SRS Light MOT Failure?

[Vito71]

Hi all - first post here...but I've done a lot of reading.

We have a 2009 Vito 110 CDI and the SRS light has been on the dash for about 3 years ...not that long after we purchased it second hand! We took it to our local garage and they explained that it was a seat belt restraint warning light, but either weren't that bothered if we weren't, or didn't bother fixing it - I cant remember the outcome as it was a few years ago and we just wanted reassurance that it was nothing serious.

Roll forward to now and the light remains on - no other problems...BUT today it failed its MOT because of that.

I'm guessing it is a failure ,...but we have never failed because of this before.

What is the quickest/easiest fix please? Garage have suggested that they will see if they can find a replacement part, but actually haven't taken anything part yet.

Any advice please?

 

[KennyN]

If the SRS light is on then it is a failure, no question so how it passed previous tests is a mystery.

Loads of potential causes of this fault , too many to just start replacing random parts so the fault codes will need read to find the source of the problem.

Either get a decent code reader or take it to someone to read them for you.

What part was the garage going to replace ?

K

 

[Vito71]

Hi Kenny - thank you for the reply...I'm not actually sure....but something to do with the seatbelt I think! I will find out more tomorrow..

Appreciate your advice

 

[markjay]

The most common (though not the only) cause for SRS faults on MB cars is a failed Front Passenger Seat Occupancy sensor mat, cost ~300 to fix, about half of it is the part the other half is labour.

Of course, the codes will need to be read by STAR (or iCarsoft/Carly) to confirm.

 

[baxlin]

The most common (though not the only) cause for SRS faults on MB cars is a failed Front Passenger Seat Occupancy sensor mat, cost ~300 to fix, about half of it is the part the other half is labour.

Of course, the codes will need to be read by STAR (or iCarsoft/Carly) to confirm.

On another marque, a common cause is simply one of the the under-seat connections becoming loose or corroded. Refitting - or replacing with soldered joints - solved the problem.

But doesn’t SRS also relate to airbags? (If a 2009 Vito has airbags?) I would be worried they wouldn’t deploy if the warning light was on. As well as obviously being dangerous, it could well void insurance.

Edit: just googling this, the consensus of various articles seems to be that it’s not safe to drive with the SRS light on, which would back up the MOT failure. Can I be nosy, and ask Vito71, how was the defect categorised on the fail certificate?

 

[zipdip]

Best get it fixed,but make sure the garage uses a star diagnostics on it to make certain the thing going wrong is fixed as it will be a couple of hundred pounds to fix.

 

[Vito71]

The most common (though not the only) cause for SRS faults on MB cars is a failed Front Passenger Seat Occupancy sensor mat, cost ~300 to fix, about half of it is the part the other half is labour.

Of course, the codes will need to be read by STAR (or iCarsoft/Carly) to confirm.

wow thats an expensive fix! Bearing in mind we just need the light to go out to pass the MOT, is there any way round this?

 

[markjay]

wow thats an expensive fix! Bearing in mind we just need the light to go out to pass the MOT, is there any way round this?

Firstly, you need to scan the car for fault codes using a proper scanner (STAR preferably), to be sure which component has failed.

Then, if it is indeed confirmed to be the mat sensor, then there are cheap Chinese emulators on eBay that trick the SRS system into thinking that the seat is fine and occupied. It will extinguish the warning light, but I can't recommend it, because I have no idea if it's safe to use, and no idea what would be the insurance implications. Personally, I wouldn't fit one of those to any car I owned, or otherwise temper with any safety system on the car.

 

[whitenemesis]

Personally, I would fit one if those to any car I own.

Presumably you meant wouldn't fit one?

 

[markjay]

Presumably you meant wouldn't fit one?

Haha, thanks, now corrected

 

[zipdip]

Yes the front seat occupancy sensor on MB is one it could be,on VW cars it is the connection under the the front seat that normally shows up the SRS light,I suspect that if you passed a couple of MOT's with it on,then this time you took it to another test station,I have know centres ignore the light,also ignore number plates with the spacing wrong,but as I said get it on a star and find out what is causing the SRS then take your decision as to repair or hide it.

 

[baxlin]

wow thats an expensive fix! Bearing in mind we just need the light to go out to pass the MOT, is there any way round this?

The thing is, SRS covers both belts and airbags. Do you want to risk it not just being a seat belt sensor? Sorry, but I know I wouldn’t.

 

[Vito71]

On another marque, a common cause is simply one of the the under-seat connections becoming loose or corroded. Refitting - or replacing with soldered joints - solved the problem.

But doesn’t SRS also relate to airbags? (If a 2009 Vito has airbags?) I would be worried they wouldn’t deploy if the warning light was on. As well as obviously being dangerous, it could well void insurance.

Edit: just googling this, the consensus of various articles seems to be that it’s not safe to drive with the SRS light on, which would back up the MOT failure. Can I be nosy, and ask Vito71, how was the defect categorised on the fail certificate?

Hi I actually haven't been given the fail certificate... but I will find out when I go back. the garage have ordered a new part and plan to do the repair next week.

 

[baxlin]

Hope you get it sorted.

 

[Brundle13]

OMG - this is EXACTLY the same problem I currently have! Failed my MOT this morning at Kwik Fit because SRS light is on. I now have no MOT. as it's run out. Had no idea a lit SRS was a fail I'd assumed the light being on was connected to a Mercedes recall I got to replace my drivers airbag (which I can't get done until 8th October due to the part not being in stock at the MB garage). Kwik Fit did run their scanner on it but it came up with no fault found so couldn't reset the light, so MB garage now having to do diagnostic tests next week when it's in for the airbag replacement. Sounds like this could be pricy though

 

[wongl]

OMG - this is EXACTLY the same problem I currently have! Failed my MOT this morning at Kwik Fit because SRS light is on. I now have no MOT. as it's run out. Had no idea a lit SRS was a fail I'd assumed the light being on was connected to a Mercedes recall I got to replace my drivers airbag (which I can't get done until 8th October due to the part not being in stock at the MB garage). Kwik Fit did run their scanner on it but it came up with no fault found so couldn't reset the light, so MB garage now having to do diagnostic tests next week when it's in for the airbag replacement. Sounds like this could be pricy though

I had a problem with the SRS light on (solid not flashing) with no error codes to clear - turns out that the SRS module was in unlocked state and simply required relocking using STAR!

Good luck with yours and hope that you report back here what was the fault diagnosed by MB and the fix required to put it right.

 

[GP801]

We have the same issue with our R171 SLK. SRS light comes on and off at random times. As its due its MOT soon Jack at PCS put it on Star and yes its the passenger seat occupancy sensor that is faulty. Unfortunately the sensor is not available as a separate part. A new seat base is required! The £300 quoted in an earlier post sounds an absolute bargain compared to the cost of a new seat base. I did think about using an emulator but thought it would possibly interfere with the airbags etc. Its booked in at PCS tomorrow for service, MOT and the new seat base. I will let you know how it goes. Cant complain too much as its the only non service part that its needed since it was new in 2005.

 

[Dichtung]

I`ve experienced this problem twice - both W210s . An electric wire connects the sensor in the seat squab to a junction box fastened to the seat chassis.
i am not an electronic boffin, but I figured out that this wire is subject to continuous minor flexing when the seat is occupied and the car is moving, more so when the passenger enters and leaves.
With this in mind I found breaks in this wire in both cases near to where the wire joins the junction box.
With the seat totally out, a simple soldering job fixed the problem for good.

IIRC , replacing the sensor would be a nightmare.

I presume this seat sensor malarky is to save the dash being wrecked by an airbag explosion if the seat is unoccupied and the vehicle is involved in a shunt. If that`s true, a bit OTT?
Hope this helps someone.

 

[BTB 500]

I presume this seat sensor malarky is to save the dash being wrecked by an airbag explosion if the seat is unoccupied and the vehicle is involved in a shunt. If that`s true, a bit OTT?

Not just the dash ... seatbelt pretensioner, seat (side airbags), headlining/pillar panels (curtain airbags), etc. I'd guess that replacing these unnecessarily if the passenger seat wasn't occupied could write off older vehicles, regardless of other damage sustained?

 

[GP801]

Well that didn't go to plan! The new seat base did not have a sensor! No stock in UK or Germany so at present no idea when one will turn up. You really couldn't make it up. To add insult to injury the rear subframe is toast. So bad that Ollie would not let me drive it away. It could have let go at any time. Its only done 50,000 miles. The rest of the underneath is pristine. On Monday its being taken by truck to MB Gatwick for hopefully a goodwill repair from MB. Fingers crossed.