Updated at: 24-07-2022 - By: Lucas

Nowadays, all cars are equipped with parking sensors as a standard feature. Despite the fact that they rarely fail, it’s a good idea to know how to troubleshoot them if they do.

Parking sensors that aren’t working properly can be checked in a few simple methods. A multimeter, a smartphone, or even a simple tactile examination might be used for these tasks. Scanners are yet another viable option for conducting the examination.

Each technique will be discussed in detail in the following sections.

How do parking sensors work?

Parking sensor malfunctions

Ultrasonic and electromagnetic parking sensors are the most frequent. In order to work, ultrasonic parking sensors produce ultrasonic waves and capture their reflections from an object they encounter. The main unit uses the difference in radiation time to calculate the sensor’s distance from the interference.

Magnetic sensors are strips of tape that emit electromagnetic fields. It is applied to the inside of the front and back bumpers. Due to the high price tag, these sensors are only found in high-end vehicles where they are a must.

Parking sensor malfunctions

The Parktronic system may either not work at all or constantly beep, causing misleading alerts, if one or more sensors are damaged. The dashboard may indicate a parking sensor fault if the sensor wires are shortcircuited in rainy weather.

In other cases, automobile owners mistakenly believe that the problem is due to dirt on the sensor’s working surface or the fact that it was painted to match the color of the front or rear bumpers.

  • contact corrosion, moisture entering the housing through cracks;
  • failing electronic component of the sensor;
  • contamination of the working surface of the parking sensor;
  • mechanical damage to the sensor as a result of an accident, or impact;
  • damage to the wiring (especially typical for the front sensors due to dirt and chemicals);
  • manufacturing defect of the parking sensor, or its low quality (most often aftermarket, fake)

How to check the parking sensors?

Parking sensor malfunctions-3

There are four techniques to examine the ultrasonic parking sensors.

Electronic error scanners and electronic testers can be used in addition to tactile methods.

Tactile check

A visual assessment of the parking sensor is a good starting point. However, you must first start the engine and shift the transmission into first or reverse, not drive. While you inspect the sensors, you will need another person to conduct these actions in the car.

Put the gearshift in reverse to see if the rear parking sensors are working. To check the front sensors, put the vehicle in drive or put it in first gear if it’s a manual transmission.

This sensor can detect when an object is in close proximity to it by emitting barely audible clicking sounds (about 510 clicks per second) (it is easiest to check with your finger).

The sensor should vibrate slightly if you place your finger on it. You’ll get a better sense of vibration if you slide your finger over it a little.

Check each parking sensor after that. The spouse in the cabin should also keep an eye on how the system responds when the sensors are touched.

So that you can figure out which sensor isn’t working properly. The parking sensor module or the wiring may be to blame if all of the sensors fail to work.

Checking the parking sensors with a smartphone

It is possible to find parking sensors that have a very low vibration and barely audible sound. Using the audio recorder on a smartphone as a diagnostic tool makes sense in this situation.

However, a basic voice recorder won’t do; you’ll also require an app that lets you create a visual representation of the incoming sound. In this scenario, the operating system and the program are of no importance.

Diagnostics are only possible when you’ve activated your app and placed your microphone near the parking sensor. 30 seconds should be enough time for the signal to be recorded and saved.

Before you can move on, you must hear the recording. Signals can be seen on the chart if there are any. A working sensor will also leave clicks in the recording.

This should be done in a peaceful area.

Checking the parking sensor with a multimeter

A multimeter is the most trustworthy tool for testing the parking sensors. Electrical resistance measurement mode must be selected on the tester, and sensors must be removed from a vehicle.

However, it is crucial to ensure that there is no break or short circuit in the sensor’s resistance value. The Pinout for three contact parking sensors is typically as follows. a plus for the first contact; a signal for the second contact; a minus for the third

More than 0.5 megohms of resistance is required in a functional sensor between plus and minus (the higher the better).

Resistance of about 2 40 kOhm should exist between the minus and signal contact points (depending on the sensor). The signal contact and the positive will both have a resistance of roughly 2 40 kOhm.

Additional diagnostics may be necessary if the measured resistance values are normal even though the parking sensors are defective.

Checking the parking sensors with a piezoelectric element

Piezoelectric sensors are used in Parktronic sensors. The voltage given to them causes them to vibrate and alter their shape. The opposite is also true.

It generates a voltage when the piezoelectric element moves. It’s a good idea to use this effect for testing. For this, you’ll need a parking sensor with a shielded wire and two LEDs that isn’t standard.

A counter-parallel circuit must be created by soldering these LEDs to the sensor’s output wire. This will allow the LEDs to alternate their polarity, resulting in a more dynamic light display.

Next, wash the sensor membrane and attach it to the sensor that is being tested on the car. This device’s LEDs will flash if it vibrates. Those parking sensors that don’t vibrate when you touch them can be tested using this method.

Checking the parking sensors with a scanner

To diagnose parking sensors in your automobile, you can alternatively utilize a computer program. You’ll need an electronic scanner to perform this. Using an ELM327 chip and a diagnostic app installed on your smartphone is the most convenient method. ELM Config is among the most popular.

The program allows you to read errors from various car systems, including parking sensors. PAM refers to the portion of the parking sensor that needs to be checked for issues. Once the error reading button has been clicked, the application will display the relevant information.