Need Help re: Level Control System Failure

[ard]

Mike-

So the compressor was working- the suspension would go up, but one side began to drop.

Then you replaced both airbags

Now you have nothing- no compressor, system bottomed out.

Correct?

[mikeetastic]

Ok I removed the compressor and pUT 12v direct and it seems to be working.. wtf!

I checked the fused under the globe box and all seems to be ok.

So bnew bag on one side and a non working air compressor. Anything else I can check before I get a replacement compressor?

[mikeetastic]

@ard nope. I saw the car sagging on the side so I replaced one airbag and deflate the other. After completion now airpump compressor won't inflate both bags :-(

[the_ulf]

i'd recommend you hold your horses on buying a new compressor for now. the whole function is a pretty simple "if this, then that" scenario. like "if ride height is low, start compressor until ride height is ok". so obviously there's something stopping that from happening. if the compressor works on your bench, there's no reason why it wouldn't work in your car, so the problem is further upstream. have you checked that the level sensors are all working correctly? at this point it's probably wisest to plug into the OBD and try tracing the fault through there instead of blindly throwing more money at it and hoping that it miraculously gets fixed.

[mikeetastic]

What do you mean by start compressor until ride height is ok? Does our e70 has this option or its just automatic when the car starts?

[the_ulf]

that's how the system works. it's self-levelling. it monitors the ride height and adds or releases pressure accordingly. that's what the sensors are for. they tell the system what the level is. you *have* checked the sensors, haven't you?

[mikeetastic]

I havent. Are those the 2 near the rear shocks with like an L shape arms? How would I go about in checking them if they work?

BTW thanks all for the assistance.

Edit: come to think of it, I might have jack the car too high because i was testing this with 2 wheels removed. I will lower it tomorrow and see if compressor pumps and inflate the bags.

[the_ulf]

check out the attached wiring diagram. HSHL+/HSHL/HSHL- (left), HSHR+/HSHR/HSHR- (right) are the sensor outputs for high, normal and low ride height for either side. there's obviously also a supply voltage going into the sensors as well. see if the supply voltage even gets to the sensors, your problem could be something as simple as a broken wire. measure supply voltage on both sides, get a reference value, see if it's the same both sides. ideally you should plug into the OBD to monitor I/O activity and see what, if any, signal arrives at the control module.

alternatively, find a car breaker and see if you can grab an identical tried and tested replacement sensor and swap your sensors, see if the problem persists.

i'm presuming you checked the solenoid valves that are part of the compressor assy, to see if the compressor, while it works, actually delivers air where it needs to be or if the pressure release valve might be seized. it's a simple enough system with a fair amount of things that can go wrong.

[Nanniepoo]

Originally Posted by mikeetastic

I havent. Are those the 2 near the rear shocks with like an L shape arms? How would I go about in checking them if they work?

BTW thanks all for the assistance.

Edit: come to think of it, I might have jack the car too high because i was testing this with 2 wheels removed. I will lower it tomorrow and see if compressor pumps and inflate the bags.

I bet it will. Vehicle thinks rear is high so no reason to kick on the compressor.

Pretty sure the DIYs mention slowly lowering the rear to allow the compressor to fill up the bags...

[mikeetastic]

Yep you are right

As soon as i installed the 2 rear tires and remove the rear jack stand, fire up the car the air pump filled the air bags..

Car is all good now. I'm sorry everyone, I didn't know that the car has an auto level and needs to be lowered to the ground.

Question though, is there a kit for our car to lower it on all 4 lowering springs? Reason I asked is I bought another bag and the 2 alone is already almost $400 new.