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child seat recogntion sensor mat connector w211 w220

Child Seat Occupancy Recognition Sensor Problems and Solutions


srs warning lightThe airbag warning SRS light could come on due to a defective Child Seat Occupancy Recognition Sensor which is installed in the passenger seat.

If you had an auto mechanic diagnose the car or if you scan the airbag module yourself using Launch Creader VII Diagnostic Scanner you will find one of the following errors:

  • Child seat recognition seat sensor
  • Seat occupied recognition control unit
  • Passenger seat occupancy sensor

This article will clarify the Airbag / SRS light problems due to defective child seat recognition sensor on the passenger seat. In this article, we discuss what the child recognition sensor is, and the pros and cons of disabling the light using a child recognition emulators.

warningThis article is for information purpose only and it may not be complete or completely accurate. Do not disable safety features on your car. We recommend that you replace the defective sensor instead of disabling the child seat recognition feature or installing an emulator.

What is the Automatic Child Seat Recognition Sensor (AKSE) ?

On the passenger seat of Mercedes-Benz cars, a weight sensor is installed known as a child seat recognition sensor. This sensor is found not only on Mercedes-Benz E-Class W211 or S-Class W220 but also on other models such as CLS, CLK-Class, C-Class, ML-Class. Most Mercedes-Benz models since 2000 have the child seat recognition sensor installed. This is a great safety feature, but it does fail quite frequently.

When a child sits on the front passenger seat, this is detected by the child seat recognition sensor. And if you were to get in an accident with the child on the front passenger seat, the passenger airbags WILL NOT deploy. That’s because if the airbags deploy and a child is seating in the front, they can cause injuries to the child.


Disable child seat recognition sensor

The correct method to fix this problem is to replace the child recognition weight sensor mat. Many Mercedes-Benz owners end up disabling the child seat recognition sensor instead of replacing it. The two common methods that you will find Mercedes-Benz owners eliminate the SRS warning light is by either installing an emulator or re-programing the Air Bag control unit. Both of these two methods achieve the same thing by eliminating the child seat recognition function.

When the child seat recognition sensor is disabled, and you were to get into an accident, both driver and passenger airbags will deploy. This is not a problem if no-one is sitting on the passenger side, but it is a problem if a child is on the front. Front airbags deploying on children can cause serious injuries.

So owners who disable the child seat recognition sensor need to be 100% sure no child sits on the front passenger seat.

How is SRS disabled via Mercedes-Benz Star Diagnostic Programing

Auto repair shops that have a Mercedes-Benz Star Diagnostic Scanner have been reported to disable the child seat recognition sensor using the scanner. Basically, they access the Airbag Control Module then go to Contro Unit Adaptations and program the car so that there is no Seat Occupied Recognition Sensor by disabling the AKSE/SBE and switching it to not present.

Notice that a Mercedes-Benz authorized dealership will most likely not disable the child recognition sensor due to safety concerns. You should consider replacing the sensor with a new one instead of disabling it. It is up to you the owner on which route you go, you are responsible for what you do with your car of course, regardless of what anyone  recommends. Keep in mind that disabling a safety feature on your car may violate federal law.

If you are worried that the child recognition sensor has been disabled on your car, there is one easy way to check. Look under the passenger seat to see if the Passenger Seat Occupancy sensor has been unplugged. If someone has disabled the sensor via programming they would also have to unplug the sensor in order to erase the SRS light.

Check under the passenger to make sure that the child seat recognition seat sensor is not unplugged. Here is a picture of the connector that you will find unplugged if AKSE is disabled.child seat recogntion sensor mat connector w211 w220

Airbag Light Reset Seat Occupancy Sensor Emulator

child seat emulator simulator for mercedes benzIf you do a quick search on Amazon, for example, you find several  listings for Seat Occupancy Occupation Sensor SRS Emulator. Owners may install an emulator which will bypass the child seat recognition feature and just erase the fault code via the OBD-II port under the dashboard. While this method will also get the SRS light erased keep in mind that it will disable the child recognition feature on your front passenger seat.

The emulator generates a signal to make the airbag control module think that a person is sitting on the front passenger seat at all times. Meaning the front passenger seat appears as it is “allways ocupited” even if there is no one sitting on that seat. Therefore the airbags will deploy even if a child seat is present on the front seat.

While this method will also get the SRS light erased, in the end it still disables the child recognition safety feature. Instead of programming the car to not recognize the child occupancy sensor, you install an emulator that tells the car there is a passenger on the front at all times. In return the car thinks the seat sensor is working and there is an adult sitting on it all the time. Therefore, in case of an accident driver and passenger airbags will deploy. The important thing to understand is that just like disabling the ASKE, installing a simulator/emulator also disables the child seat recognition feature.

If a emulator is installed a diagnostic scanner such as the Launch Creader VII is used to clear the fault codes.

Replacing the child seat occupancy recognition sensor.

Replacing the child seat occupancy recognition sensor is the best solution to get rid of the SRS warning light. It may be more expensive and labor intensive than disabling the feature. On the other hand you will solve the problem the right way. Replacing the child seat recognition mat is possible but requires the seat to be removed. Here is a Mercedes-Benz owner that replaced his on a E-Class.

You can find new or used Mercedes-Benz Child Seat Recognition mat on eBay and save money.

How to Reset the Airbag SRS Light yourself

Resetting the airbag srs light is very simply if you have a diagonsitc scanner that works on Mercedes-Benz airbag control unit. One scanner that we recommend that will read, erase and clear airbag srs fault codes is the Launch Creader diagnostic scanner.

Keep in mind that you can NOT erase the airbag SRS light unless you fix the problem first. Don’t assume the problem is always the child seat recognition sensor. Use the scanner mentioned above to read the fault codes first. This will give you a very good idea on what is causing the SRS light to illuminte. Watch the video below to learn how easy it is to use a diagnositc scaner to troubleshoot the SRS light.

One of the best scanners that you can use to troubleshot your Mercedes-Benz is the Launch Creader Diagnostic Scanner which you can find on Amazon. It is affordable for Mercedes-Benz owners to do troubleshooting on their cars. Not does it work on Mercedes-Benz cars, but it also works on European, Asian and Domestic cars.

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