Air Suspension Problem

[EPDM]

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?

[Roman D]

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.

[SlickGT1]

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.

[Astrok]

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

[Motorsport1207]

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.

[ouzo12]

Originally Posted by Gregory891

@ 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.

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.

[trojanman]

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

[jcorreanyc]

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.

[Ricky Bobby]

^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

[Madwelshman]

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