Troubleshooting Car Parking Sensors
Have you experienced a situation when you were parking your car and instead of hearing a familiar beep, you heard a thud and accidentally damaged your car? If you were at a slow speed while reversing, the damage might be small, but a malfunctioning reverse parking sensor can be a serious problem. Parking sensors help you maneuver your vehicle securely without bumping it into a curb, wall, or any other parked vehicle. They are simple proximity sensors that sense an object in close range. Cars today are equipped with parking sensors located on the front and back of the vehicle and they provide audible and visual alerts to the driver in the cabin when one or more objects are detected. Car parking aid sensors are simple components that usually last a long time without any issues, but they may malfunction over time. If you notice anything off with your parking assist system, you must check the parking sensors before replacing them altogether.
What Is a Parking Sensor?
A parking sensor is a device that uses either electromagnetic or ultrasonic technology to detect obstacles while parking. These sensors are typically located on the front and rear bumpers of a vehicle and alert the driver of nearby objects by emitting acoustic pulses. The system then calculates the distance to the object and warns the driver with acoustic tones, with faster tones indicating closer proximity and a continuous tone indicating a minimal pre-defined distance. Some systems may also include visual aids, such as LED or LCD readouts to indicate object distance.
How Do Parking Sensors Work?
Parking sensors are devices that use either electromagnetic or ultrasonic technology to detect obstacles while parking. These sensors are typically located on the front and rear bumpers of a vehicle and alert the driver of nearby objects by emitting acoustic pulses. The system then calculates the distance to the object and warns the driver with acoustic tones, with faster tones indicating closer proximity and a continuous tone indicating a minimal pre-defined distance. Some systems may also include visual aids, such as LED or LCD readouts to indicate object distance.
Ultrasonic systems feature ultrasonic proximity detectors to measure the distances to nearby objects via sensors located in the front and/or rear bumper fascias or visually minimized within adjacent grills or recesses. The sensors emit acoustic pulses, with a control unit measuring the return interval of each reflected signal and calculating object distances. As an ultrasonic system relies on the reflection of sound waves, the system may not detect flat objects or objects insufficiently large to reflect sound (e.g., a narrow pole or a longitudinal object pointed directly at the vehicle or near an object). Objects with flat surfaces angled from the vertical may deflect return sound waves away from the sensors, hindering detection. Also, soft objects with strong sound absorption may have weaker detection, e.g. wool or moss.
Electromagnetic sensors rely on the vehicle moving slowly and smoothly towards the object to be avoided. Once an obstacle is detected, the sensor continues to signal the presence of the obstacle even if the vehicle momentarily stops. If the vehicle then resumes moving backward, the alarm signal becomes louder as the obstacle is approached. Electromagnetic parking sensors are often sold as not requiring any holes to be drilled, offering a unique design that discreetly mounts on the inner side of the bumper, preserving the ‘new factory look’ of your vehicle.
In this article:
1. How To Troubleshoot Car Parking Sensors?
- Clean Your Parking Sensors
- Check Your Parking Sensors Using An OBD Tool
- Check Parking Sensors Using A Multimeter
2. FAQs
1 How To Troubleshoot Car Parking Sensors?
Parking sensors usually last a long time and rarely fail. However, there might be times when parking sensor problems may come up, making driving difficult. Several factors contribute to the malfunctioning of a parking sensor like moisture, corrosion, and electrical faults. Parking sensors with an electronic fault usually throw up a fault code that can be identified easily using a diagnostic scan tool. However, a sensor may also malfunction due to other issues, like a cut or pinched wire, control module fault, or one or more failed sensors. The following methods will help you diagnose the parking sensor problem and restore its functionality.
Clean Your Parking Sensors
The first step is to identify if the parking sensors are dirty. Sometimes, too much dirt accumulation can affect the sensor’s ability to sense anything around your vehicle, causing it to malfunction. Clean the sensors, and while cleaning them, pop the sensors out and wipe the back with a clean rag. This will remove all the oil, dirt, and debris that can build up behind the parking sensors. A good way to prevent rust formation is to clean the metal housing of the sensors using WD40, which acts as a water dispersant and removes all the gunk from the sensors. Misaligned or loosely fitted parking sensors can also affect its operation. The parking sensors have a separate mounting inserted in the holes in the bumper. Ensure the sensors are fitted properly and carry out a visual inspection and check whether a sensor is loose or out of its position.
Check Your Parking Sensors Using An OBD Tool
An Onboard Diagnostic (OBD) Tool is an advanced gadget that allows access to the recorded data that helps in troubleshooting vehicle-related problems. Unlike old vehicles, cars today are equipped with various electronic systems that can fail and malfunction. When an error occurs in these systems, a trouble code is sent to the Electronic Control Unit (ECU) of the vehicle. These errors can be retrieved by a diagnostic tool. It helps identify the source of the problem and sensors which are faulty.
- To begin the diagnosis procedure, connect the OBD scanner through the diagnostic link connector (DLC) of your vehicle. Refer to the vehicle’s manual for the exact location of the DLC.
- Turn on the ignition of your vehicle.
- Select the vehicle’s make, model, year on the OBD tool and scroll to the Parking Aid Module (PAM) section. Select the option to start scanning.
- The scanner will read all the fault codes and will display which sensor is malfunctioning. It will indicate whether it’s the rear right outer sensor or rear left inner with error codes like errors B1B44, B1B46, etc.
- Once you have identified the faulty sensor, replace it with a new parking aid sensor.
- Clear fault memory from the OBD diagnostic tool to remove old errors and detach the tool from the vehicle.
Check Parking Sensors Using A Multimeter
If you don’t have access to a diagnostic tool, you can use a multimeter to check if the parking sensors are working fine. Follow the stepwise procedure to diagnose your faulty parking sensors easily.
- Go under the vehicle using creepers and identify the sensors located along the inner side of the car’s bumper.
- Insert the flat screwdriver between the sensor and the plastic that’s holding it and pry it. Gently tug the sensor outwards to pop it out.
- With the sensor detached from the bumper, disconnect the sensor from the socket.
- Identify the pins inside the sensor socket. Most parking sensors with 3 wires have three pins in a triangular formation with one pin at the top and two pins at the bottom. The top is negative and the bottom right pin is positive.
- Grab a multimeter and set the dial to resistance at 20k Ohms.
- Touch the red probe of the multimeter to the positive pin and the black probe to the negative pin of the parking sensor.
- The multimeter should give a reading of 500 ohms or above. If it doesn’t and reads below this range or doesn’t show any reading at all, the sensor is faulty and needs to be replaced.
- Repeat this procedure for all sensors and replace them if necessary.
Parking assist systems are equipped on almost all vehicles today and are even featured as standard equipment in many models. The parking sensors are located at the most vulnerable locations like bumpers, which makes the inspection and testing of these sensors very important. Drivers today rely a lot on these parking assist systems and if a sensor starts to malfunction, one might make a bad judgment while maneuvering the vehicle, leading to a damaged car bumper. The fastest way to resolve such an issue is to follow the simple troubleshooting methods mentioned in this guide so you can park your vehicle safely.
2 FAQs
How to reset parking sensors?
Here are some steps to reset parking sensors:
- Turn off the engine and locate the parking sensor control unit, which is typically near the front or rear bumper of the vehicle.
- Press and hold the “reset” button on the control unit for approximately five seconds.
- Start your vehicle and check if the parking sensors are now working correctly.
How to fix parking aid malfunction?
If you are experiencing a parking aid malfunction, there are a few things you can try to fix it. Here are some steps you can follow:
- Clean the sensors around your vehicle.
- Check the wiring of the parking aid system.
- Reset the parking sensor control unit.
How to test parking sensors?
To test parking sensors, you can follow these steps:
- Remove the sensor from the car and set your multimeter to measure electrical resistance mode.
- Locate the three-contact parking sensor (plus, signal, minus) and measure the resistance between “plus” and “minus” contacts. The resistance of a functional sensor between “plus” and “minus” exceeds 0.5 MΩ, but there should be a 2–40 kΩ resistance between each of the two and the signal contact.
- If the value on either test changes dramatically, the parking sensor is damaged and must be replaced.
How to clean parking sensors?
Cleaning parking sensors is a simple task that can be done with a few basic steps. Here’s how you can clean your parking sensors:
- Fill a bowl or bucket with warm water and add a small amount of car shampoo.
- Immerse a soft microfiber cloth in the water solution and rinse it thoroughly.
- Wipe the dirt off the sensors gently with the microfiber cloth. Use the tip of your finger in a circular motion to cover all areas.
Where are park assist sensors located?
The location of park assist sensors varies by vehicle, but they are typically located on the front and rear bumpers of the vehicle. For example, Chevrolet’s Front and Rear Park Assist system uses multiple ultrasonic sensors located on the front and rear bumpers of the vehicle. The sensors emit acoustic pulses to detect nearby objects while parking.
What causes parking sensors to fail?
There are several reasons why parking sensors may malfunction or stop working altogether. Some of the most common causes include:
- Dirt and debris: Accumulated dirt, dust, or debris on the sensor surface can obstruct its functioning and lead to false readings or no readings at all.
- Moisture and corrosion: Exposure to moisture can cause corrosion in the sensor’s metal housing or electrical connections, resulting in malfunctions.
- Electrical faults: Faulty wiring, damaged connectors, or problems with the control module can disrupt the proper functioning of parking sensors.
- Physical damage: Impacts or collisions can damage the sensors or their housing, rendering them ineffective.
