SRS MOT Failure

[aspguitars]

Hi! all,
I've just bought an old 2001 C220 Diesel. It drives really nice, but when I bought it the guy told me that it had an intermittent SRS light fault. I was told that it had just passed it's MOT in February. I'm still trying to fix the SRS fault, which apparently in my case is the Airbag Sensor Module.
However I've just read that as from the 20th of this month (March 13) SRS warning lights are now an MOT failure. It would appear that there are going to be thousands of cars off the road in the very near future, as in some cases it just won't be viable to repair them. I know that it's a common fault with BMW's. At least I've got a year to get mine done, but I feel sorry for anyone that has to get a new MOT.

MOT changes from 2012 | AA

 

[kth286]

how do you know it's the module ?

they are linked to the seat belts and is often simply a plug loose
within the circuit.

 

[richard]

> At least I've got a year to get mine done, but I feel sorry for anyone that has to get a new MOT.

I feel sorry for the people who get seriously injured in accidents where airbags would have protected them, and more so their families who have to live with an un-necessarily long-term ill (or dead) loved one. (and every other person who has to pay for the seriously expensive treatment to treat the injured driver/passenger, or even those who don't get treatment as a result of the money spent on treating them).

Get it fixed ! It will cost you the same now as it will 1 month before the MOT is due (possibly less, since you have time to plan). Don't guess whats wrong, get a good indie with Star Diagnosis to tell you which sensor is mis-reading.

Amusingly, it seems that they check the light works with ignition on, and goes out again, stops dodgy motor-traders removing the bulbs apparently.

Most likely a broken wire into a seat, or one of the sensors (such as passenger seat occupancy sensor)


Richard

 

[sjmaxwell]

Hi! all,
I've just bought an old 2001 C220 Diesel. It drives really nice, but when I bought it the guy told me that it had an intermittent SRS light fault. I was told that it had just passed it's MOT in February. I'm still trying to fix the SRS fault, which apparently in my case is the Airbag Sensor Module.
However I've just read that as from the 20th of this month (March 13) SRS warning lights are now an MOT failure. It would appear that there are going to be thousands of cars off the road in the very near future, as in some cases it just won't be viable to repair them. I know that it's a common fault with BMW's. At least I've got a year to get mine done, but I feel sorry for anyone that has to get a new MOT.

MOT changes from 2012 | AA

As Richard says get it fixed and dont bother with these emulator modules if its the seat occupancy mat - its a safety feature to have airbags and it may save a pasengers life or save your dashboard getting destroyed for no reason!

 

[aspguitars]

I had it checked at with a Star diagnostic so I'm pretty sure they know what they are doing. £481 excluding VAT. Apparently the light coming on doesn't necessarily mean that the airbags won't work. As mentioned, it could just be a seat belt. I've bought another sensor and just have to take it back to have the light reset.

 

[sjmaxwell]

I had it checked at with a Star diagnostic so I'm pretty sure they know what they are doing. £481 excluding VAT. Apparently the light coming on doesn't necessarily mean that the airbags won't work. As mentioned, it could just be a seat belt. I've bought another sensor and just have to take it back to have the light reset.

I don't think anyone questioned anyone's technical ability, it's just you didn't say that it was diagnosed at a dealer. The airbag may or may may not go off but I would hate to find out that it doesn't !!

 

[Howard]

Doesn't need to be diagnosed at a dealer.

In fact there are several independents on this very forum whose word I would take over that of a dealership.

 

[Blobsta]

I don't think anyone questioned anyone's technical ability, it's just you didn't say that it was diagnosed at a dealer. The airbag may or may may not go off but I would hate to find out that it doesn't !!

Did I buy a Sky HD box from you a couple of years ago??? You car/driveway and location looks very familiar

 

[richard]

I had it checked at with a Star diagnostic so I'm pretty sure they know what they are doing. £481 excluding VAT. Apparently the light coming on doesn't necessarily mean that the airbags won't work. As mentioned, it could just be a seat belt. I've bought another sensor and just have to take it back to have the light reset.

The light coming on means that some part of the system won't work in the way it is designed to protect passengers. You can not know which part of the system won't work, but the rest of the system *may* well work.

481+VAT sounds like the main control unit. If that is broken we really have no idea of what may and may not work. In the past, the only time I have seen main ECU failures is after an airbag trigger - i.e the outputs fail because of the current load triggering the airbag. I think they are designed this way though.

Now you've spent the money, please get it fixed - I'd like all our forum members in once piece

Richard

 

[sjmaxwell]

Doesn't need to be diagnosed at a dealer.

In fact there are several independents on this very forum whose word I would take over that of a dealership.

I was using the word "dealer" as anyone with access to STAR and yes there are some superb indies around

 

[sjmaxwell]

Did I buy a Sky HD box from you a couple of years ago??? You car/driveway and location looks very familiar

Possibly!

 

[markjay]

The front passenger sensor is there in order to ensure the passenger airbag does not deploy if no one is sitting there. It is mainly aimed at reducing accident repair bills.

Therefore the safety issue isn't so much with whether this feature is disabled or not, the issue is with the idea that a $2 cheap Chinese electronic components is connected to a critical safety system, and it's anyone's guess how it might affect the SRS' overall ability to protect the occupants in an accident.

 

[kth286]

I had it checked at with a Star diagnostic so I'm pretty sure they know what they are doing. £481 excluding VAT. Apparently the light coming on doesn't necessarily mean that the airbags won't work. As mentioned, it could just be a seat belt. I've bought another sensor and just have to take it back to have the light reset.

The light coming on means the bags will not inflate - the seat belts complete the circuit; and that is faulty, so nil circuit.

Hence MOT fail.

 

[Rory]

The light coming on means the bags will not inflate -

Is that MB specific? There's a picture of a car on PistonHeads with its airbags deployed and the light was on beforehand.


I have mixed feeling about this. One of my daughters has a car with 2 airbags. The other's car has 7 airbags. Shall I scrap the car with 2?

 

[Howard]

Yes ! Get rid of it immediately ! Don't you know it's not safe !

 

[Dieselman]

The front passenger sensor is there in order to ensure the passenger airbag does not deploy if no one is sitting there. It is mainly aimed at reducing accident repair bills.

Therefore the safety issue isn't so much with whether this feature is disabled or not, the issue is with the idea that a $2 cheap Chinese electronic components is connected to a critical safety system, and it's anyone's guess how it might affect the SRS' overall ability to protect the occupants in an accident.

It won't have any effect because the default is for the airbag to deploy.

As you correctly said, the sensor stops deployment to save the cost.

 

[markjay]

It won't have any effect because the default is for the airbag to deploy...

Correct - assuming the tiny electronic circuit does work as it should i.e. always tell the SRS control box that the seat is occupied.

My point is that I don't trust the device - what if it malfunctions and actually tells the SRS that the seat is unoccupied while in fact it is occupied - thus preventing the passenger airbag from deploying when it should.

I may worry too much, of course every electronic components might fail at any time, but this is my personal view on the issue.

 

[sjmaxwell]

I think I said it before in that you know you have an issue with the SRS light being on and I would hate to find out the hard way whether the air bag will deploy or not!

 

[Howard]

The emulator , while being cheap and Chinese ( as are most electronics ) is really just completing a circuit , as the seat occupancy pad does ( your weight completes the circuit by compressing it )

Not an awful lot to go wrong. Coupled with the fact the default setting in the event of failure is to deploy. If the box malfunctions , it will sense another problem and deploy in a crash.

Lets face it , if you have a crash that is enough to set the bags off , the car is probably going to be written off anyway. Before the keyboard warriors start searching for the couple of instances ever where the airbag deployed after hitting a mouse , I am talking in general terms for the ages of car we are discussing.

 

[Carrsey]

Shame airbags are a bit of a lotto whether they work or not. They do seem to be getting better on newer cars though..