Mercedes Benz Lane keeping assistant is very similar to blind spot system assist and utilizes very identical technology and the way it works.

Keep reading to find out what causes lane keeping assist inoperative malfunction, how to fix at home without spending a fortune on it!

How lane assist works

Active lane assist works through a camera that is installed on the top of the windscreen together with blind spot assist radar sensors on the rear of the car. So that means in case you are trying to leave your lane it won't let you to departure that lane, will start to vibrate your steerting wheel, brake left or right side wheels and ofcourse give a warning on the mirrors, that it is not safe and it could end up in collision with other vehicle. The camera’s function is to detect the boundary lines of the lane. It works in conjunction with radar sensors. The lane assist radar's job is to check the areas to the side and rear of the car. It also registers the appropriate driving information.

The speed at which the system is activated is 60 kilometres per hour or 40 miles per hour, whichever is relevant.

Choose your preferred setting

In order to activate the lane-keeping assistant, you must first use the buttons on the steering wheel. You then navigate your way through to the assistance menu on the car’s onboard computer. Once there, you are then given a choice of selecting which option you prefer - the standard or the adaptive settings under lane-keeping assist.

If you opt for the standard-setting and you accidentally drive across a lane marking, you will feel a short vibration in your steering wheel to alert you. If, however, you have activated the turn signals, the warning is temporarily disabled. This disabling also applies if a driving safety system, such as ABS, for example, is in force.

If you choose the adaptive setting, you do not get the vibration warning when you are accelerating quickly or braking hard. This also applies if you are in the process of actively steering the vehicle or if you are cutting the corner on a sharp bend.

Overrides

If you ignore the warning vibration, a course-correcting brake application will automatically come into play. You will see a message in your multi-function display and your course will be corrected back to the centre of the lane. The brake application can be overridden at any time by steering slightly in the opposite direction. This also applies if you are signalling, significantly accelerating or braking hard.

To avoid unnecessary interventions from your lane assist radar, the control module takes certain driving conditions into account but will warn you what is happening.

Common causes of lane-keeping assist inoperative warning messages

From time to time you may get a Mercedes-Benz active lane-keeping assist inoperable warning message on your multi-function display. The most common causes of stopping mercede benz lane assist working is certain external circumstances. These include:

  • In heavy rain
  • When snow is around
  • When the car is iced up
  • In foggy conditions
  • When visibility is poor
  • When lane markings are poor or non-existent
  • Faulty radar sensor

If still this error persists, that could mean you need to replace control radar sensors. Lane change sensors are located at the rear, under left and right side bumper.

Before doing any radar replacement, check carefully for any moisture or water damage as it is electronic part it's not supposed to get any moisture, this is the most common reason why it fails, the second reason could be just part's life-time.

Every single part has it's life-time, so once it is reached it could end up with short circuit and part becomes faulty.

Sometimes electronic gadgetry simply plays up. This can often be resolved simply by stopping the car, turning the ignition off, waiting for 5 minutes to let on-board computer restart all the calculations and restarting your car.

Autoliv ASP inc. from Sweden is the main supplier for mercedes benz cars of radar sensors.

Mercedes-Benz cars having lane keeping assist:

  • C-class W205 Saloon Sedan
  • C-class S205 Estate Wagon
  • C-class A205 Convertible Cabriolet
  • C-class C205 Coupe
  • C220 C250 C300 C350e C400 C45 C63 AMG 4Matic BlueTEC
  • E-Class W212 S212 A207 C207 Facelift
  • GLC-class X253 Hatchback
  • GLC-class C253 Coupe GLC300
  • ML W166 GL 450 ML350 GLE350
  • GL X166
  • CLS W218 C218 CLS63S AMG
  • S-class W222 Saloon Sedan
  • S-Class A217 Convertible Cabriolet
  • S-Class C217 Coupe
  • S Class S300 BlueTec S320 S350 S400 Hybrid S500 S550 S65 S63 AMG 4Matic

Lane keeping assist sensor part,  software and hardware numbers:

  • ZB A000 905 88 02
  • ZB A0009058802
  • SW A0009026713
  • HW A0009017901
  • HW: 12/04.01
  • SW: 12/36.00

If the inoperable message persists and none of the above external conditions is prevalent, you can talk to us here at Xenons4U or complete the “contact us” form on our website.