Parking Sensor Not Working? Causes and Fixes

Parking sensors that stop working, or beep constantly when nothing is there, are usually dirty, wet, iced or blocked. Mud, road film and water droplets after a car wash can all fool them, and so can a tow bar or bike rack. If cleaning does not fix it, one sensor or its wiring has probably failed.

Quick checks

1. Clean and dry every sensor: wipe off dirt and water. After a car wash or heavy rain, wait for them to dry.
2. Check the system is on: many cars have a button that switches the sensors off, and some switch off when a trailer is plugged in.
3. Remove anything in the way: a tow ball, bike rack or number plate frame in front of a sensor can cause constant beeping.
4. Look for damage: a cracked sensor, one pushed into the bumper, or one painted over after bodywork will not read properly.

Finding a failed sensor

With the car in reverse and the handbrake on, put your fingertip lightly on each sensor. A working sensor usually ticks or vibrates very slightly. One that is silent or behaves differently from the others is the suspect. Many systems also beep a warning or show an error when a sensor fails.

Wiring and the control unit

Sensor wiring runs behind the bumper, where it can corrode or be damaged in a small knock. On aftermarket systems, the control unit often takes power from the reverse light, so a blown fuse or a change to the reverse light wiring can stop the whole system.

When to get help

If cleaning fixed it, you are done. If one sensor stays silent or the system shows an error, the sensor or wiring needs testing. We fit and repair parking sensors at your home or work: see parking sensors installation. A reverse camera pairs well with sensors, and our reverse camera guide explains the options.

Frequently asked questions

Why are my parking sensors beeping constantly?

Something is in front of a sensor: dirt, water, ice, a tow bar or bike rack. If cleaning does not stop it, one sensor may be faulty.

Why do my parking sensors not work after a car wash?

Water droplets on the sensors confuse them. They usually work again once they are dry.

Can one faulty sensor stop the whole system?

On many systems, yes. The car may switch the sensors off and show a warning when one fails.

Can parking sensors be added to a car without them?

Yes. Aftermarket sensors are fitted into the bumper and wired to a small control unit and a beeper or display.