1. Verify Sensor Condition and Cleanliness

• Before starting the calibration process, ensure that all parking sensors are clean and free from dirt, debris, or obstruction.
• Inspect the sensors for any signs of physical damage, as malfunctioning sensors may need to be replaced rather than calibrated.

2. Access Diagnostic System

• Connect a compatible OBD-II diagnostic tool to the vehicle's diagnostic port, usually located under the dashboard near the steering wheel.
• Turn on the ignition without starting the engine.
• Launch the diagnostic tool’s software, selecting the 2020 Mercedes-Benz C-Class model.

3. Select Parking Sensor Calibration

• Navigate through the diagnostic tool's menu to locate the parking sensor/calibration settings. This may be listed under the vehicle's body control module or similar section depending on the tool.

4. Follow On-Screen Instructions

• The diagnostic tool will provide step-by-step instructions on how to carry out the calibration process. Follow these instructions carefully.
• Typically, the tool will require the vehicle to be parked on a flat, level surface and may ask for adjustments in parking positions to ensure all sensors are accurately calibrated.

5. Perform a Sensor Test

• After calibration, use the diagnostic tool to test each of the parking sensors to ensure they are functioning correctly.
• Tests may include measuring the distance response of each sensor to a nearby object, ensuring they provide accurate readings.

6. Save Calibration Settings

• Once the calibration test is complete and the sensors are working correctly, save the new calibration settings using the diagnostic tool.
• Confirm that there are no remaining error codes related to the parking sensors.

7. Disconnect Diagnostic Tool

• Turn off the ignition and disconnect the diagnostic tool from the OBD-II port.

8. Final Test

• Start the vehicle and perform a practical test of the parking sensors by parking in and out of several spots, ensuring that the sensors respond appropriately to nearby objects.
• Monitor for any unusual behavior or alerts from the parking assist system.

9. Consult a Professional

• If the parking sensors are still not functioning correctly after the calibration, it may be necessary to consult a certified Mercedes-Benz technician for further diagnosis and potential sensor replacement.