ucsbwsr

I am faced with an interesting scenario regarding my rear suspension and load leveling. My thought will be a little scattered but my goal is to paint a picture of what is going on and hopefully guys familiar with this can help me diagnose it.

Yesterday I took my rear KW V3s out to examine the bump stops and general condition of the struts as I from time to time can get a loud *BANG* when hitting an expansion joint or compressing hard on the freeway. I am in the recommended height range (at the very bottom of it naturally) according to KW and the bump stops looked good. I double checked the compression and rebound settings as well.

After reinstalling the KWs and the remainder of my interior I took the car for a spin to try the slightly different suspension settings I changed. A short while into my drive around the neighborhood I noticed increased banging, like I have experienced on the freeway but it was happening over everything. As it turns out my rear driver-side was dumped and I was rubbing, rubbing REAL bad, I limped the car home for a closer look.

My inital thought was a faulty compressor, air line, or something of the sort. Oddly my passenger side was normal. Once I was underneath the car I inspected the compressor and all the hoses and connections which are the "usual suspects." I even followed the air lines to the bags to see if I unknowingly damaged one while reinstalling the KWs, everything looked good, and the compressor looked fantastic, so fantastic it must have failed and been replaced by the previous owner.

I grabbed my laptop and plugged in with INPA and went to the air-ride adjustments, this was my first time doing so. I played with the actuator settings and was able to fill the driverside bag up to it's normal driving height. The bag was holding air just fine. I played around with the R/L settings and brought it back to a level height (according to my wheel-fender measurements). I unplugged and took the car for a quick spin not more than 1/2 a mile and my optimism was literally deflated and my rear driver-side was dumped.

I plugged back in with INPA and the read outs were 56mmL and -10mmR. I leveled the car out and INPA showed that they were still significantly different, now it read 56mmL and 20mmR. I also had a stored code 5F9B "signal or value above threshold test conditions"

I double checked the KW adjustable links and they looked fine so I thought the problem could be isolated at a faulty sensor (BMW 37146784696) I unbolted them from the KW links and subframe but left them plugged in. Interestingly both seemed to work fine, no physical damage and the readouts were essentially the same in INPA when I would test them by physically moving their swingarms.



SO, my compressor is good, lines are good, bags are good and hold air but my system for some reason thinks it needs to dump the driver-side when underway, and not just let some air out but let ALL of it out, so much you can squeeze it like an empty brown paper bag.

Does anyone know of a way to "reset" the sensors or controller and sync up the levels in INPA with what the car visually looks like? I understand there could be uneven tire wear or one strut possibly unseated (I will confirm this tomorrow) but I am doubtful that either of those could equal 20-40mm of difference.

Is anyone familiar with the computer or module for auto-leveling and which input, KW links or INPA settings, are proprietary for the car?

Now that both links were individually tested and seem to work well, I will reassemble them and see if the read outs in INPA are more in-line than before. I will also double check that the KWs are both installed a seated properly.

Since the car dumps while driving it must be adjusting to something and since my passenger side was reading a constant 56 through everything while I was manually changing it, it leads me to believe the sensor was stuck since during isolated testing it worked fine. I am hoping that is the case and everything works as it should when reassembled.

In the meantime, anyone have ideas?

Evan


This was after I got everything level the first time


Then this was the reading after I limped home and the driver-side was dumped again


This is after leveling the car once again, notice how the parameters for the passenger side don't change in the read out (although I did adjust it)


Codes


Code Translated
https://lh4.googleusercontent.com/-u...o/IMG_4900.JPG

rorschach76

I also have KWV3s installed and had a similar issue. Ever since i got the wagon one side has been continually dropping. So i was constantly using INPA to raise it again. I left for a trip and when i came back my wagon was really dropped to one side. The rear passenger was dropped 1 inch more than the rear driver side.

The following has given me a permanent fix.
-level with INPA (numbers dont match, but i physically measured center hub to fender on level ground.
-turn off production mode


It has been around 4 months since i last adjusted the height and it has not moved since.

ucsbwsr

PROBLEM SOLVED


Frustratingly the issue could have been solved with a closer eye on my part but thankfully the issue is resolved and it was nothing major compared to most air suspension woes.

Continuing my diagnosis from the day before I confirmed that both load leveling sensors were working properly and reinstalled then along with the wheels and took the car off the jack stands. I was still getting a 56 in INPA for the passenger side, I crawled underneath the car (difficult with how low my car is) to examine the sensor while under load and as it turns out the sensor swing-arm and KW link had flipped inwards. The sensors are designed to work with both them and the KW links joining towards the outside of the car.

The sensor and link flipping was likely due to my link being so short; running the KW link at the "lowest recommended setting" is short enough for the connection to flip inwards and therefore dump the opposing side.

If you run your E61 with a short KW or aftermarket link and raise your so the rear wheels are off the ground, make sure your link and sensor are properly orientated! If they are not you will surely receive a kind reminder when the car starts riding on bump stops,

INPA is a handy tool, I recommend getting acquainted!

Cheers,
Evan

rorschach76

Do you have any pictures by chance? Now you are making me want to lift my car and check the rear. I'm at -2 left and -14 right.

1Animal1

easiest thing is not buying bars and lowering it via INPA... surprising how much money you save

timmay77

Yup. My kit came with new links, which I did not use. Popped into INPA and lowered it.

RIHI

Is irt possible to lower the rear suspension with the BMWhat app?

ucsbwsr

Sorry no pics, the best way I can explain it is:

Think of the angle of your arm around the waist of a girl, this is the angle which the links and sensor properly work at. Now think of your elbow being hyper-extended, this is what I suffered from. You want your arm around the girl, not hyper-extension.



It appears my links and load leveling override what commands I gave it in INPA, hard to tell since I set INPA at a very similar level to what I had before (but a tad higher) and now it looks identical to what I was running previously. Turning off "Production Mode" was mentioned earlier, does this, or something similar, permanently keep the INPA settings? Also, are you the renowned Timmay from M5board?

Thanks for the info,
Evan

1Animal1

There are specific actions to perform on INPA for it to save the settings. I've given full instructions here fella

https://5series.net/forums/e61-touri...g-98941/page6/

rorschach76

I'll check the angle once the weather clears up and stops raining.

As for the rear reverting back to the previous settings. Turn off production mode. If it is on my height would slowly revert back to the pte adjustment height