Suspension Fault Issues

[BigBriDogGuy]

I was watching an episode of LR Time where they were working on a suspension issue on an LR3. They put soap and water on everything and eventually found it was the front valve block that was leaking. Replaced or serviced the block (can't remember which) and "Bob's your uncle".

At some point in the show, Christian (the DIY enthusiast), said that it was a good idea to cycle through the different suspension modes on occasion to keep them operational. That made intuitive sense to me, although I have no idea if there is anything to it.

So here's my deal. I have been getting the occasional random suspension fault on start up. Turn off the vehicle and start it again and it's gone. Drives fine in normal mode and I won't get the fault message for several days, or even weeks. There are no other signs of a suspension problem. My driveway is on an incline and if I pull nose in the front drops to auto-level once I shut down and exit the vehicle. When I back in, the rear drops the same way. I hear a clean *click click* and then a brief *hiss* and the nose or rear lowers purposely about 1/2". My thought is that has to mean the suspension is filling and raising as I drive or else there wouldn't be any air to release when it auto-levels. In other words, the air suspension is making minor adjustments on a regular basis as I drive in normal mode. To me, that says it's mechanically working on some level.

I thought back to Christian's comments about it being good to cycle the system on occasion. After getting a random fault today, I thought I might give it a try. I drove the car to a flat space in an empty parking lot and tried access mode and got the fault. Okay, fine. I turned it off and on again to clear the fault. When I got to the shopping parking lot where I was going, I tried access mode again and it worked perfectly fine. When I left that parking space I allowed it to auto-raise to normal mode as I got to speed and it did. No problem. Then I went to a different parking lot a few minutes away and tried access mode only to get the fault again. I cleared the fault and tried off-road and it worked fine. Drove away and it warned me that it would auto-lower if I didn't reduce speed and when I didn't it auto lowered to normal again. Bottom line, sometimes it works and sometimes it doesn't when I select the mode, but is seems to be working with minor leveling adjustments while driving in normal mode all the time. The common wisdom of the group is that it's the compressor starting to give out and that it will need to eventually be replaced.

Final thought, does any of this really matter? I mean, I played around with the auto setting on the steering column and after a couple days just turned it off. I found it more annoying than useful to have the steering wheel raise and the seat slide back every time I got in or out. Maybe the suspension height adjustments are basically the same. Am I going to lower it to access mode every time I park or am I perfectly capable of getting in and out in normal mode? Am I going to raise it to off-road mode when going down a dirt road to a camp site? For my purposes, am I seeking a solution to a problem that doesn't really exist?

 

[ftillier]

I think the system constantly makes small adjustments, though it's probably worth making sure it has full range of motion. I use access mode if there's something heavy I need to get in and out - my shoulders appreciate not having to lift things more than needed. When I'm on gravel roads I tend to leave it in normal height. When I'm on gnarlier stuff, I will go to offroad height (it will switch automatically if you pick some of the off-road terrain response modes anyway). I have a nice dent in my skidplate from when a short leg on a standard gravel road caused it to lower, and I forgot to raise it again when going over rougher stuff.

My take is if you know something is not working correctly, it's worth finding out what is going wrong, just so you can make an educated decision as to whether to delay a repair or address it sooner than later. More serious faults can drop you to the bump stops out of an abundance of caution, which can potentially leave you stranded if you need to clear some obstacle that you can't from the lowered position.

 

[Longtrail]

Here's the scoop with Christian and why he's recommended changing the ride height while looking for leaks with soapy liquid (and if I recall he found the leak in the front valve when changing the ride height). The typical pressure in the gallery (this is the pipes that connect between the compressor/middle valve and the front and rear valves) is typically much lower that the pressure in the airsprings and reservoir. I suspect the pressure is lowered in this part of the suspension (the gallery) to take the "pressure" off of the system (lower's wear and tear, etc.); when however you ask for a height increase the middle valve opens allowing high pressure air from the reservoir into the gallery; ultimately the front and rear valves are opened allowing that higher pressure air into the airbags and hence increase the ride height. Once the desired ride height is established then the valve to each corner is closed and then the pressure in the gallery is vented (the hissing noise you hear) to lower the pressure in that part of the system. By raising the vehicle Christian is looking to have the pressure in the gallery go up to about 250PSI and therefore increase his chances of detecting the leak (because air is more likely to leak at a higher pressure).

One other thing that is important; the suspension adjusts itself even when the vehicle is switched off; it's something like 30mins after key off and then every two hours after that; this is definitely covered in my long post on diagnosing suspension faults. To avoid this self-leveling issue and diagnose suspension system air leaks people pull the the EAS fuse (26); they then leave it for a period of time and see if it sinks on any particular corner.

When I was going through this I had leaks; I cleaned all three valves and added new o'rings - end result is no more sagging. Christian also serviced his o'rings (it's much cheaper than a new valve block and is actually very easy).

Your issue with the faults is very similar to what I was experiencing (random behavior of the warning light). Can you comment on the error codes you're seeing?

Motivation: I was interested to solve the issue as I, (1) Don't like warning lights - the engineers are trying to tell us there's an issue, (2) My wife wasn't confident driving the vehicle and worries about warning lights (way more than I do).

 

[Cthehentz]

If the LR4 is holding air over night, self level when parked or setting in the drive thru like it should and you are still getting faults it most likely the compressor. The wife Range Rover compressor just failed, the only odd behavior she said it seemed louder then normal, in the Range Rover it is dead silent so if she heard it running that was the sign it was failing. My LR3 had symptoms like others have stated, random faults, slow to rise and so on and like a cheap Charlie I bought the cheap brand off Amazon that caused more of the same issues. When I installed the new factory Hitachi it was like nothing ever happen once it leveled out.