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HOMESERVICE MANUALSPONTIAC1991FIREBIRD FORMULA, 5.0 F, STANDARD, M39REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 15 (ENGINE CONTROLS - TESTS W/CODES - 3.1L PFI)PCM/BCM CODE CHARTSCODE 24, VEHICLE SPEED SENSOR (VSS) "W" BODYNOTES
1991 Pontiac Firebird Formula, 5.0 F, Standard, M39

Code 24, Vehicle Speed Sensor (VSS) "W" Body: Notes

1991 Pontiac Firebird Formula, 5.0 F, Standard, M39SECTION Notes
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1992 Pontiac Sunbird, 1992 Pontiac Grand Prix, 1992 Pontiac Firebird, 1992 Oldsmobile Cutlass Supreme, and 1992 Chevrolet Lumina. However, it is still accessible from the selected car via links, so may be relevant.

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.
RENDER: 1.0x

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