a6 ecu problem? water in the electrics? any advise out there?

[darby7]

hi all
i have a 2000 a6 1.8t avant. i had only driven it about 500 miles after purchasing it (i think the bloke new about the problem....)
i started getting some idling problems. at first the idling movement was only small, it moved maybe between 900-1100 when the car was stationary. it would do this for about a minute but then it would go back to normal. this may happen twice a week. a little while after that i had a number of different light bulbs blow on me over the period of a week. just after this happened the idling problem come back but worst so i stopped driving the car.
i left it a couple of days, went back to try it and the idling was now normal but now brake pedal was now solid! i tried to drive the car to test but to stop i had to push down the pedal with all of my force.
i'm now really worried about my new car that i've blown all my money on!
i left it for a couple of days to test, the brakes are now back to normal but the idling is worst than ever!!!
i tried to investigate only to find that water has got in the passenger side and saturated the passenger foot well. i have dried it all out but the problems remains.
i've spoken to a few people who think it may be the ecu as there is a number of problems that have occured at the same time, audi didn't really comment when i spoke to them for advise, they just want around £150 just to put it on the diagnosis machine!
is there anyone out there that has any clue what is going on with my car?
has anybody had a similar problem?

any help would be really appreciated as i need to get it repaired and need to go the cheapest route using used parts if possible....? thanks

 

[darby7]

hi, spent some time on the weekend looking at the car. i cleaned out all of the drain channels + underneath and around the battery & the pollen filter. i'm confident that water can no longer get in the car (i left the hose on it to check) now i know that the water problem is not going to get worst i now have to try to get the problem fixed!
on starting the car it know just cuts out when the idling goes to it's first low point. if i put my foot on the pedal i may be able to keep it running but i can have my foot to the floor and the revs go no higher than 3000 rpm, just as i take my foot of the pedal the revs go up slightly before dropping. i don't know if this has any significance?
i now think that the vacuum problem suggested by "audi5e & pete tdi" (top blokes) is probally more likely than the ecu that was suggested before, well at least i hope anyway!!! i tried to check the hoses but could not hear any leaks over the engine noise? should the noise be clear? is there any other way to check this? even though the hard brake pedal & failing brakes has not happened for some time but the bad idling + cutting out is constant, do you still think that it is a vacuum problem?
one thing i do not understand is that on starting the car the dash check says "OK" + all the lights go out as they should. i thought that a fault should be showing somewhere???
any more help or advise would be great. thanks

 

[darby7]

oh dear!!!
after a mission getting vag-com to work on the laptop i eventually was able to scan.
here are the faults..........

17544 FUEL SYTEM TOO RICH
17536 FUEL SYSTEM TOO LEAN
16684 RANDOM MULTIPLE SYSTEM MISSFIRE
16685 CYLINDER 1 MISSFIRE
16687 CYLINDER 3 MISSFIRE
16688 CYLINDER 4 MISSFIRE
16686 CYLINDER 2 MISSFIRE
17925 MAIN RELAY (J271) ELECTRICAL MALFUNCTION

these are the main faults that i believe relate to the problems i'm having, the others were minor bits a/c, alarm etc.....
there was a part number mentioned.... 4b0 906 018 bf component 1.8l r4/5bt g 006. i do not know if this helps.

any advise to what to do next?
i guess the main relay needs replacing asap (what one is the main one? is it with the other relays?) but any advise as to where to start or what parts to look out for would be really appreciated.

is it possible it still could be the suspected vacuum hose leaking or do these fault codes suggest something else????
thanks