Air suspension issues - totally bizzare

[Homerlovesbeer]

Hi all,

After a frustrating process of doing a rear suspension refresh which included new integral links, ball joints (the left one was a nightmare), both track control arms and stabiliser links I now have a bizzare self levelling suspension issue.

Part of the ISTA process for a vehicle with airbag suspension involves removing the right underbody tray and disconnecting both rear bag lines from the air distribution block, one being a black line and the other yellow.

So I followed the process and the air was released from both bags allowing for me to do the suspension work.

To stop the pump from coming on if I had the car on I removed fuses 78 and 87.

So with the job complete ISTA mentions an inflate procedure for both rear bags before lowering the car. I don't have ISTA currently in a laptop, instead I use it as a guide on my PC and use scan tools for diagnostics and service stuff. I use both OTOFIX and Launch.

Upon turning the ignition on I get the "Self levelling suspension deactivated" message which I think is normal as I've just released all pressure from the system. I go into the OTOFIX Chassis/diagnosis/air suspension section and have a look.

I can run the pump to each bag and have it add air. I select each bag and run the test function twice to inflate properly.

Still the SLS message is active and all 3 ride height selection lights blink at the same time.

So I'm wondering why. I can run the pump on demand, fill the accumulator, vent etc ok.

So I'm thinking I need to reset the ride height and go about the process.

So I get the message about defaulting to the assembly line setting during the procedure and reverting to normal upon exiting it and the suspension not levelling until driving.

So I go for a very slow drive and it's not great as the height is so low still. I can hear the compressor running and after a while the rear goes sky high while the front is ok.

I go back home into the garage and try the levelling procedure again.

On the second drive the rear comes down and I'm thinking "great, problem solved" but then the ride goes shocking and I catch a reflection in windows of the car obviously fully deflated.

I gingerly drive home.

I still have the SLS inactive message. Nothing I do can clear it.

Now the compressor runs, stops and then it sounds like the distribution valve does something (I hear a quite loud an electrical sound from that area) then silence for about 10 secs then the compressor activates again, then silence for about 10 secs, then the distribution valve again, etc over and over.

There is now no longer an response to any bi directional commands I give the car, well it says activated when I select for example fill accumulator however nothing happens, or raise rear axle, again it says activated yet no sound no raising occurs.

Gutted I pull the air suspension fuses yet, and I have no idea how, the compressor is still running!

How is this even possible??



I am feeling depressed as the rear suspension work took days to do with the left ball joint dramas and I was so happy it was done and all I needed to do was get a wheel alignment and enjoy driving again.

I really don't know what to do now apart from take the floor panel off again and check the valve distribution block (for what, leaks? No idea what else).

Any help appreciated

Oh, and I tested each ride height sensor and they all show a voltage and ride height discrepancy from level with the front left showing in the 4's while the others are all under 1V.

Anyway, the car is now completely undriveable.

Any way to tell if the compressor is actually creating air easily? I'm wondering if it's running but not producing any pressure.

Thanks all

Edit: Oh and the rear bags are less than 12 months old and Arnott bags while the front struts are also Arnott's but unknown age as already replaced when I bought the car a couple of years ago and they appear to be in good shape.

[EODguy]

Did your ride height sensor flip over?

Did you get it out of line mode?
My great Zamboni ride with a pregnant wife has become the stuff of legends.

Did you do all your height settings on flat level ground?

Are your relays in the correct slot (can't remember & it's nighttime here so didn't look)

Did you get the overflow valve stuck in the open position?

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[andrewwynn]

Flipped level sensor is the usual culprit and/or the level sense bar is rusted at the ball joint. Pics of the 3 (four of two axle) sensors?

The sensor bar needs to be vertical and the sensor arm needs to be horizonal.

When the car is lifted it's possible for them to switch where the sensor arm is vertical and the level bar is horizontal.

This comes up about every 12-18 months on xo.


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[Homerlovesbeer]

Thanks guys,

With the car slammed to the deck it's hard to get a picture but here are mine.
I believe these are correct?

How does this explain the compressor running with the fuses out?

[Homerlovesbeer]

Originally Posted by EODguy

Did your ride height sensor flip over?

I don't think so? See pics.

Originally Posted by EODguy

Did you get it out of line mode?

Yep

Originally Posted by EODguy

Did you do all your height settings on flat level ground?

I did, in my garage.

Originally Posted by EODguy

Are your relays in the correct slot (can't remember & it's nighttime here so didn't look)

I didn't remove any so that shouldn't come into it.

Originally Posted by EODguy

Did you get the overflow valve stuck in the open position?

Good question.....how would I know this and check?

Cheers!

[Homerlovesbeer]

Still no joy fellas..... totally gutted.

[EODguy]

Originally Posted by Homerlovesbeer

I don't think so? See pics.





Yep







I did, in my garage.









I didn't remove any so that shouldn't come into it.







Good question.....how would I know this and check?



Cheers!

You can hear the overflow valve his when it 1st opens, but if it's stuck open you can't make enough pressure to hear it usually (after the compressor runs)

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[Homerlovesbeer]

Where's the overflow valve? Is it possible to unstick it?

[andrewwynn]

i think most of the self level gear is visible when you take out the spare tire holder in the back.

If the over pressure valve is stuck open you should hear the air hissing out.

I would say better odds one of the inflation lines is disconnected. You can use soapy water to help find a leak and also, new ≠ fixed, you may have a faulty air spring, though usually you'll get a sag on one side.

What are the values of each level sensor?

Did you possibly misidentify the fuses? Even if a relay is stuck shut you should have no power at the pump when the fuse is pulled.

[Homerlovesbeer]

Originally Posted by andrewwynn

If the over pressure valve is stuck open you should hear the air hissing out.

Nothing heard from the rear

Originally Posted by andrewwynn

I would say better odds one of the inflation lines is disconnected. You can use soapy water to help find a leak and also, new ≠ fixed, you may have a faulty air spring, though usually you'll get a sag on one side.

My best guess is a line has come open at the valve unit (I hope!)

Originally Posted by andrewwynn

What are the values of each level sensor?

3/4 had similar voltages with the front left being about 3v difference

Originally Posted by andrewwynn

Did you possibly misidentify the fuses? Even if a relay is stuck shut you should have no power at the pump when the fuse is pulled.

I posted a pic of the fuse box in the rear with the fuses pulled. If I pulled the wrong ones please let me know.