Code 24: Vehicle Speed Sensor: Notes
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1990 Pontiac Grand Prix, 1990 Pontiac Grand Am, 1990 Oldsmobile Cutlass Supreme, 1990 Oldsmobile Cutlass Calais, and 1990 Chevrolet Beretta. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
On vehicles with automatic transmission, a faulty or improperly adjusted park/neutral switch can result in a false Code 24. Use a "Scan" tester and check for proper signal while in Drive. Refer to SYSTEMS & COMPONENT TESTING article in this section for P/N switch diagnosis.
- Code 24 will set (with vehicle speed less than 2 MPH) only if the following conditions are met:
- Engine RPM is between 1600 and 3600.
- TPS is greater than 7 percent.
- Gear selector not in Park or Neutral.
- All conditions met for 20 seconds.
- No Codes 21 or 22.
Above conditions are met during road load deceleration. Ignore Code 24 sets when drive wheels are not turning faster than 3 MPH. PM generator only produces a signal if drive wheels are turning greater than 3 MPH.
- Ensure correct MEM-CAL is used before replacing ECM.