Modern vehicles have shifted from passive safety features to active safety and collision avoidance systems. All the information the car’s computer needs to avoid collisions and maneuver accordingly comes from an array of sensors splashed all around the vehicle.
Your park assist is one of the active collision avoidance and driver assistance systems in a modern car.
Come to think of it, park assist has to do many things to squeeze your car snuggly into a parking spot. It has to:
- Identify and map out the parking spot
- Calculate the perfect steering maneuvers to put you into the spot
- Know when to stop or go without colliding with obstacles and other cars
With the possibility of a fender bender so high, the park assist system will trigger an error message whenever all the sensors and actuators in its control fail a startup check.
The result is a Service Park Assist display on your dashboard. A couple of things could make the light pop up. The most common include:
An Issue With One or More Sensors
The auto parking system uses information from various sensors to determine the car’s position relative to the parking spot and surrounding objects.
Your sensors will vary depending on the vehicle and the complexity of the park assist. You could be looking at:
- A radar sensor
- Cameras (all cameras in your car)
- Other proximity sensors
If any of the above sensors malfunction or seem to be sending corrupted data to the park assist computer, the system will disengage and display the error message.
Problems could be as simple as something blocking one of the sensors to as complex as a damaged sensor or wiring.
Some vehicles can troubleshoot the system and tell you exactly which sensor is faulty once you plug in a diagnostic computer, while others will force you to run through the entire system.
ProTip: Something as simple as towing a trailer could block rear sensors causing the error message. Dirt and grime blocking other sensors could also cause the problem.
Some vehicles will display a different message if one of the sensors seems to be working fine but isn’t returning typical values compared to other sensors. The system could translate this as blocked but not damaged. You might get the ‘ Park Assist Blocked’ message.
ProTip: If you bumped into someone in what seemed to be a damage-free incidence and the front or rear bumper snapped back, you might still have damaged your sensors. The elastic bumper might recover from the impact, but your fragile sensors could be damaged and need replacement.
No Control Over One or More Park Assist Actuators
After gathering the information, the park assist computer needs precise control over the transmission (in an automatic,) the throttle, the brakes, and the steering wheel.
If there is a problem with one of these systems, park assist won’t work.
- Faulty brakes: The car won’t stop and will run into obstacles
- Faulty power steering: Park assist can’t manoeuvre the wheels to change directions and squeeze into a spot
- Faulty throttle: The car can’t accelerate or move
- Fault Transmission: If the park assist computer can’t shift between Drive and Reverse, it can’t park the vehicle independently
Luckily, you can note some of these problems long before park assist identifies them. For instance, you can notice a problem with your brakes, throttle response, or power steering in advance if you are a keen driver.
If you don’t, chances are your Check Park Assist light will be accompanied by error codes detectable by a decent scanner. The error codes will steer you to the problematic part of the system.
Damaged Wiring or Blown Fuses
All the sensors and actuators communicate with the control module electronically. As with any electronic part in the vehicle, wiring and fuses play a critical role in keeping the circuits open whilst preventing a fire in case of a short circuit.
The sensors or actuation will fail if you have a blown fuse, loose connections, or damaged wiring.
After using your scanner to identify culprits, you can use a multimeter to confirm if they have a live reference or 12V reading on their connections.
Also, confirm if terminals and plugs are fully connected. Loose connections can mess up your Park Assist sensors.
A Faulty Park Assist Module
Though very rare, the brains of your park assist system could go wrong. If this happens, the main ECU will default park assist to off and display the error message.
How to Reset The ‘Service Parking Assist’ Error Message
Different cars let you reset your park assist system at will. However, this might not be necessary since the Park Assist module and the main car computer periodically run functionality tests at the start and even when driving.
This ensures that it catches potential faults in the system long before you attempt to use park assist.
As such, manually resetting the system is not necessary. Fixing the problem and letting the system clear the error next time it runs scheduled checks should clear the error message.
You can still manually clear it by:
- Using an OBDII scanner with access to the Park Assist system
- Cutting power to the car to force a full system computer reset
- Following car model-specific reset procedure. Check your user manual for specific guides.
Warning: The Service Park Assist error message will pop right back up if you manually reset it without fixing the problem. Your priority should troubleshooting the entire system and replacing faulty sensors or servicing defective parts.
If you don’t want to and are comfortable parking your car, you could suppress the error message by turning park assist off. Some vehicles allow you to turn the entire system off and park as if it doesn’t exist.
How to Use Parking Assist
Parking assist systems vary from one car to another. They also differ from one model year to another. Some manufacturers have advanced autonomous systems, but others need a bit of assistance to dial in the parking spot.
The general approach is:
- Drive around a parking area until you find a parking slot
- Press a Parking Assist to engage the system
- The car uses cameras and sensors to assess the spot and display feedback on the infotainment screen
- You use adjustment buttons and guidelines on the screen to dial in the correct spot
- You press OK to initiate the parking as long as the car’s computer determines that the vehicle can fit into the slot
ProTip: In manual cars, the vehicle will prompt you what gear to shift into at what time. You will have to handle the throttle and the clutch, but it will cover the steering and braking.
You can still override the system by accelerating, braking, or turning the steering wheel at will.
Here is a look at how top vehicle manufacturers use automatic parking.
How to Use Active Parking Assist on a Mercedes Benz
The Mercedes Parktronic active parking assists to execute parallel parking moves. Here is how it works.
- Drive under 20 MPH to activate Parktronic with Active PArking assist. A blue P indicator light will pop up to indicate the system is looking for a slot.
- IF it identifies a place you can parallel park into, it will beep and highlight the spot. By this time, you will have passed the spot and will begin parking by reversing in.
- During the process, you will receive prompts from the system on if you should put the car on reverse or drive (always starts with reverse and hitting OK to initiate).
- You operate the brake and gas pedal, but the vehicle controls the steering wheel.
- Once the car is in place, it will display ‘ Finished’, and you can put it in park.
Pulling out of the space is as simple as putting on the correct blinker. The system will ask if you want to pull out. Hit OK and follow prompts to steer out of the spot.
ProTip: Grabbing the wheel at any time disables the system and gives you control of the vehicle.
How to Use Ford Enhanced Active Park Assist
Ford’s parking assist system has designated options for parallel parking and reverse perpendicular parking.
How to Parallel Park With Ford Active Park Assist
- Activate the system by pressing the Active Park Assist button labelled P with a steering wheel icon next to the shifter knob
- Use the turn signal to indicate which side you want to park
- Start driving forward slowly (Don’t exceed 22 MPH)
- The vehicle will start scanning for available spots and give you a spot found message when it identifies a place to park
- Once It finds the spot, the car will provide you with clear on-screen prompts on what gear to shift into, when to accelerate and when to brake. It will steer the car accordingly.
How to Reverse Perpendicular Park
The only difference between reverse perpendicular parking and parallel parking is how you activate the system. For reverse perpendicular parking, you have to DOUBLE PRESS the Active Park Assist button.
Auto Parking in a Tesla
If you haven’t disabled Autopark (if equipped), your Tesla will notice parallel park spots when driving under 15 MPH and perpendicular park spots when driving under 10 MPH.
A grep P icon pops up to the right or left of your instrument cluster, depending on where the parking slot is.
To use auto park:
- Press the brake pedal and stop the car, then shift into reverse. Keep your foot on the brake.
- Start Autopark will appear on your touchscreen. Tap on it and release the steering wheel and the brake pedal to initiate.
- The vehicle will Autopark taking charge of the shifting, acceleration and braking all along.
- Once done, it will notify you to put the car in park
- You can override at any time by braking and taking hold of the steering wheel
The above two examples show how activating and using parking assist has similarities and differences depending on the manufacturer and car model. Some systems are more advanced and hands-off, while others need extra input.
The bottom line is you have to remain vigilant and be ready to take over in case of a looming collision. You can’t sue a manufacturer for any accidents since they explicitly instruct you to stay vigilant and prepared to take over.
Some Situations When Park Assist Might Fail
Though parking assist works flawlessly in most scenarios, there are instances when it will ‘mess up’ and ‘panic’ when faced with insufficient data or unpredictable conditions. The most common include:
- When humans or animals throw curve balls by moving into the parking spot or running across unexpectedly
- Weather conditions like fog, heavy rain and snow interfere with sensor resolution
- There is a thin obstacle (like a post) that sensors can’t resolve
- There are soft sound-absorbing barriers that dampen radar (powder snow, for instance)
- A sloped space in the parking spot like a slopped embarkment
- Any electrical interference that messes up the sensors
- You are towing or have something obstructing sensors
Bottom Line
Parking assist is a great feature that makes one of the most mundane, complex, and necessary aspects of parking simpler. However, it still retains the possibility of slow speed accidents.
Keeping the system well serviced is paramount. Don’t use the system when the Service Parking Assist light pops up. Wait until you inspect the system and repair any faults.
Additionally, stay vigilant when the system is at work. Constantly scan the surroundings and be ready to brake when you feel the system is moving too close to an obstacle for your comfort.