To start with, the engine management light and the brakes not being right are 2 entirely different things, so treat them as such.

The most common fault with diesels of this sort of age is the EGR valve clogging up - basically, this pulls some of the exhaust gases back through the engine again to clean them up a bit more. However, the valve that controls the gas flow ends up getting clogged by part-burnt diesel, which has the consistency of tar. The valve then sticks, either in the open or closed position, and you get an engine management light.

No guarantee it is that, but it's always a good prime suspect.

Regarding the brakes : it could be anything, from pads/discs worn, to a leak in brake fluid, a servo failing, or even the brake fluid (possibly) never having been changed in the last 9 years, and in need of that.

First step, open the bonnet, and find the brake fluid reservoir. DON'T open it, but have a look at it from the outside. If the level is low, then it needs topping up or the fluid changing. Also, if the level is low, then ask why it is low - could be a leak somewhere, which realistically a garage will need to get it up in the air to have a look at.

One other point : if at all possible, don't go to a main agent for this, they'll probably skin you alive. Hopefully, you've got a decent independent garage in your area.

Do you have a copy of the fault codes they found? Its worth bearing in mind that the car's "computer" can store up old fault codes for problems in the past which might have been fixed, but not had the codes cleared afterwards.

The proper way is to note down any codes, clear them, then take the car for a run and see what codes return.

The engine management light might be coming on because your car is at the right age & mileage for replacement of its diesel particulate filter systems. It might need a new filter, additive and glow plugs. But if you ask around on the Citroen forums you'll find it a lot cheaper to get it done at a reputable recommended garage rather than the dealer.

Peugeot cars have a similar system, and dealers often quote around £600 to sort it. But in reality you can get a replacement filter for around £120, £60 on additive and then a tenner for a local Peugeot Citroen owner with the Lexia diagnostic kit to reset the counters in your car's computer to tell it that you've fitted new parts.

Edited by Gibbo_Wirral on 05/08/2014 at 14:45