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Home >> Honda >> 1987 >> Prelude Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Feedback Carburetor System >> Trouble Shooting >> Speed Sensor
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Speed Sensor

  1. Raise and support front of vehicle. Insert voltmeter or test light positive probe into Yellow and Black (Accord) or Yellow/Black (Civic and Prelude) wire terminal at control unit connector.
  2. Connect negative probe to ground. Start engine. Place vehicle in 2nd gear and accelerate slowly. Check for battery voltage as shown in table.
    SPEED SENSOR VOLTAGE CHECK

    Speed Voltage
    Accord
    Below 10 MPH Yes
    Above 20 MPH No
    Civic
    Below 6 MPH Yes
    Above 12 MPH No
    Prelude
    Below 11 MPH Yes
    Above 16 MPH No
  3. If voltage does not correspond to above MPH ranges, install a new speed sensor and retest. If voltage was not present during step 2), check for bad electrical connection, fuse or faulty speed sensor. Replace or repair as necessary and retest.