How to Check Bad Parking Sensors: 5 Ways to Test Park Assist Sensors

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Parking sensors are the little devices that tell you where your car is in relation to a curb or other vehicle. They warn you when it’s getting too close, and they provide guidance as well. Not all cars have these nifty gadgets anymore, but if yours does, then this article will give some tips for testing them!

Parking sensors usually work without incident and rarely fail outright; however, there might be times when parking sensor problems crop up from time to time which can make driving difficult at best – not being able to see anything coming towards me makes things tricky enough on its own!

Electromagnetic parking sensor Vs ultrasonic

How do ultrasonic parking sensors work?

Ultrasonic sensors emit ultrasonic waves, which reflect off any object in their path. When the sensor catches a reflection, it sends information to its main unit about how far away that object is based on the difference of time for each wave’s arrival back at the sensor. 

How do electromagnetic parking sensors work?

Electromagnetic parking sensors are more modern and reliable but quite expensive, so they’re not as common as ultrasound ones which have been around since before we could even see them. These sensors are more modern and reliable than their predecessors, but they’re also quite expensive. They’re so rare that most people won’t know what it means to see one on a car!

Learn more about Parking sensors From Wikipedia

Electromagnetic parking sensor Vs ultrasonic

Parking sensor malfunctions and preventions

  • Corrosion, moisture enters the housing

The parking sensor housing is not immune to corrosion and moisture. This can lead both the sensors themselves and the wiring that connects them in place to malfunction without warning.

The detrimental effects of humidity on metal items are common knowledge – but it may come as a surprise that so-called “smart” technologies like park assist systems are also susceptible!


A good way to remove rust from the metal housing is by using WD40. The water-dispersant in the spray will dissolve any corrosion on your parking sensor area and make it look new again!

Just take a can of WD 40 with you when going shopping for groceries so that if there’s ever an issue where corrosion has caused some damage, you’ll be prepared and know what to do at home – all without breaking into full panic mode because now we’re talking about how important keeping things running smoothly really are not just inside our homes but outside too.

  • Failing electronic component of the sensor

The sensor’s failing components have been a cause of concern for researchers. The systematic failure of the parking sensors’ electronic component is troubling scientists because it could lead to an unreliable result that might be difficult to detect in time, which could harm your vehicle relying on its accuracy.


Here are some things to remember if your car’s sensor is working perfectly, but you still have a problem. You’ll need the owner’s manual for your vehicle, which will list all the error codes that could pop up on it and how to fix them–sometimes there might be more than one set of instructions because they vary by year or make/model. Hook up a code reader (which hooks directly into an OBD port), then find out what happened with an error message appearing on the screen; this may mean you need new wiper blades instead of needing major repairs like replacing sensors!

  • Low-quality parking sensor

Parking sensors are a key component in safe and efficient parking. They help drivers find available spaces, detect when the car is approaching another vehicle or an object too closely, and prevent collisions with curbs. However, the low-quality systems may lead to malfunctions that can affect safety for both drivers and other vehicles on the roadways.


When you’re driving in an unfamiliar area, the parking sensor is your best friend. It tells you when there’s a spot available and also alerts drivers of nearby obstacles or other cars that may be blocking their way to it.

Note: People often ask, what’s the best parking sensor on the market? I think, EKYLIN Auto Vehicle Reverse Backup Radar System meets your expectation with 4 Parking Sensors Distance Detection, LED Distance Display & Sound Warning.   

5 ways to check bad parking sensors

1. Checking parking sensors with “Multimeter”


Parking sensors are an important safety feature of a car. Most reliable way to check their accuracy? Use a multimeter! To do this, you need the tester set to electrical resistance measurement mode and have removed the parking sensor from your vehicle. The two most common types of parking sensors are 3-contact (pink wire) or 4-wire with ground straight ahead in the front bumper). When checking for faults using the said tool, there must be no break or short circuit at all these connections – else, and they will not function as desired when installed on the vehicle again and can even lead one into danger if they malfunction during driving while exiting garage!

In the case of a parking sensor, certain specifications must be met for it to function properly. For example, resistances between “plus” and minus should be more than 0.5 mega ohms (the higher – the better). Between the signal contact plus or minus contact resistance will depend on how bad your parking sensors are, but generally, they should not exceed 2-40 kilo-ohm, respectively.

2. Checking for Tactile 

The first thing you should do to check the parking sensors is found a quiet place where it’s okay if your car stalls. You can start with checking the rear sensor by putting it in reverse and have someone else drive ahead of you for a set distance while holding their brakes down. Now slowly let off on your brake pedal to back up until they detect something behind them (ie: an object). To test front sensors, engage 1st gear or “drive mode,” then put another person into driving position and tell them to hold down their breaks as well before proceeding forward at a safe speed.

The sensor is a small, barely detectable device that emits pulses of sound when an object approaches. The user can tell if the sensors are working by placing their fingers on it while they walk away from them and seeing how close before you hear another pulse until finally, none is coming at all as your walking farther out into the parking lot.

Unfortunately, we’ve discovered one or two bad parts in our system which have been causing some problems with detecting where objects are near us- apparently, this has something to do with humidity levels and other environmental factors, but I’m not entirely sure about what those may be yet- so, for now, we’re going to need someone who knows electronics pretty well (I think) to help diagnose why these things aren’t working properly anymore.

3. Please check with a piezoelectric element

Parktronic sensors are essentially piezoelectric elements. The voltage applied changes their shape, and a reverse effect creates an electric charge when the sensor vibrates-which can be used for checking parking spaces to see if they’re occupied or not. To use this sort of system, you’ll need two LEDs in your car, which will alternate light depending on whether there is contact with any obstructions under it by using a shielded wire that connects to the output of your new Parktronic sensor. First, wipe down its membrane and attach it securely. Normally when people try to touch them, and nothing happens, it means there is no electricity running through them, so if your vehicle does have power flowing, then all those LED lights will light up!

4. Check the parking sensors with a voice recording app on a Smartphone

voice recording app on a Smartphone

Parking sensors are meant to help drivers find a space, but they’re often hidden or too quiet for the human ear. To diagnose their function properly and without having to buy anything extra, some people have been using voice recorders on smartphones in order to listen back later when away from the problem area.

For diagnostics, it’s best to do this in a very quiet place with the recording app activated. Recording for thirty seconds should be enough time to detect whether or not your sensor is functioning properly. At the end of listening back, you will see signals on the chart from a working parking sensor if one exists, and an audible signal indicates no activation otherwise.

5. Checking bad parking sensors with scanner 

ELM327 USB Scanner for Ford and Mazda

Electronic scanners are an easy way to diagnose parking sensors. To start, you need a portable scanner on the ELM327 chip and diagnostic software installed on your Smartphone, such as the popular program ELM Config. Clicking PAM in English will provide instructions about where errors may be found or why they exist for different car systems, including the sensor readings of parking spaces.


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