Mercedes-Benz vehicles including E, C, S, CLS, ML, GL, R, G Class, may display the following warning messages on the instrument cluster.
To temporarily remove the warning message, press the reset button on the steering wheel or instrument cluster. In many cases, the error message comes back again when the passenger seat is occupied/vacated or when the vehicle is restarted.
Other possible symptoms related to this problem include:
This message may also come up if there is a Mercedes-Benz child seat on the front passenger side. If you have an adult or don't have any passengers present but are getting any of these messages, it means a malfunction has been detected by the Weight Sensing System , also known as WSS or N2/13 control module. The main input for the WSS module is the four weight sensing sensors located in the passenger seats known as B48/11, B48/12, B48/13 and B48/14.
Passenger seat weight sensor detects the weight of the person on that seat. This is important because if the WSS detects low weight, in other words, a child on the passenger seat, it will not deploy the passenger airbags because they can cause injury to the child.
To fix this problem, the first thing that you need to do is check if there are any objects below the passenger seat that may be obstructing the movement of the seat. Move the passenger seat all the way FORWARD and UP and check for objects including in the seat tracks.
Once you remove any objects below the passenger seat, cycle the ignition on and wait for at least 1 minute. No passenger should be seated on the passenger seat.
Turn off the ignition and turn it back on. Hopefully, the error message is gone. If the error message remains, move to the next step.
If the problem remains the next step is to perform WSS (Weight Sensing Sensor) calibration. To calibrate Mercedes weight sensor module, you will need the official Star Diagnostic Scanner used by the dealer or a Professional Diagnostic Scanner used by auto mechanics. You can NOT perform WSS calibration with scanners such as iCarsoft MB II or Launch Creader.
Various weights were used to simulate a child and an adult sitting on the passenger seat. First, you calibrate the seat with no weights on. Next, you calibrate the passenger weight sensors with 17 kg and 44 kg.
A bag of the concrete mix was used to simulate the 44kg weight.
The WSS calibration may vary slightly depending on the scanner. Here are the general steps and some important tips to keep in mind when calibrating the passenger weight sensor on Mercedes-Benz cars.
Below you will find general instruction on how to perform Mercedes WSS Calibration.
Here is another example on how to perform Mercedes passenger weight sensor calibration using Autoland ISCAN II professional scanner.
During passenger weight sensor calibration you may get the following errors.
9A02 Zero point setting not Completed
That's it. In summary. First, remove any objects from under or behind the passenger seat first. Hopefully, that will reset the error message. If not, Mercedes passenger weight sensor may go out of sync and will need recalibration. Take your car to a mechanic (who specializes in Mercedes cars) or the dealer to perform passenger weight sensor calibration. The average cost for this procedure ranges from $150 to $250. The calibration procedure takes approximately 30 minutes and any mechanic with the right scanner should be able to perform this procedure.