MP4.2+6.0

In order of work:

1. Run the sensor issue down in full. Inspect each wheel corner for any broken or dislodged sensors or their arms. If it then gets level again with any repairs, you may be done. Seems like the most likely problem given you have a mechanical code for a sensor, plus the combination of too high and too low codes together.
2. If no luck with #1, assume you likely have a bad air strut. Start diagnosing to figure out bad corner. Leave car parked on level ground in Jack mode and see if one corner drops first and more than others. Most leaks are in front ones. In front, the sway bar pulls both sides down if only one is bad, so you have to look carefully for which side is a little further down and the first one to be down more. Sometimes it help to check starting point height to fender with a ruler on each side, and then track any dropping.
3. Assume compressor overheat is as a result of #1 or #2. Shows why these issues needs to be resolved pretty quickly too ,or compressor wears out.

ltooz_a6_a8_q7

If you're gonna use the VCDS, you'll never fix the problem correctly, it's a controlled system, one thing fails, all related components show failures. Start reading air suspension, if you want to troubleshoot the problem yourself then read how I troubleshot mine. It only cost me $300 to fix. It's almost 2 years ago, still like original, cold warm hot days.
The mechanics are clueless because they don't understand what a control system is.
https://en.m.wikipedia.org/wiki/Control_system

Cheers and good luck,
Louis

Panagiotis Kyriakis

My new mechanic actually run a scan. My car was at the first mechanics on Sep 15th around 5pm, ie same date/time as the one recorded for the overheat error. There's very few faults stored before Sep 15th. There's apparently 52 occurrences of the overheat error. What exactly is the date recorded on the log? The first time this fault happened?

The first mechanic did not diagnose that error, even though it happened while he was working on my car, maybe due to his fault and it should have been clear to a mechanic that there's something wrong (the car was tilting A LOT before returning back to almost even a while later). He told me that this is normal, some times it takes some time for it to level, I shouldn't worry etc. Apparently you shouldn't drive the car if there's an air leak right? Isn't part of a mechanic's responsibility to diagnose an an obvious fault that happened while he was working on the car and advice the costumer on how to best take care of the car? I was clueless back then, had just bought the car a couple of months ago.

Jack88

Interesting, but I don't think it changes what it is you need to do to diagnose it. And yes, you need to park the car if it has a suspension fault. Step one it to put it in lift mode, then jack mode to disable auto leveling, and let it sit overnight. If no corner of the car loses any height over night, a suspension leak is probably not the issue and you can go from there.

MP4.2+6.0

+1.

Yes, date recorded is supposed to be the first date the issue occurred IIRC, but the board probably has hundreds of posts where the date is way off in scans, often as far back as to around when car was built. Whether this module and set of codes generally reads correctly, I don' know personally. Yes, car should not be driven with leaks, but again in practice a guess is by now a good percentage of owners are doing that, some aware of the leak, some not.

This seems to be sort of going round and round. A bunch of replies saying go get 'em and a dollar on top won't buy much still. Figure out what the issue is--with plenty of info and suggestions provided already--and take it from there. If the answer clearly points back to the earlier work--like a broken sensor arm that the scan dates say first occurred then, now there is more to follow up about...later.

Panagiotis Kyriakis

Actually the new mechanic diagnosed it. He told me there's a leak in the air strut and it needs to be replaced. I ordered a new once from Suncore (not reman, new). He also told that the compressor is probably going bad and there might be a problem with the sensors too. But he wont be able to tell before he puts the new strut in.

One weird thing that he told me is that labor for the replacement might be higher than the original quote. He gave me a quote for replacing the strut (250 if it matters) but he was like "Calibrating the new strut might take longer than expected, so the price might go up". Is this normal?

Jack88

No, your mechanic is full of crap, there is no calibrating of the strut. It bolts in and that's it. I will tell you that the Suncore new struts are not OEM equivalent. They do not provide adaptive dampening, and may have a relatively short life. There are zero aftermarket alternatives for new struts that are OEM equivalent, so rebuilds or OEM new are your only options unless you are okay with the degradation in ride quality/handling.

Panagiotis Kyriakis

Oh seriously? So he might be bull****ting me about the other problems too. Can you tell if the compressor is bad or not without having all the struts in?

Here's what he told me:


1. A leaking L/S Front Air Strut. The Air Struts have been rebuilt in the past by Suncore. I strongly recommend not buying off brand air suspension components because there’s a reason they are cheap; and it will cost you much more in the long run.

2. A Suspension Air Compressor that is likely bad: The compressor is noisier than normal and the air pressure its producing is weak. Once the L/S Air Strut is replaced, we’ll see if it does its job. Take note of DTC 01577: Fault Frequency occurrences (52 times) since memory was last cleared. You can see that it’s been overheated quite a bit.

3. Vehicle leveling sensors that may have issues. Note DTC 01780. We won’t know for sure until the calibration is attempted.

Of note: The rebuilt strut that is apparently leaking has been in the car for about 3 years. I have no idea if the strut indeed has to be replaced or it's just something you can easily fix. For instance, I checked the receipts of the previous owner and there is a receipt saying that there was a loose air line on the same side as my faulty strut and another receipt saying that they repaired leaks. So apparently an air leak doesn't mean the strut needs to be replaced and combined with the dishonesty of the mechanic regarding the calibration I start questioning that the strut is indeed faulty and needs replacement.

What I know for the car is as follows: When I put it on lift all the sides went up, but they were not leveled. After a while the supposedly faulty side (front left) started going down until it reached a min level (like in the attached pic). I think there's air being squeezed out on this side but I cannot tell where it's coming from. I put it on jack mode and nothing really changed over a couple of days, but I guess it cannot go any lower than that right? I didn't wanna start the engine over and over again cuz I didn't want to damage the compressor. Plus at some point the MMI stopped opening up so I couldnt change the suspension settings.

​​​​​​​Help people? I am totally clueless here..

Jack88

Okay, the strut going down while you watch means it is leaking! As I see it in the picture, that is as low as it goes, there is an internal bump stop that prevents it from going further. Your pump can be burned out from trying to keep it pumped up, that happens with strut failures a lot. A rebuild may bring it back, it's an hour job for an experienced mechanic and cost $40 in parts and may be worth a shot. As for the strut, the mechanic was right in that aftermarket parts are inferior to OEM, but OEM are around $1500 each new. I bought 2 used struts when both my fronts failed, 1 year later and 1 had failed and required me to rebuild it, the other is still fine. Total cost on struts is around $800 and 4 hours labor total for me. I would say that a new aftermarket strut is about the worst option available, even if they technically work, due to it having the incorrect dampener for the car.

So, whatever you do, start with getting the strut replaced and get a different mechanic. If everything works fine from there, go ahead and enjoy the car. Leave it in comfort mode if you think the compressor is on its last legs, that mode puts the least stress on it. Since you have said you aren't a mechanical person, I feel it may be a good idea to remind you that this car has an extensive timing belt service that is supposed to be done every 75k miles, and while you are generally okay pushing it to 90-100k miles, past that puts you at high risk of sudden catastrophic failure which will destroy your engine, so if you see no sticker under the hood indicating it was done or have no other record, know that you are probably running on borrowed time.

Tstealth32

As far at the calibration - he might be talking about the leveling calibration, but it shouldn't require that. Just swap out the struts, and you're good to go. I'd recommend finding a newer used OEM strut off ebay. Find an older model 04/05 with struts that have recently been replaced, and purchase those.