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Discussion Starter · #1 · (Edited)
HELP!! This is all new to me as i'm at the end of the line..
I have recently purchased a 525i touring, year 2001 - it seemed fine on the test drive and reasonable mileage at 70k.

The problem startered on the long drive home from collection when the self leveling suspension light came on.. and it was noticable the car was high one side and low the other. Took it for a check up they said it was one of the valves on the air compressor that was pumping to much air into one side and that would cost £600 to fix (Now i wasnt born yesterday) When he was explaining how it worked i noticed the the blue & red air tubes were not match at a connection block (i didnt say anthing just nodded politely)
I got it home and re aligned so red went to red and blue went to blue. Now this then changed the problem so the car tilted to the otherside, however with a difference as the ride height was fine when the ignition was on, although over night it would drop one side - turn ignition pump back up fine - so we were getting somewhere!! Oh no as i here you cry you got a air leak - well thats what i thought - took it to a different garage suspension airbags fine - i checked with soapy water all other joints - so thats part one

Part two - the wife rings says the batterys flat - aa come say the battery too small and its drawing amps (electrics not my strong point). So take it to another garage - they change battery to the correct size and confirm its drawing amps - so back the car goes in a couple of days time and auto engineer has narrowed it down to fuse 4 which i'm being told does - interior lights - alarm - front windscreen washers and suspension system. Ah i think is there no a link to the suspension problem droping one side overnight and the electrical fault?!!???!! - i'm being told its the multifuctional control module needs replacing at a cost of £200 for the part and lots of time in labour as the dash needs to be removed? - does it?? dont know?? (he didnt feel me with loads of confidence that it would fix the problem either)

Before i spend anymore money i would just like some advice if anyone can help.... i'm not sure if the two problems are linked or not .

Forgot to say now the fuse 4 has been removed it looks so far like the suspension isnt dropping anymore, although tomorrow morning will provide a better indication.
 

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Not too clued up on this system but firstly, from the data I have, fuse 4 is one of the supplies to the general module which controls and monitors loads of components, including the door switches.
However, the following is an extract from the description of the air suspension system

How the entire system works
>The system is controlled by a microprocessor, starts working when a door or lid is opened, and continues until approximately 16 minutes after the vehicle is left. The electric drive of the compressor makes the system independent of the vehicle engine.

The following signals are evaluated in the air suspension control unit:

- Consumer cut-off signal

- Height, left

- Height, right

- Terminal 15

- Road speed

- Engine ON/OFF

- Information on the status of the doors and boot lid

The bit about the system running for 16 mins after leaving the car and the fact that it is looking at door and boot status may be worth looking at. It could be that one of the doors/boot is not registering as it should.;)
 

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If it's dropping on one side then you must have a leak somewhere.

It's a problem we get all the time on coaches, if it stays up when running then it's nothing to much to worry about.

Some air systems will leak and finding it can be hard work especially if it goes down over a long period of time.

You said that it dropped on the other side when you changed the air lines over so it's going to be on that pipe somewhere.

Check all the fittings to make sure they are tight, if they are push fittings think about replacing them as the can leak more than the compression ones.
 
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