The advent of the autonomous car has highlighted the fundamental importance of high-performance sensors. However, we have long been committed to providing our customers with effective – and reliable – sensors. So, whether you’re looking for sensors for the engine and transmission, or for comfort and safety – not forgetting emissions and e-mobility – take a look at our product ranges.
The role of these sensors is to help the driver park their vehicle by alerting them to the immediate proximity of a possible obstacle. For this purpose, they use ultrasonic technology, and although they have long been referred to as “reversing sensors”, this is no longer the case, since they are increasingly also present at the front of the vehicle.
In concrete terms, when these sensors detect an obstacle, the driver receives a visual and/or acoustic signal, which becomes more and more pronounced as the distance is reduced. It logically follows that the more sensors are installed, the more accurate the measurement is.
In the passenger compartment, as mentioned earlier, the driver can be alerted by acoustic signals alone; this is especially the case on older vehicles. Then, manufacturers moved on to LED indicators and, more recently, graphic displays on the multimedia system screen – and if not, simply a coupling of the information from these sensors with the video display of a parking assistance camera.
The frequency of the signal increases as the distance to the obstacle decreases, and shifts from a distinct “beep” to a continuous sound at about 25 centimetres.
ULTRASONIC SENSOR TECHNOLOGY
The sensor uses ultrasonic technology, which works as follows: the sensor emits a signal, which reflected by a nearby object, and this return pulse is interpreted to measure the distance between the sensor and the object in question.
In a vehicle, the system consists not only of sensors, but also of a control unit, a warning device (acoustic, and often visual), and a module called a “disconnector”. This activates the system when the vehicle is in reverse – in fact, it is extremely rare for parking sensors, even those at the front of the vehicle, to be activated without the driver first initiating a reversing manoeuvre.
SYMPTOMS
The following symptoms are frequently associated with the failure of a parking sensor:
DIAGNOSTIC PROCEDURE
First and foremost, you need to visually inspect the parking sensor(s) to determine the presence of a fault. It is therefore strongly recommended to first check whether the sensor(s) has/have not received a blow (presence of traces on the sensor body) and whether it/they is/are still located in the predefined position within the bumper.
As a second step, you can conduct a test by bringing an object (such as a metal plate) close to the parking sensor(s) after engaging the reverse gear. It is necessary to ensure that the signal varies correctly with the movement of the object.
The only other possible procedure – which does not involve the complete removal of the bumper – is to have the vehicle diagnosed through the OBD socket. In fact, the parking sensors are monitored by the ECU, which will record any faults in its memory.
If the previous tests are not conclusive, the parking sensor(s) in your vehicle must be replaced.
CAUSES OF FAILURE
It is possible that a parking sensor no longer functions due to:
INSTALLATION INSTRUCTIONS
To ensure a quick and efficient installation, you must refer to the following instructions:
INSTALLATION TIPS
As the parking sensor is essential for detecting the vehicle’s environment, it is important to follow a certain number of recommendations when replacing it:
PREVENTIVE INFORMATION
The above items are provided for information purposes only. They do not replace the advice of a qualified technician or mechanic. We strongly recommend that you ask a professional if you have any doubts about the operations to be carried out. If you do not, we will not be responsible for any damage to your vehicle.
When a parking sensor is faulty, you may no longer hear a “beep” when you put your car in reverse gear; or conversely, this noise may sound without you having tried to park. Sometimes the signal (acoustic and/or visual) no longer corresponds to reality; i.e., you are much closer to the obstacle, or on the contrary, further away, than the system indicated. Finally, on certain vehicles, a specific indicator will light up on the dashboard.
To determine whether your parking sensor is actually faulty, you can start with a visual inspection to ensure that none of the sensors in question have suffered an impact and that they are all in their predefined positions within the bumper. Secondly, you can bring a large enough object – such as a metal plate – up to your bumper, and when the car is in reverse gear, you move the object closer and then further away to check whether or not the signal is changing correctly.
The only other possible procedure – which does not involve the complete removal of the bumper – is to have your vehicle diagnosed through the OBD socket. In fact, the parking sensors are monitored by the ECU, which will record any faults in its memory.
Automotive sensors are obviously designed to withstand particularly harsh environments, but they are not indestructible. For example, if your parking sensor is poorly anchored in the bumper, there is a risk of water ingress, and this moisture can completely distort the results of the ultrasonic feedback analysis. In addition, an impact can disable one (or more) of the parking sensors, as can a short circuit. It is also possible that the signal transmitter has failed.
To replace your parking sensor, first remove the bumper, and any other body parts required upstream (such as rear lights, in most cases). Then disconnect the electrical connector and carefully release the locking tabs. The sensor to be replaced can now be removed from its holder. If necessary, the new sensor’s membrane should then be painted on the front and sides, using a stencil to avoid painting outside this area. After drying, you can reinstall the new sensor, snap it into place and reconnect its connectors. Finally, you will just have to refit all the body parts, including of course the bumper
As a sensor specialist, we recommend that you apply the following recommendations to extend your parking sensor’s durability:
