Mot problems..

[tom2019]

Hi

I'm having some trouble with the airbag light on my car. If i wire the airbag light to a light that goes off after the ignition turn will they be able to tell?

[E65Ross]

tom2019 said:

Hi

I'm having some trouble with the airbag light on my car. If i wire the airbag light to a light that goes off after the ignition turn will they be able to tell?

as long as the light lights up when the ignition goes on and then goes off again then it will pass as far as I'm aware.

[HumbleJim]

What's the car?

[V8forweekends]

Unlikely (they will be able to tell) unless you leave wires sticking out. I would be more worried about mucking about with airbag wiring and the effects if I had a crash. Call me old fashioned, but I'd quite like the airbag to do its job.

[tom2019]

So they won't be able to tell other than the light that the airbag isn't working. They won't hook my car up to a computer?

[tom2019]

HumbleJim said:

What's the car?

Fiesta mk6

[V8forweekends]

tom2019 said:

So they won't be able to tell other than the light that the airbag isn't working. They won't hook my car up to a computer?

MOT won't hook your car up to a computer, no.

[Krikkit]

Diagnostic connection isn't part of the MOT, no.

What car are we talking about here? I'd be wary of messing with the wiring of a still-connected airbag system, even diagnostic indicators.

[r11co]

More details required.

What exactly is the 'problem' and what kind of car are we talking about? Many cars will throw airbag fault lights simply because the system was temporarily disconnected and all that is required to sort it is an OBD reset.

A faulty airbag itself? Disconnectin the airbag and connecting a dummy load resistor across the connections will temporarily fool the fault check system until the bag can be changed.

Please note that I am not encouraging permanently bypassing the system and all precautions should be taken to discharge airbags properly before working on them, but the above tricks will get you (legally!) through the MOT if a 'quick fix' is needed.

[Riknos]

r11co said:

A faulty airbag itself? Disconnectin the airbag and connecting a dummy load resistor across the connections will temporarily fool the fault check system until the bag can be changed.

Please note that I am not encouraging permanently bypassing the system and all precautions should be taken to discharge airbags properly before working on them, but the above tricks will get you (legally!) through the MOT if a 'quick fix' is needed.

How is "fooling the fault check system" legal?

[r11co]

Riknos said:

How is "fooling the fault check system" legal?

Because the requirement is not that the airbags themselves are functional (as this cannot be tested for certain without actually triggering them), but that the system does not show a fault by the light staying on rather than going off after the pre-determined time, or not coming on at all.

It is a technical point but correct all the same. It is not uncommon for cars to be fitted with aftermarket steering wheels with no airbags. Fitting a dummy load in place of the originall steering wheel airbag will mean that any other airbags and active restraint systems in the car (passenger, curtain etc.) will continue to function normally and the car will pass the MOT. I wouldn't recommend anyone doing it, but people do!

Edited by r11co on Friday 14th February 13:46

[E65Ross]

Riknos said:

r11co said:

A faulty airbag itself? Disconnectin the airbag and connecting a dummy load resistor across the connections will temporarily fool the fault check system until the bag can be changed.

Please note that I am not encouraging permanently bypassing the system and all precautions should be taken to discharge airbags properly before working on them, but the above tricks will get you (legally!) through the MOT if a 'quick fix' is needed.

How is "fooling the fault check system" legal?

he's merely pointing out that it'll pass an MOT; I think the exclamation mark was showing his surprise that this is "technically" legal - in a sense.

[Spangles]

Remove the bulb. The reason for rejection is "A Supplementary Restraint System (SRS) malfunction indicator lamp indicating a system malfunction.". The reason for rejection where the SRS lamp was inoperative has been removed from the manual. Now you may get some testers failing you wrongly, you'd have to take that up with VOSA.

[thatdude]

Why is the light coming on in the first place?

[conkerman]

Check the connectors under the seats.

[TurboHatchback]

Warning light on = fail
Warning light not working = advisory

You can probably work out the answer if all you want is an MOT pass.

Hint:

Spangles said:

Remove the bulb.

[HumbleJim]

You learn something new everyday.

[paintman]

Crazy, but true.

The underseat connectors are, as said, often the cause. On two of the Peugeot 306s we had we had this issue. The cure was to cut off the plastic connector & permanently connect the wires.

Edited by paintman on Friday 14th February 16:28

[SteBrown91]

If its a fiesta mk6 likelyness is either the pretentioner/s have failed/been disconnected and reconnected with the battery on/been in a crash, deployed and not replaced.

If its the middle option any cheap ass code reader will clear the code, and it shouldnt come back. Or leave the battery unhooked overnight.

[r11co]

Spangles said:

The reason for rejection where the SRS lamp was inoperative has been removed from the manual.

Didn't know that - learn something new every day!

Having said that - a load resistor to keep the rest of the system working is still a better (and easier) option than taking the 'bulb' out as these days it is more likely to be a SMD LED.