

    1. *1: w/ Navigation System (for DVD)
    2. *2: w/ Navigation System (for HDD)



B
Go to step 13
A


12.CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY CIRCUIT)

  1. Disconnect the H56*1 or H55*2 connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H56-2 (SPD)*1 - Body ground
    		Always
    		10 kΩ or higher
    H55-11 (SPD)*2 - Body ground
    		Always
    		10 kΩ or higher

    1. *1: w/ Navigation System
    2. *2: w/o Navigation System



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY (Click here)  

13.CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT, NAVIGATION RECEIVER CIRCUIT)

  1. Disconnect the H47*1, H52*2, or H60*3 connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H47-17 (SPD)*1 - Body ground
    		Always
    		10 kΩ or higher
    H52-3 (SPD)*2 - Body ground
    		Always
    		10 kΩ or higher
    H60-18 (SPD)*3 - Body ground
    		Always
    		10 kΩ or higher

    1. *1: w/o Navigation System, w/ Built-in Type Amplifier
    2. *2: w/o Navigation System, w/ Separate Type Amplifier
    3. *3: w/ Navigation System

    Result:
    Result
    		Proceed to
    OK (w/o Navigation System)
    		A
    OK (w/ Navigation System (for HDD))
    		B
    OK (w/ Navigation System (for DVD))
    		C
    NG
    		D



B
REPLACE NAVIGATION COMPUTER SUB-ASSEMBLY (Click here)

C
REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY (Click here)

D
REPAIR OR REPLACE HARNESS OR CONNECTOR
A

REPLACE RADIO RECEIVER ASSEMBLY (Click here)