When replacing the door cables yesterday, I disconnected the battery and waited at least the normal period of time before disconnecting the passenger door airbag.

I then unbolted the airbag and sat it on a flat surface with the outward side of the unit facing upwards.

On refitting, the airbag light came up when starting the car. Initially I thought I was unable to reset it with the Faultmate I have, but it turns out that I was in the wrong section of the software ( oops ! )

Anyways, the fault reads as the door airbag circuit too low resistance. I can clear the fault, but it comes back instantly. I have since repeated the procedure of disconnecting the battery, and then unplugging and re-plugging the airbag connector. fault still remains and can be cleared, but re-appears instantly.

The way I see it is that if I had unplugged it when live, the circuit would have gone open circuit.

What I dont understand is why its gone too low resistance? does that mean the unit has now gone closed circuit? Has it done that as a self protective measure from my handling?

Anyone know if they have some sort of self protection in them which I have disturbed ... or has it just been fubarred by unplugging it? anythoughts anyone? V8 or else ...

Too late now obviously, but when I did my door cable I didn't unplug the airbag - I left it connected.

I know of no "self protective circuit" they are relatively simple devices. I see there are a load of them on eBay - may be worth getting one from a breaker for £50?

Due to the nature of the air bag, whatever you do DONT try and measure the resistance to compare it to a known working one  

I did the other door by moving it out of the way leaving it connected ... oh how I wish I had left it alone now!

I think before I try the ebay route, I'll unplug it and then measure the error. It should then go open circuit. If so, I know its the unit. If it remains low resistence, then its a short somewhere ... not sure how that would have happened, but it is an RR after all.

Regarding other units ... dont they need programmed to the car? ( although I only see 2 wires, which I assume is +ve and -ve to it to fire. V8 or else ...

Hi,

I'd be very wary of trying to measure the resistance across the air bag - not sure what the firing current is - but I suspect not much.

Always check first that you've not pinched the wires anywhere in the door - could easily be the source of the prblem and make sure that the connector is back on the airbag the right way round...