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Home >> Honda >> 1985 >> Prelude Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Anti-AFTERBURN System >> Component Testing >> Speed Sensor
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Speed Sensor

  1. Raise and support front of vehicle. Push voltmeter or test light positive probe into Yellow/Black wire (Yellow wire on Accord) terminal at control unit connector.
  2. Connect negative probe to ground. Start engine. Place vehicle in 2nd position (gear selector in "2" position) and accelerate slowly. Battery voltage should be as shown in SPEED SENSOR VOLTAGE CHECK table.
    SPEED SENSOR VOLTAGE CHECK

    Speed Voltage
    Below 11 MPH Yes
    Above 16 MPH No
  3. If voltmeter readings do not correspond to appropriate MPH ranges, install a new speed sensor and retest. If there was no voltage during speed sensor test, check for bad electrical connection, fuse or faulty speed sensor. Replace or repair as necessary and retest.