Would welcome advice.

ABS/TCS light been on for a bit with non functioning systems. MOT coming up, and I understand that a functional ABS system is a requirement if the vehicle is fitted with it (is this correct?). Haven't VAG-COM'd it - this would probably be useful I agree.

The 40A battery-top fuse closest to the nearside of the vehicle was blown. I replaced this with lower rated fuse wire as a temporary diagnostic fix. The ABS pump is making a buzzy noise now post fuse replacement (audible from inside the cabin, so think I would have heard it before if it were normal), and the warning lights are still illuminated. Therefore, am I right in thinking that the most likely problem is knackered ABS pump leading to fuse failure (or success!)?

It doesn't seem likely that a wheel speed sensor has gone as this would surely not cause the fuse to fail?

So, what are the current costs of an ABS pump? I'm not bothered who makes it. This answer could result in the sudden availability of a number of car parts for sale on here

Are there any reversible causes of ABS pump problems? Would brake fluid contamination have any part to play, and when you drain the fluid, are there any procedures you have to go through to flush/drain the ABS pump?

Thanks for any help.

you are correct with the assumptions with the MOT. the ABS needs to be working. you other assumptions sound reasonable, but I don't know for sure.... the ESP/ABS/Hill holder ect went on my fiat recently, they plugged it into the computer, and it said front offside, they checked sensor nothing wrong, so a broken wire... they re-wired the front offside to the ESP controller and all was well... no blown fuses, so your descrpition of the pump noise, blown fuse ect, may well indicate the pump..... but I'm only guessing! you'll ave to get it plugged in to fault find I would think .. GL!

Reading the codes would be essential to find out what would be causing the light to come on. As you've replaced the fuse, it may just be a case of clearing the codes to put the light out. My theory is that an alloy 40 amp fuse will fatigue over time as they often crack rather than blow. In all the cases that I have seen with this broken fuse, the fault code has been 00301 - ABS return flow pump (V39). There are procedures for bleeding the ABS block if it has air in it which has to be done using diagnostic equipment.

Costwise, I saw a dealer invoice today for £500 ish for a non ASR unit fitted, a lot of money considering that it came to us as fitting a new unit didn't fix it, though a £3 fuse did. An ASR unit is around £750 + VAT and are dificult to find used.

Thanks for your advice. On driving a short distance, the lights cleared, so it looks like you were right fordfan about the fuse fatiguing. From a bit of research and the above it looks like wiring problems/sensor failure are at least as common as pump failure.

So for reference, the lights don't clear spontaneously.

Thanks again.