Advanced driving assistance systems are getting increasingly common as standard equipment for mainstream and luxury brands alike. High-end BMW series such as the 5series and X5 are now equipped with the collection of driving assistance and collision advanced technologies which include forward collision warning with pedestrian detection, low speed automatic emergency braking, lane departure warning, blind-pot warning and rear cross-traffic warning.
Front collision warning system is a helpful feature that helps the drivers in avoiding collisions and stops the car automatically if necessary to prevent any damage from the crash or accident. It is a standard on all high-end BMW series but it can be adopted by the lower-end BMWs that upgrade the vehicle to the active driving assistant specification.
What does forward collision warning do?
Forward collision warning monitors for any obstacles ahead, as well as the pedestrians in the vehicle’s path. If the driver fails to brake or late to respond the situation, automatic emergency braking system engages to stop or slow down the BMW before impact. This feature is aimed at reducing the number of accidents on the road due to the driver’s inattention or negligence but this automatic braking works only at lower city speeds, for high-ways and freeways, the driver must respond to the potential collision situations.
How does BMW frontal collision warning work?
Forward collision warning system uses a short range radar sensor in the front bumper and a video camera to monitor the traffic in front of the vehicle, and can recognize the vehicles that are in the detection range of the sensor and video camera to alert the driver for any potential collision. It starts scanning the area in front of the vehicle as soon as the car is turned on.
When you are driving and if you approach another car in front of you too near, a read warning message will pop up on instrument cluster of your BMW to warn you for keeping a distance of your vehicle from the one in front of you and avoiding potential collision, if you do not pay attention and slow down, it will keep displaying the message and start to beep if you continue to accelerate. Auto emergency braking will be activated if you did not address the warning and distance between you and another car is narrowing or if the car in front of you has applied brakes. Your BMW will immediately start braking to avoid any collision and damage.
Can forward collision warning be turned off?
Though buying a car with advanced features and then turning those features off for any reasons other than safety is completely irrational. But if you want to disable or deactivate this amazing feature which is mostly active by default in all BMWs at speeds greater than 10 mph, you can deactivate the system by pressing the forward collision warning system button or by accessing your forward collision warning settings via your vehicle's information screen.
What does the warning error message mean?
The “frontal collision warning system inactive” error warning message simply means that the feature is no longer active and has stopped working properly. When this message appears it means that now your vehicle will neither detect possible collisions nor it will automatically apply brakes thus rendering your car into a difficult to drive and unsafe condition. Fixing any errors as soon as possible that come up on your dashboard is always recommended before they cause further damage to any other parts or prevent you from continuing the drive.
Why does this error appear?
This frontal collision system inactive message may appear on your BMW by either a software glitch that might have caused due to extreme weather conditions outside such as rain, fog, snow, dust etc and the radar sensor got confused with them. In that case to try enabling this feature again, stop your car; leave it off for 15-20 minutes as sometimes the extreme outside temperature can affect the sensors, so restarting the car after a while can reboot the system after which it should work fine. Or it may be a mechanical part failure such as radar sensor.
How to fix the error?
First of all, if the weather condition is bad, then leaving your car off and try restarting after the weather settles down or becomes better should work to remove this warning message.
But if it doesn’t; then reach to the front bumper of your car and check the sensor for any debris such as dirt, snow, fog that might have blocked the view of the road and clean it properly if found something.
It needs Replacement
If none of the above tricks work, then it’s definitely the mechanical part (the radar sensor) that has reached to its optimum life and failed to work anymore and needs a replacement. But before replacement, check for a few things to find out the reason of failure, if it is something else than life of a part.
Go to the front bumper of your car and remove it carefully, you will see a black box attached on bumper with clips. Gently unplug the wires and check if there is any moisture or water on the connectors or the sensor itself. If you find something moist then it is a tell tale sign that the sensor is damaged due to water or moisture and needs to be replaced.
Another thing to check for the failure is to inspect the sensor for any damage such as due to collision or short circuit. Smell the part and if it smells burnt then it surely has suffered a short circuit and needs to be replaced now.
Before replacing, try one cheaper trick more other than restarting and cleaning; and that is to check the software for its update and clearing any fault codes. If you have technological knowledge, with the help of diagnostic system scanner, you can attempt cleaning the fault codes as sometimes clearing the memory of the car helps in many cases.
Finally, if you did all the checks and the error still persists then you should consider replacing the radar sensor. Replacing can easily be done at home; all you need to know is just the correct part number that should match to the old one.
You can find a list of all compatible radar sensors with their car models at the end of this blog.