WIPER AND WASHER SYSTEM(w/ Rain Sensor) Speed Signal Circuit

DESCRIPTION

The windshield wiper relay assembly receives a vehicle speed signal from the combination meter to control the automatic windshield wiper system.

A voltage of 12 V or 5 V is output from the combination meter assembly and then input to the skid control ECU.

A voltage of 12 V or 5 V is output from each ECU or relay 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.

If a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems in the diagram below will not operate normally.

WIRING DIAGRAM


  1. A005GEEE02

PROCEDURE


  1. CHECK COMBINATION METER SYSTEM


    1. The circuit that sends vehicle speed signals to the combination meter system is inspected in the meter section Click here.


    NEXT

  2. CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY ASSEMBLY - COMBINATION METER ASSEMBLY)


    1. Disconnect the F72 windshield wiper switch assembly connector.

    2. Disconnect the F1 combination meter connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F72-24 (SPD) - F1-6 (+S) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT COMBINATION METER ASSEMBLY (SPEED SENSOR SIGNAL)


    1. A005JUME02
      Text in Illustration
      *a

      Component with harness connected

      (Combination Meter)

      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.

      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 Driving at approx. 20 km/h (12 mph)
        OK
        The waveform is displayed as 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) shown in the illustration narrows.


    OK

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

    NG

    REPLACE COMBINATION METER ASSEMBLY Click here