RX400h · Service Manual BODY ELECTRICAL

Vehicle Speed Signal Circuit between Multi-display and Combination Meter

Circuit diagnosis

DESCRIPTION

The multi-display performs switch operation control during driving by receiving a vehicle speed signal from the combination meter.

HINT:
  1. A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter. The signal is changed to a pulse signal at the transistor in the combination meter. Each ECU controls the respective system based on the pulse signal.
  2. If a short occurs in an ECU, all systems in the diagram below will not operate normally.


WIRING DIAGRAM

E111741E02

INSPECTION PROCEDURE


1. CHECK OPERATION OF SPEEDOMETER

  1. Drive the vehicle and check if the function of the speedometer in 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 COMBINATION METER SYSTEM
OK


2. INSPECT MULTI-DISPLAY

  1. E111725E07
    Disconnect the multi-display connector M1.

  1. Measure voltage.

    1. Jack up either one of the drive wheels.

    2. Move the shift lever to the neutral position.

    3. Turn the ignition switch to the ON position.

    4. E110855E01
      Measure the voltage between terminal SPD of the multi-display and body ground when the drive wheels are turned slowly.

      OK:
      Voltage pulses as shown in the illustration.



 OK
REPLACE MULTI-DISPLAY
NG


3. CHECK HARNESS AND CONNECTOR (COMBINATION METER - MULTI-DISPLAY)

  1. E111764E02
    Disconnect the multi-display connector M1 and combination meter connector C8.

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

    Resistance:
    Tester connection
    		 Condition
    		 Specified condition
    SPD - C8-6
    		 Ignition switch OFF
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - MULTI-DISPLAY)

  1. E111764E02
    Disconnect the multi-display connector M1 and combination meter connector C8.

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

    Resistance:
    Tester connection
    		 Condition
    		 Specified condition
    SPD - Body ground
    		 Ignition switch OFF
    		 10 kΩ or higher

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



 NG
REPAIR OR REPLACE HARNESS OR CONNECTOR OR EACH ECU
OK

REPLACE COMBINATION METER


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