Hi all, It went to a BMW specialist who managed to diagnose a faulty master cylinder and fix it within 2 days. I have been presented with a bill for £2500 (which includes the service and the disc and pad change - originally quoted at £1200). The question really is if this is fair to charge the extra £1300 especially as it has taken over 3 months. The charge pump is what was causing the problem originally, so I obviously don't mind paying for that.

Actually I just went to the garage for all the codes, and this is a print out from one program which was done by someone they called in: 5C DSC: Pressure-sensor test DSC actively switched no ABS control Stop-light switch: not actuated no ASC control no DSC contol Brake booster: passive no ACC control no HDC control The Win Star machine which is owned by the garage came up with these errors: 88 - Pre-charge pump 92 - Brake pressure sensor plausibility If anyone has any further ideas I'd be most grateful!

Hi, thanks for your help. They have replaced the pressure sensor twice in the abs valve block, but are getting error 5C which is low charge pump pressure or pressure 'out of acceptable parameters' I think. They have bled the system many times now and used gallons of brake fluid and they have done this using the computer (opening the nipples and pressing a button on the computer I believe).

Sorry for the delay, and I don't have the actual code. It is to do with the pressure from the charge pump when the self test runs at 20 mph. The pressure is low, and so the lights all come up on the dash - ABS, DSC, and also the '!' warning triangle. The garage have reached the end of their time with it as it is now 3 months, and although they are not charging for the 100 or so hours labour, I have a bill for about £3000 for parts which they have fitted which have not solved the problem. The list of parts is extensive, and would be a large bill even if it was fixed. A broken car and £3000 out of pocket is not good, especially as it would only be worth about £4500 in perfect working order.

The fault code that is coming up is 'Brake pressure implausibility'. Not sure what that means though.

Thanks very much - I'll try all of the above and report back!

Thanks MegaCraggy. There was nothing wrong with the car when it went in to the garage. It was for a service, MOT, and front disc replacement which was part of the service - these are consumable items these days I believe? I would be more than happy to get the car back exactly as it went in! If only I could turn back time.....

Thanks. Nothing's really changed with the wheels though. The rear tyres are newer than the fronts, but they were replaced over 6 months ago, and all are the same size. I'm not sure what you mean by live data - is it driving with a laptop connected to the ECU so you can see what's going on? They have a fair amount of laptops and software but I'm not sure if they have the same degree as a BMW main dealer. I'll wait and see if this new unit solves the problem, and then will have some difficult issues to confront. If the problem is fixed, how many of the new parts fitted will I have to pay for? If it is not fixed, can I take the car away and pay nothing? If the answer to the second question is 'yes', are the garage responsible for getting the car repaired elsewhere?

I don't think there is vibration now, but as I haven't had it back I don't know how it drives now. Brake balance has been measured on the MOT rolling road, and the system is being bled electronically as they are a proper Bosch service centre. The problem is the ABS/DSC light coming on and there not being a found cause for this. There is a £600 new Bosch ABS valve block on it's way from Germany now, so if this doesn't solve the issue, do I have to pay for it? It is a Bosch system in the hands of a Bosch service centre - I can't understand how it can be unsolvable.

Hi - thanks for the reply. The vibration under braking was through the steering - it was classic warped discs vibration. They have replaced all the flexi hoses and also the rear discs and pads too. The problem is that I won't want to pay anything to the current garage without the car being fixed, and as there is the new problem with the abs, is this something caused by what they have done or not? It's hard to say, although they have had the whole braking system to pieces etc.

Hi, My 2001 BMW went into an independent garage in mid-November for a service, MOT, and new front brake discs (because there was slight vibration under breaking on the motorway). After they finished the service and disc change, it failed the MOT on brake imbalance. They replaced the brake calipers, but no difference, and after trying a replacement ABS unit in the car they sent the original off for testing which came back as 'ok'. They exchanged a 'boost pump' and also the master cylinder. They replaced the brake calipers again just in case they were a duff set, but still no improvement. There is now another problem in that the ABS light comes on after reaching about 20mph, and they can find a problem. They took it to the BMW main dealer who suggested exchanging the ABS unit again, but the garage decided this was not necessary as this had been done already. They are still working hard trying to solve the problem, but I am beginning to feel that a brake problem really shouldn't take this long to solve. I'm not really sure what to do! I can't really take it off them as they know what's been changed and another garage may have to start again. I wish it could go back to how it was before it went, but the abs light must be related to something which has happened in the last two months. Does anyone have any suggestions please?