Air Suspension Problem
 

I recently purchased an x5 4.8is 2004 model a week later the air suspension inactive has come up, the car is high on the front left and the height adjust buttons green light has gone off but if you rest the fault via diagnostic computer it all starts to work suspension goes up and down but after about 30 miles inactive again the errors read are height invalid and something about a valve (can't find the paper I wrote the fault codes on).

Any advice like where the sensors are on the car what I should try first...

Mr Q

Give us the code first.

Symptom typical of bad height sensor. These are user verifiable with a multimeter. Somewhere on here I put the pin codes and related. In a nutshell you have 3 lines for the air suspension. Ground, 5v source, and a variable voltage based on position. Runs between about 1, and about 4, volts.

Some height sensors also have outputs to the LCM for the HID aiming, so be cognizant of that of you have 6 wires vs 3 at a given connector.

You can disconnect the arm on the height sensor and back probe the wires easily.

If you have INPA it's easier since it tell you real time what the height sensor is reporting.

Typical fault is when the voltage for the height stays low and unchanging. Car tries to raise but voltage doesn't increase as expected. You get a fault.

Common reason for this is the shaft seal on the height sensor wears over the years, and water intrusion can occur. Then corrosion, then failure.

If you don't have a way to diagnose, and your symptom is suspension inactive and one wheel jacked up out of kilter from the rest, start with the easy to check item - height sensor on that corner.

If you have INPA, you can manually put the heights where you want them, then set it to ignore plausibility checks (or something like that; I forget exact terminology). This will keep the car at the height you set (assuming no leaks and stuff; it won't self-correct in this mode). That way you can drive around as usual every day until part shows up and you feel like changing it out. Then put it back into normal operation and clear fault. All happy. :D

By the way, this mode is the easiest way to experiment with different ride heights and stuff, too, since it's essentially full manual control.

Guys, i have a question - I. See treads about air suspension faults all over the forum but on other hand those who does not have issues dont say anything to countrweight, is air suspension really really problematic?

:iagree:

I've taken the time to learn the various functions and so forth over time just out of interest.

I have had 1 suspension problem in 8 years. $65 height sensor. I personally don't consider that as problematic, so there's your counter.

The reason this comes up is because absent the time, resources, and desire to understand and deal with problems, the owner is otherwise at the mercy of diagnostic techs. Those who have good ones do fine. Those who don't spend money chasing causes and solutions via parts and labor.

The only actual part/assy tbat I would consider somewhat pricey is the compressor unit.

@ MrQ4.8is. Could you please confirm you have four wheel air suspension? Do you have any error lights on your instrument cluster? Have you read any fault codes (yet)? Front left corner is high, would you believe that the right front corner is at a normal height - as well as the rear corners? Have you checked the front suspension for damage - I am thinking the height sensors and the links from them to the struts?

All of the suggestions given previously are spot on - you need any of the various bits of software to read your car's code (been there, done that, it works and eliminates troubleshooting). The compressor is unlikely as your problem is specific to one corner, hence height sensor related or the air strut yourself.

Low risk and moderate expense to replace the height sensor. My X5 (rear air only) gave me a dash light. Plug in INPA and it told me the specific height sensor to replace (no guessing about air springs, compressor, leaky lines, etc). Useful technology, you simply use the tool that works with it.

Sorry about the delay in reply, been a little bit busy but thanks for the response, appreciated.

I have a 2004 X5 4.8is it has the four wheel height adjustment. The instrument panel reads up with suspension inactive fault message.

I've noticed the front left corner sits high looking at it I'd say height is at it's peak and the front right is high but not high as the left front, due to this (I think) the car is leaning down at the rear but looks to be very even on each of the rear corners.

The error codes read after resting the faults and driving the car around until the suspension inactive came up on the instrument panel by the way this was within 5 miles, using a "Snap-On" diagnostics computer the faults that came up after are;

Anti lock brakes - 5F1E Variant code info (ABS/ASC/DSC) - 5DD7 Height invalid (EHC error air suspension).
Air suspension - 80 Front activity plausibility.
Instrument panel - BD Electronic brake balance (EBV).

Cleared the faults drove a round this time got to about 30 miles before inactive suspension came up on the instrument panel. This time a different diagnostic computer was used "Auto-Boss" and faults list was;

NAME: ABS/ASC/DSC (Dynamic Stability Control)
VALUE: 1 Fault - 5DD7 - EHC Ride-height control, ride heights,invalid.

NAME: EHC Electronic Height Control
VALUE: 1 Fault - 80 - Activity plausibility front right.

NAME: ZKE/GM (Central body electronics/GM base module)
VALUE: 2 Faults -
1 - Fuse or lead for load circuit 1
2 - Fuse or lead for load circuit 2.

NAME: AHL Adaptive directional headlights
VALUE: 1 Fault - 01 - Communication with stepper motor controller 1 disturbed.

NAME: BM/MIR (On-board monitor/Multi Information Radio)
VALUE: 2 Faults -
1 - Control unit reset
3 - PL line:short circuit to ground.

NAME: SMF/SM/SLM (Seat memory,driver
VALUE: 1 Fault - 12 - Steering column,radial:short circuit.

Sorry for the essay, will try the above suggestions and very grateful for the suggestions and replies, in the mean time any of the above mean anything to anyone please let me know.

Regards MrQ4.8is.

Mr Q

Sorry about the delay in reply, been a little bit busy but thanks for the response, appreciated.

I have a 2004 X5 4.8is it has the four wheel height adjustment. The instrument panel reads up with suspension inactive fault message.

I've noticed the front left corner sits high looking at it I'd say height is at it's peak and the front right is high but not high as the left front, due to this (I think) the car is leaning down at the rear but looks to be very even on each of the rear corners.

The error codes read after resting the faults and driving the car around until the suspension inactive came up on the instrument panel by the way this was within 5 miles, using a "Snap-On" diagnostics computer the faults that came up after are;

Anti lock brakes - 5F1E Variant code info (ABS/ASC/DSC) - 5DD7 Height invalid (EHC error air suspension).
Air suspension - 80 Front activity plausibility.
Instrument panel - BD Electronic brake balance (EBV).

Cleared the faults drove a round this time got to about 30 miles before inactive suspension came up on the instrument panel. This time a different diagnostic computer was used "Auto-Boss" and faults list was;

NAME: ABS/ASC/DSC (Dynamic Stability Control)
VALUE: 1 Fault - 5DD7 - EHC Ride-height control, ride heights,invalid.

NAME: EHC Electronic Height Control
VALUE: 1 Fault - 80 - Activity plausibility front right.

NAME: ZKE/GM (Central body electronics/GM base module)
VALUE: 2 Faults -
1 - Fuse or lead for load circuit 1
2 - Fuse or lead for load circuit 2.

NAME: AHL Adaptive directional headlights
VALUE: 1 Fault - 01 - Communication with stepper motor controller 1 disturbed.

NAME: BM/MIR (On-board monitor/Multi Information Radio)
VALUE: 2 Faults -
1 - Control unit reset
3 - PL line:short circuit to ground.

NAME: SMF/SM/SLM (Seat memory,driver
VALUE: 1 Fault - 12 - Steering column,radial:short circuit.

Sorry for the essay, will try the above suggestions and very grateful for any suggestions.

Regards MrQ4.8is.
Mr Q

Mr Q

Whats an INPA.

Mr Q

Hi,

Just bought a pfl e53 4.4l v8.

It needs a lot of care ( the cheapest on the market in this neck of the woods by far). Previously has a faclift version which I got rid of when the valvetronic started to act up when it got colder

Anyway, the instrument cluster says the ride height adjustment is inactive. The compressor works and the fault code says right ride height sensor is defect ( GT1). This I don't get. I assume there are only two sensors, one at the front and one at the back.

I also assume that as it has xenon headlights ( european car) then the sensors are in fact the same items and in this case with 6 pins which therefore controll the ride height AND the headlight beam height. I also assume that the defective one is the rear one as the car surely only has the rear height adjustment.

Am I correct?

I think there 2 sensors, once you take a wheel off, it is right behind the hub it is about 1.5x1.5 inch box with arm and with few levers attached to it. Somwhere in this forum, guys expressed that quite often it is not even a sensor at fault, all joints get stiff and dirty and that causes wrong output out of these sensors.. Mechanics discover that while changing srnsors but change sensors anyway because customer agreed to pay anyway.

What would you guys suggest if you don't get any codes. Can't find a leak. And left corner is always lower. No matter how many times I adjust it to normal height. New arnott units all around as well. Also, if anyone knows the part number for sensor, that would be great, because realoem.com shows 2 different ones.

Check the air bags
 

In my experience with my MB R 500 and my X5 the bags are the problem. I just replaced the front on the X5 and it's too long a story and I am not a good enough typer. My suggestion is reset and let car pump up and level. Using your hand with your fingers monitor gap from top of tire to fender flair. See which Conner is leaking. I found when it goes down the opposite side goes up! Soap testing bags does not work. Just replace them

Of you are getting the inactive code, then there is an issue in the electronics of the system, bad components ect... I had this last year and I found 3 of my 4 sensors the plug wires had corroded and broken. I had to get new pins for plug. At this point I have my left front drop about 1.5" overnight, upon startup the front inflate up to height, no errors. I have concluded my bags are 10 years old and may have a slow leak that cannot be detected with soapy water. I am currently changing the rear airbags with new Arnott and replacing the front struts with new Arnott airbags.

What ride height did you set it at after replacing? I just had both rears replaced in my 2005 3.0 and set at 700mm but to me it seems like it looks lower and feels like i can feel all bumps on the road.

Could someone please post a picture of the sensor, and it's location. This just happened to my car this morning. Thank you.

Guys, for anyone with an '04 and EHC2 suspension problems, the culprit is very likely your air suspension module or "brain". The '04s had a different part number, 37-14-6-758-452 which almost always failed over time. In '05, the module was updates with a new part which had new hardware and software numbers, 37-14-6-773-999. These were much more reliable.

Many of the unexplained problems with these systems are because of this older module. If all else is working properly (ride height sensors, pump, etc) and you still have problems, you should change this out. I did on my '04 and haven't had a single problem since.

^Same here - module was changed in 2011 to the 999 part, after I fixed my leaking compressor and leaking front struts my system has been working flawlessly

Hi guys

I know this is an old post but it relates to my problem, I have replaced the compressor head and piston seal, the solenoid valve and the two front sensors and regulator rods. The car will run for a few miles before the suspension inactive fault appears with the run flat symbol
I noticed that the fault came on after going around a corner which makes me think is is wheel area related, the last time I checked it the snap on unit showed plausibility fault on front left wheel.
I don’t want to replace the EHC2 controller if it’s not that, so any ideas would be appreciated.

2005 x5 3L all round air suspension

Thanks Welshman

For EPDM, the rear air bag system has a ride height sensor at each rear wheel. Diagnostic software will tell you which corner (I had this). They are cheap enough that you could replace both.

For Madwelschman, the most likely problem (software can help) is an air leak in one of the struts. Given the age of the car, it’s likely “time” (been there myself). Replace them in pairs, as the other corner is just as old. Arnott suspension exchange units are an economical way to fix this.

Thanks
Would I not see the car drop if they were leaking?

Leaks can occur in the folds and “hold” when the car is static. Air suspension systems are great, I like mine (rear only in my case) but time, pressure and usage will naturally bring them to the end of use. If they lasted 14 years, that’s quite long.

I had plausibility errors.....have a look at the ride height offsets... (circled in red below)

https://xoutpost.com/members/lvr-alb...8-19-06-04.jpg

The value is out of range which meant it worked until you drove or parked over something out of level and it gets confused again.

this happened to me and using INPA I reset only that corner bit by bit to bring it back within range...

I had this and replaced the regulator rod because it was stiff, I was thinking it was putting excess load on the sensor arm, when I checked the readings after I had 0 on three wheels and 1 on the front left. Before hand it would go to -1945.
May have to borrow my friends snap on unit again as I do not have inpa program

Ok will do thx! Finally have some time to get this sorted...

Does anyone know what causes active plausibility, this has now come up after going around a roundabout, reset the code and it did it again two days later and once again going around a corner.

Getting to the point I want to blow it up 🔨🔨🔨🔨🔨🔨

On the same topic...my "Suspension Inactive Fault" light came in for the first time last week for the first time. 2003 e53 175000 miles 4.4 Sport.



The interesting thing is that it was a very windy wind and I have a Thule box on top. I could feel the wind pushing the truck really hard. Then I stopped at my destination and the light never came back again.



I kind of wonder what happened...

Possibly ride height sensor overrides on curve yet has come back to the correct position afterwards and system is confused as to temp position earlier...:dunno:

Sent from my SM-A730F using Tapatalk

Did you look at the offsets with INPA? If it's out of range it will keep failing and reset won't work.

It should not be that excessive on a curve to cause that and they are new sensors and regulator rods
Just wondering if any other sensors could affect it bringing up this fault

Believe me I know your frustration but it’s not the sensors that cause it. The value if out of range will not be changed by putting a new sensor on, and all that’s happened is you’ve got it running whilst the offset is incorrect.

You can replace components all day but as I found if you don’t address the offset value you’re wasting your time.

Any time you then cause suspension travel eg going over a kerb at anything but square on or a sloping corner the system doesn’t know where to go back and up comes a fault.

Have a look at the values and see what you’ve got.....if they are correct then it’s time to check voltages from the sensor back to the module. You can do this live by getting someone to move the suspension (eg sit on bumper) and see changes in voltages at sensors.

Thanks LVR

I know the offset on three wheels was zero but the one that was causing the issue was varying between -3 and 1.

I have ordered the INPA software to see if this helps better than the snap on unit a friend has, I did check the wiring but could not see any damage to it but understand it could be the plug.

I replaced the valve unit because the front left was showing open that’s now good,
I replaced the compressor head and seal because I was only getting 11 bar, now I get 16 bar so that’s good.
I replaced the sensors and rods because I thought the sensors may be faulty due to the regulator rods being stiff.

With the voltage I think they were similar, around 2.5 v but will check when I get the software and let you know how I get on

Regards
Mad Welshman

I bet we all have the same front left sensor failing and going out of range.

It’s looking like this is a common problem, that no one has a solution for

Well... I fixed it on mine...

How did you get the offset back in range bit by bit. Was this all done in Inpa?

Yes, I used INPA to adjust only that corner bit by bit by doing the ride height reset and only entering values on that corner. Took a few go's as mine was out by quite a bit. Then I used ISTA to do a EHC reset (although I understand INPA can do that too?) and it played nicely ever since.

https://xoutpost.com/members/lvr-alb...8-19-06-04.jpg

Until of course other components failed (but that's another thread/story)....:confused:

Hope to have the software this weekend instead of using snap on unit, should give me more information ��