dhbpac

Had some issues with left front level sensor so I took it apart, resoldered some of the PCB connections then sealed it up & reinstalled.

Everything was fine until the weather got REALLY cold, then I started losing pressure overnight. No biggie since it refilled just fine when I cranked it up in the morning. I figured there might be a cold-related leak and would fix it in when the weather gets warmer.

So now the weather is warmer & I'm starting to look at it. The LF level sensor was funky again so I plugged in my VCDS and collected some data. Graph of reservoir pressure is below.

I've since replaced the LF sensor with a brand new one, but the behavior is still the same (although I need to recollect data again).

It almost seems as if there's some type of controller or sensor issue.

Anyone have any ideas or experience?

PaperToast

toss up the exact codes you got from vcds if you can

dhbpac

PaperToast

how does the connector look?
someone else just went through a similar ordeal

dhbpac

dhbpac

Here's the new data, the reservoir pressure. Took a 40 mile trip to Costco. Kept the same level (2, aka normal) for the whole trip. Again the interesting pattern with instantaneous reservoir pressure changes.

Stopped for gas before I went inside (around the 1461 data point), shut the car off then turned it back on to keep recording. As SOON as I opened the door, it bled out pressure. I read that one version of this controller is supposed to change to level 2 when you park the car, but not this version (4Z7 907 553E).

PaperToast

sounds like its working normally
what happened when you opened the door is the self leveling doing its thing
mine does that all the time

dhbpac

Yeah, I've been into SSP_243 quite a bit. The more I look at this, the more I think there's a leak in the reservoir (aka, pressure accumulator) or somewhere in the manifold. It seems to improve with longer drives, I'm thinking because the temperatures are increasing.

The times when the pressure is highest is when the pump is on. The pressure drops when the pump goes off. The pump cycles less & less frequently, and the reservoir pressure seems to increase somewhat, with increased driving time. This chart shows the trend.

Maybe one of the fittings is loose ... able to hold pressure when the pump is on, but loose enough that it loses all pressure when the pump goes off. I don't lose any height overnight (except the first night after I changed the LF level sensor).

Thanks for your feedback. I will keep updating.
.

mike sharples

Is it possible that the air compressor is failing?? Mine did all sort of weird things,the compressor would cycle lots,parked up,driving etc.Found it just couldn't keep up the air pressure.I also had leaking front air bags too which didn't help,but once driving and the car was level,it would take along time to change levels.Also,the info I have indicates that the vehicle goes to level 3 when parked automatically,if its not,and pressure from the accumulator drops,maybe its trying to raise the car but cant due to no reserve air or a large leak.

dhbpac

Thanks for the idea - I have thought about this. Level changing seems to be fine, and not take too long.

I did the compressor repair kit by bagpipingany not too long ago. It was MUCH better after that, but he recently started offering a more complete rebuild kit so I might do that.

I have noticed that past couple of days it's been cold and the LF shock is down in the AM. They are new Arnotts with only about 4k miles on them (if that much). So I think I'm going to test for leaks first.