SRS Warning indicator B Class 2013 W246

[AndrewBClass]

SRS Warning indicator B Class 2013 W246. My SRS warning light is coming on. What is the most likely cause of this? Are there any easy to try fixes before I escalate to a technician? Thanks.

 

[markjay]

Welcome.

Most likely: search for Front Passenger Seat Occupancy Sensor Mat.

But it need to go on STAR diagnostic to confirm.

The best you can do DIY is check the electric connector under the front passenger seat (with ignition off and key removed(.

 

[Jobsworth]

Belt stalk buckle has a switch in it. Very common on the B for some reason. Need a diagnostic to be sure

 

[AndrewBClass]

Thanks for your help. Will the diagnostic localise the fault to the belt stalk buckle? Also what exactly is the sensor mat, is it the spaghetti of wires under the seat? Thanks again. Andrew

 

[markjay]

Thanks for your help. Will the diagnostic localise the fault to the belt stalk buckle? Also what exactly is the sensor mat, is it the spaghetti of wires under the seat? Thanks again. Andrew

While a diagnostic scan will read the fault codes, it may not always be obvious from the results what the actual problem is.

Having said that, in my experience, when it comes to SRS faults, the diagnostic scan usually does pinpoint the culprit.

The Front Passenger Seat Occupancy Sensor is a mat of sensors inside the passenger seat. It's aim is to detect the presence of a person (the sensors are sensitive to pressure), and arm the passenger airbag. This prevents the passenger airbag from deploying in the event of a crash when the passenger seat is unoccupied. You can buy a cheapo Chinese emulator on eBay instead of replacing a faulty sensor mat, but I advise against it.

It's item no. 40 in the drawing below:

But, again, the faulty component needs to be confirmed by STAR diagnostic first.

 

[AndrewBClass]

While a diagnostic scan will read the fault codes, it may not always be obvious from the results what the actual problem is.

Having said that, in my experience, when it comes to SRS faults, the diagnostic scan usually does pinpoint the culprit.

The Front Passenger Seat Occupancy Sensor is a mat of sensors inside the passenger seat. It's aim is to detect the presence of a person (the sensors are sensitive to pressure), and arm the passenger airbag. This prevents the passenger airbag from deploying in the event of a crash when the passenger seat is unoccupied. You can buy a cheapo Chinese emulator on eBay instead of replacing a faulty sensor mat, but I advise against it.

It's item no. 40 in the drawing below:

But, again, the faulty component needs to be confirmed by STAR diagnostic first.

Thanks. So helpful.

 

[colinallcars]

Thanks. So helpful.

What message are you getting? On my B Class it was the driver’s seat belt buckle as mentioned above. Easy to replace although you’ll need to use mole grips to undo the bolt as there isn’t room for a socket. You’ll find the part number written on it, search on eBay. They’re common to a number of models so readily available.

 

[AndrewBClass]

Welcome.

Most likely: search for Front Passenger Seat Occupancy Sensor Mat.

But it need to go on STAR diagnostic to confirm.

The best you can do DIY is check the electric connector under the front passenger seat (with ignition off and key removed(.

Thanks, Andrew