I saved a very nice lady a heap of dough today with an MoT test failure for an illuminated SRS light. The airbag module had failed. No comms. She had already had it diagnosed elsewhere, and had bought a secondhand module from eBay. As any fule kno, these units are coded with the chassis number permanently, and it cannot be overwritten. At this point her regular mechanic admitted defeat and sent her to me. Now, whilst it’s very true that the chassis number can’t be overwritten, if you have developer mode and a working knowledge of technical German you can find the place where it compares the chassis number stored in SRS with the chassis number stored in the EZS. It’s as simple as changing ‘Ja’ to ‘nein’ and it will forgo that check. Jobs a good’un. So for clarity here, you can use a secondhand SRS module in a W211, as long as you can find someone with developer mode on Star and a little bit of cunning about them. You can also reprogram a United States market LHD R230 SL airbag module to work in a UK car. That one took me a whole day though!