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Home >> Chevrolet >> 1993 >> APV >> Repair and Diagnosis >> External Pages >> Different car >> Section 8 (Engine Controls - Tests W/Codes - 3.1L) >> ECM/Pcm Code Charts >> Code 24 - Vehicle Speed Sensor >> Notes
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Code 24 - Vehicle Speed Sensor: Notes

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Speed sensor, which is a Permanent Magnet (PM) generator, provides control module with vehicle speed information. PM generator, mounted in transmission, produces a pulsing AC voltage signal whenever vehicle speed is greater than 3 MPH. Voltage level and pulses increase with vehicle speed. Control module converts pulsing voltage to MPH, which is used by control module to calculate vehicle adjustments.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. Code 24 sets when MPH reads zero, transmission is not in Park or Neutral, engine speed indicates vehicle is in a cruise mode (1200-4400) RPM, TPS indicates closed throttle and MAP sensor senses high manifold vacuum. All of these conditions must be met for 2-5 seconds. PM generator only produces a voltage signal if drive wheels are turning greater than 3 MPH.
  2. Before replacing control module, PROM/MEM-CAL should be checked for correct application.
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