Technical Airbag comms failure

[stevebrum74]

Last week whilst doing around 65mph, my car flashed up the airbag warning lights, passenger airbag warning lights, seatbelt lights, the yellow warning triangle and fuel cut off and stop start warnings.

All the codes lead me back to airbag lost comms. (Taking the module out and then doing a fault rescan shows same errors. My airbag control module is 51918659, and i can't find the same part on ebay, but i have found one that's marked 52056238, if i buy this module can i slap it straight in? Yes i know it will want an MES done on it ( I don't have that software, just a cheap generic code reader) but i wonder would it make my airbags ''work'' again? At the moment, we are struggling as don't want my kids in my car without a working airbag system. I already have a blinking mileometer due to unplugging the old blue and me module because it kept draining the battery.
Seller insists its brand new unused and requires programming,

 

[jrkitching]

Check the integrity of the wiring at the point where it enters the rear hatch.

Wiring faults here have caused exactly this kind of multiple failure in the past.

 

[stevebrum74]

Check the integrity of the wiring at the point where it enters the rear hatch.

Wiring faults here have caused exactly this kind of multiple failure in the past.

yeah its all been checked.

 

[puntodeltathema]

When you say "lost comms" is you reader not getting a connection? Or are error codes being produced. If the former, you can probably get your existing ECU repaired. Check out the likes of northernautotech.co.uk (others are available but this just happens to be one outfit I have used and got good service). But if errors like B0100 or B0101 are being picked up then the unit is only fit for a paperweight I fear. If your rear hatch wiring is good (shorts here fry the airbag ECU for some reason, as well as cause other issues) then also check your heater unit rainwater drain is clear, as water damage from undrained drips from the heater box is also an issue for the airbag ECU, situated where it is....

 

[AndyRKett]

What were the original error codes ?

Weirdly removing the airbag ECU and rescanning it is likely to give you an error with coms

 

[FiatMatt94]

I recently had to send of my airbag ECU to be repaired for the same issue, I can highly recommend Autotronics https://www.autotronics.co.uk/ who repaired my ECU, all in with a reset & an additional repair the ECU needed when it was opened up was £240 all together with delivery & they keep you up to date with whatevers happening, this way as well it's plug & play when it's all repaired/reset whereas if you get a replacement ECU it'll have to have a proxi alignment on MES to get it to communicate with the rest of the car

 

[stevebrum74]

The original error codes are u0422 fire prevention system status from BCM Invalid data received
U1726 sensing and diagnostic module (SDM) missing.

(The sensing and diagnostic module is the airbag control unit)

 

[stevebrum74]

When you say "lost comms" is you reader not getting a connection? Or are error codes being produced. If the former, you can probably get your existing ECU repaired. Check out the likes of northernautotech.co.uk (others are available but this just happens to be one outfit I have used and got good service). But if errors like B0100 or B0101 are being picked up then the unit is only fit for a paperweight I fear. If your rear hatch wiring is good (shorts here fry the airbag ECU for some reason, as well as cause other issues) then also check your heater unit rainwater drain is clear, as water damage from undrained drips from the heater box is also an issue for the airbag ECU, situated where it is....

No water damage here, the module was just dirty.

 

[stevebrum74]

Got the report back from the repair company, it seems the voltage regulator inside the airbag ECU decided to self destruct and took several components with it.

I have managed to source the same make and model ecu, I am assuming this is a straight forward swap, no need to do a proxi?

A couple of people say I don’t need too, and others say I do.

Thoughts?

 

[AndyRKett]

You will almost certainly need to do an alignment so the car knows how to address the new ECU

 

[stevebrum74]

Thanks for that, I’m assuming though once replacement module installed all the warning lights will go off? I need to buy the leads and MES but can’t quite afford it yet.

 

[puntodeltathema]

You may find there are codes which need to be cleared, and a proxi alignment is likely to be needed if you're fitting a unit that wasn't originally in the car.

Have a look at the "members with MES" register - there may be someone local to you who can help.

 

[stevebrum74]

You may find there are codes which need to be cleared, and a proxi alignment is likely to be needed if you're fitting a unit that wasn't originally in the car.

Have a look at the "members with MES" register - there may be someone local to you who can help.

Thanks.

 

[martinthomas747]

I've found you can interchange change ECU with part numbers, metal cased for metal cased units though. And then a proxi alignment on MES which is worth every penny !!

 

[stevebrum74]

Thanks for the info, and apologise for the late reply. I managed to source the same airbag module, same model same codes, plugged it into the car and it recognised it straight away, all the airbag warning lights went off. Ran a code scan using a generic reader and deleted old stored codes and now everything is Ok.

Thanks for the replies and advice.

 

[steveras57]

Thanks for the info, and apologise for the late reply. I managed to source the same airbag module, same model same codes, plugged it into the car and it recognised it straight away, all the airbag warning lights went off. Ran a code scan using a generic reader and deleted old stored codes and now everything is Ok.

Thanks for the replies and advice.

glad it worked out that easy for you!