Calibrate inaccurate speed

If you believe that the speedometer in your 1995 Buick Century Special 2.2L is inaccurate, there could be a few potential reasons for this issue. Here are some steps you can take to diagnose and potentially resolve the problem:

1. Check Tire Size: Incorrect tire size can affect the accuracy of your speedometer. Make sure that the tires on your car are the correct size as specified in the owner's manual. If you've recently changed the tires, the new size might not match the original specifications.
2. Inspect Speed Sensor: The speedometer gets its information from a speed sensor, usually located on the transmission. If this sensor is faulty or damaged, it could lead to inaccurate speed readings. Inspect the sensor for any visible damage or wiring issues.
3. Test Speedometer Calibration: There's a possibility that the speedometer itself is out of calibration. You might need a professional mechanic or an automotive specialist with the right tools to recalibrate the speedometer to ensure it's accurate.
4. Check for Faulty Wiring: Wiring issues can disrupt the signals between the speed sensor and the speedometer. Inspect the wiring for any signs of damage, corrosion, or loose connections.
5. Scan for Error Codes: Modern vehicles, even those from the 1990s, often have onboard diagnostic systems that can store error codes related to various components, including the speed sensor. Use an OBD-II scanner or visit a mechanic to check if any error codes are present.
6. Mechanical Issues: Mechanical problems in the transmission or drivetrain can affect the accuracy of the speedometer. If there are issues with these components, they might need to be inspected and repaired.
7. Consult a Professional: If you're not comfortable diagnosing or repairing the issue yourself, it's advisable to take your car to a qualified mechanic or automotive technician. They have the experience and tools to properly diagnose and fix the problem.

Remember that an inaccurate speedometer isn't just an inconvenience; it could also lead to legal and safety issues if you're not aware of your actual speed while driving. It's important to address this issue promptly.

There could be several reasons why your Edge 491 recumbent bike is not monitoring speed or distance and is only displaying 0. Here are a few troubleshooting steps you can try:

1. Check the sensor: Make sure the sensor on the bike is properly aligned and free of dirt and debris. The sensor is usually located near the flywheel or on the wheel hub.
2. Check the wiring: Ensure that all the wiring between the sensor and the display console is properly connected and not damaged.
3. Check the batteries: Make sure the batteries in the display console are fresh and properly installed. Low batteries can cause inaccurate readings or prevent the display from working altogether.
4. Calibrate the bike: Some bikes require calibration to ensure accurate speed and distance readings. Consult the user manual for instructions on how to calibrate your specific bike model.

If none of these steps resolve the issue, there may be a problem with the sensor or display console. In that case, you may need to contact the manufacturer for further assistance or consider taking the bike to a repair technician.

You need the speedo calibrated, if that is not the cause then either the speedo is defective or their is some unlikely problem with the speed sensor.

adjust the speed sensor, see the diagram, clean it, and tight the connector very well.
However RUN the software calibration, for diagnostic, troubleshooting, and fix it.

The Steps for Newer Style Console Calibration:

1. Locate the calibration area on the rear or underside of the console (a hole, near the console's center, that goes through to the electronics board. (This hole should not have a screw in it.)
   

2. Insert a pencil (eraser end), into the hole and feel around for the cal button (will click when pressed).
   

3. Press the button 2 times (with the pencil eraser). The first click should show CL11 in the console, the second click should show CL21.
   

4. If the process was done correctly, and CL21 appears in the console, you are in "calibration mode." The next few steps consists of pressing buttons on the console and observing settings. This will not require any other tools.
   

5. Press ENTER. CL22 should display in the TIME window and (??) in the SPEED window.
   

6. Press ENTER. CL23 should display in the TIME window and (??) in the SPEED window.
   

7. Press ENTER. CL24 should display in the TIME window and (??) in the SPEED window.
   

8. Press ENTER. CL25 should display in the TIME window and (??) in the SPEED window.
   

9. Press ENTER. CL26 should display in the TIME window. You should then see the letter "E."
   

10. Press ENTER. You should see "SS" or "55" in the console.
    

11. Push the STOP/START button. For safety, at this point, you should step off, or be off, the treadmill.
    

12. Push the ENTER button. The walking belt should start to move, accelerate to maximum speed, then stop on its own.
    

13. When the belt stops, the incline should self test by raising to its highest incline position, then lowering back down to its lowest position.
    

14. Once the incline test is complete, push the POWER button 2 times. The unit should shut off and the console should go completely blank. If this happens, the treadmill is done calibrating and is ready for use.
    

If the letter "F" appears in the SPEED or INCLINE window when the power button is pressed 2 times, the treadmill is indicating a failure somewhere either in the SPEED or INCLINE (depending on the window the "F" appeared in). Troubleshooting the failure would be the next step. The Calibration seq

I'm not sure why you need it calibrated if your Docotor says it's accurate but here is a web site link....

I hope this helps.
http://www.omronhealthcare.com/product/s1-1126-186-manual-monitor