Wonky Allroad

My 2001 2.5 TDi Allroad has a suspension height problem. I've checked the threads and this seems to be a new one on this forum?

The things that seem ok:

Suspension lowers and raises manually by using the dashboard buttons and automatically according to speed.
There's no suspension warning light showing on the dashboard except occasionally (see below)
The car doesn't sag at any corner or one end
The car doesn't lose height when parked up/overnight etc

The things that seem dodgy:

The car isn't laterally level i.e. the passenger side is lowering more than the driver's side. This becomes more exaggerated the lower the suspension goes - like two very fat people are sat on the left side of the car!

Going to Level 1 takes a long time - caused the warning light to appear when I tested it today. Car ends up on a 20 degree angle!

Handling/steering at speed is a bit odd - see above!

I've been Googling and I have a theory:

the level sensor and headlight level sensor are apparently linked (?). I recently had the headlight bulbs replaced (got caught out by a blown bulb when it was getting dark, asked dealership to help rather than removing out all the plastic and hosing myself under torchlight) Could this have caused some kind of fault in the suspension level calibration?

I've read about a 402 mod where the height sensor is recalibrated - does this sound like a possible fix? Any other suggestions?

does seem like your suspension has gone out of calibration, and that's probably a good direction to start in.
Most common fault with these units is split bellows, which cause the car to sink, or the compressor to run all the time

Quote:

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Originally Posted by Kyojitsu

My 2001 2.5 TDi Allroad has a suspension height problem. I've checked the threads and this seems to be a new one on this forum?

The things that seem ok:

Suspension lowers and raises manually by using the dashboard buttons and automatically according to speed.
There's no suspension warning light showing on the dashboard except occasionally (see below)
The car doesn't sag at any corner or one end
The car doesn't lose height when parked up/overnight etc

The things that seem dodgy:

The car isn't laterally level i.e. the passenger side is lowering more than the driver's side. This becomes more exaggerated the lower the suspension goes - like two very fat people are sat on the left side of the car!

Going to Level 1 takes a long time - caused the warning light to appear when I tested it today. Car ends up on a 20 degree angle!

Handling/steering at speed is a bit odd - see above!

I've been Googling and I have a theory:

the level sensor and headlight level sensor are apparently linked (?). I recently had the headlight bulbs replaced (got caught out by a blown bulb when it was getting dark, asked dealership to help rather than removing out all the plastic and hosing myself under torchlight) Could this have caused some kind of fault in the suspension level calibration?

I've read about a 402 mod where the height sensor is recalibrated - does this sound like a possible fix? Any other suggestions?

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It could be any number of things, you will need a fault code read to diagnose the proble. I would not try the 402 MOD without finding the fault, i would assume it doesn't just loose its calibration more likely a fault. have you been in very heavy snow (May move height sensor) or is it freezing by you? It is more than likely a stuck/faulty height sensor or could be a stuck/faulty valve. get a scan for faults 1st.


Andy

Thanks for the advice. I'm having it checked tomorrow at this place in Coventry http://www.thevwaudispecialists.co.uk/ so will report back on what's found and let you know what they're like as a service centre.

Did you ever get to the bottom of this problem?

To be honest no. They found some minor fault codes but appeared to reset and now works fine. On one of the cold days last week I was having a second opinion inspection (didn't buy the findings of the first), reversed the car out afterwards and the suspension warning light was on. Momentary panic. A few seconds later it clears and has been normal ever since - thinking the cold has part to play here...however I did notice the headlights started to level adjust properly, whereas before I thought they were just really poor!

NB Having discs and pads all round replaced plus passenger side trackrod end ball joint on Thursday at a place in Brum called Frontier Volksworks. Will let you know how I get on.

Wonkiness has returned. Got specialist to take a look and found an intermittent fault stored as 1400 which related to thermal cut out. Compressor working away, can't get a level so cuts out - makes sense.

Also found battery was slightly under voltage (new 3 months ago mind). Bench charged battery, retried and tested suspension all ok. Take it home and end up with clown car effect with passenger side much lower than drivers - it looks like drivers side is stuck at Level 3 or 4 whilst passenger side is doing as it should.

Just crawled under car to look at wiring loom into compressor and all looks ok, squirted WD40 in there. Checked connection to pressure sensor (assume this is the big metal cannister in the LHS of boot compartment??) all seems fine.

I'm stuck - compressor works, airbags work, control on dashboard works, o sagging on corners, no warning light on dash - just drivers side not responding, meaning lateral wonkiness. Aaagh! :mad:

Any ideas? Can things be reset? Valves blocked?

PS tried lowering car with engine off, ignition on - seemed to even things a bit....?

I would inspect the level sensor on that corner first, is very possible it could have been knocked out of old position or something got bent, just check both sides and see if they look symmetrical.
Could eliminate it if you swap it over with other side and see if problem moves to other side.

Are the sensors easy to locate? I assume they'd be close to each airbag?

Very easy....take the wheel off and its the thing with a wiring connector and a link arm to the bottom suspension arm. There the same sensor on every corner. Before my front left (G28) sensor went faulty i would get the suspension mil flash on every so often. Also the front left height would be lower than the rest of the car.
Have you had the suspension height calibrated?