Mikexsr

Mine's a diesel. I doubt it's the original given the car is coming up to 12 years old. I installed the new (second hand) ECU this afternoon, and am booked in to get it reprogrammed on Monday now. Although it's interesting what @J.R. said about just being able to clear the fault afterwards. If all works out I'll look at getting the battery changed. Bloody cars. Thanks for all your input!

This might be a really daft question, but does the 2nd fault indicate a battery issue? Presumably fixing that wouldn't solve my ECU issue? I've tested the battery and it sits at 12.25v when off and dips to 8.5v when starting. Occasionally it turns over a little slowly, but always starts. Maybe I've just got a couple of issues at once though. I should have definitely mentioned this earlier, but the airbag light initially came on about 8 weeks ago at a time when the car was starting badly. The garage told me that the throttle body needed replacing and it's been ok since then. As I said though, it does sometimes start a bit slower than normal (1 in 10 starts, maybe).

@Tilt I had a Bosch garage run diagnostics for me. They said they cleared one fault but were unable to clear a second. I don't have the tools to clear them myself. They told me I needed to replace part# 1C0 909 605 F and quoted £900. I just had the one from ebay delivered (£12.99). Fitting won't be cheap but I guess I'm going down that route. I had just been worried that it could be something else causing that part to show a fault, rather than the part itself. It doesn't seem to be a part that fails, typically. The report they gave me identifies two faults: 1. ChecksumError - ECU Defective 2. Supply Voltage B + Signal Too Low - Intermittent @Wino I looked at the fuse map after you said that and I couldn't find anything there either. I had done a fair bit of googling before posting here though and some people had seen airbag lights caused by fuses for wipers... no idea how that works.

Thanks for your feedback. I did repair the wires a couple of years ago but they've broken again and I'm not sure if wires other then those that are obviously snapped might also be faulty. I'll replace the loom once the MOT is done, but given that the car's done 200k miles I'm reluctant to spend money before it's got an MOT. I was quoted £900 for the airbag part (£1100 with fitting), but I've managed to find one on ebay for a fraction of that. Fingers crossed it does the job. NZ100 and Wino make me feel confident enough that the loom is outside of the airbag issue. I'll crack on and get the part fitted - fingers crossed! Thanks!!

Hello, I've got an airbag light preventing me getting an MOT at the moment. Diagnostics point to the airbag controller module which I'm booked in to replace. However, I am wondering if broken wires in the driver's door loom can cause the airbag light. I presume there are sensors in the door for side impacts, but I don't know if they would route though the loom. Mine does have broken wires that have been causing issues with the windows but I've delayed repairing them until after the MOT. This might have been a mistake. Can anyone offer any insight or advice? Thanks. Mike