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Vehicle Speed Sensor
- Vehicle speed sensor is mounted in rear of instrument panel. Sensor uses a reed switch to indicate vehicle speed. When speedometer cable rotates, magnet on end of speedometer shaft rotates, which opens and closes ECM signal to ground 4 times per cable revolution.
- Frequency to ground depends on speedometer shaft rotation and vehicle speed. If a vehicle speed sensor failure exists, a Code 42 will be set in ECM memory. For vehicle speed sensor diagnosis, G - TESTS W/ CODES article in this section.