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suspension fault and oil leak

345 Views 14 Replies 6 Participants Last post by  dtrain911
2012 Range Rover with 115k miles

A couple weeks ago I received a suspension fault for the driver’s front ride height sensor. When I looked at everything, I noticed the one lower control arm on each side was worn so I ordered both lower control arms for both sides along with ride height sensors for each as well. After swapping everything out and having an alignment done, I was still getting a suspension fault code.
I have a Foxwell scanner with the Land Rover software and it showed C1 A03-21 front left height sensor, similar code for the front right sensor and U04 21-68 invalid data received from ride level control module.
These are listed as intermittent and everything worked but the suspension fault keeps showing up on the dash. I cleared the codes and they came back immediately. Drove it yesterday and after parking it in the garage, the passenger side dropped over the course of the day both front and rear). No additional faults are showing on the dash or through the scanner.
I’ve been reading up on this in the forum (there were no shortage of posts…) and I think I have a plan of attack but wanted to be sure before proceeding.
  • Since the car will level out when it’s started, I can assume that the compressor is good?
  • Check for air leaks at the compressor, reservoir, air supply & each strut (not the valve blocks since a leak can’t be detected there?)
  • Clean the filter at the compressor
  • Pull the fuse for the suspension and let the car sit. This will indicate if a specific corner is the problem
  • It seems like the diagnosis for a bad valve block is a process of elimination. If I can rule out the other potential issues, then the valve block is the culprit.
I’ve also noticed an oil leak from the front of the engine. The oil is all over the front but higher on the passenger side. I will plan to spray with some degreaser and attempt to clean it so I can watch and try to verify where the leak is coming from. Anyone use a dye and have any luck? I’ve used a similar product on AC systems for leaks and it’s worked well. When I do start looking, any specific places to start consider how high it is on the passenger’s side?

Thanks for any suggestions.


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My 2010 and 2011 pretty simple - replace front struts and rebuild the compressors. No issues since. If your front struts are over 10 years old, renew them.

Check the date codes on the strut.

Particles of grit build up in the compressor piston. Grit and dust also block the filter/dryer inlet. The compressor needs to come apart to be cleaned. Same for the filter/dryer (or order new) So between those two issues you get reduced compressor performance and high comp temperatures.
Thanks - no issues with the air lines? just focus on the compressor and the front struts? For the compressor, is rebuilding worth it or should I go new?
I che
when you take the airlines out use DC111 on the sealing O rings this will keep them soft esp when its cold out
is this the correct product: https://www.amazon.com/1310476-Moly...locphy=9015329&hvtargid=pla-382786851799&th=1
I started the truck and let it run for a little bit. The suspension leveled out to some degree. The fender heights are as follows (first measurement is with the vehicle on and the second is about 5 minutes after it was shut off).
FL: 33-1/2" 33"
FR: 33-1/2" same
RF: 31-1/2" 30-1/2"
RR: 31" 30-1/2"

I'll check them again in the morning and see what they are after sitting overnight.

The video is the sound it's making on the passenger side. Does that sound like an air leak? I checked the struts and they are original. Is the best course of action to change both fronts and the compressor? Should I replace the valve block(s) as well?

One other question, if I have this apart, would it be smart to put new wheel hubs in the front? Current ones are original and have 115k on them. If they are close to life expectancy, I don't want to do them week later after the suspension is back together.
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Ride height this morning:
FL: 33"
FR: 33"
RL: 30"
RR: 30-1/2"

It did not sag considerably overnight... I just need something consistent happening to help diagnose this issue.
Did the shop perform your alignment in “tight tolerance mode”?

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That's a good question. I will call them this morning and ask them about it. I assuming he will say what mode???
When you have faults and leaks, usually fixing the leak with eliminate the fault. Unless its bee leaking for some time, then the compressor dies from over work. That's how people end up with multiple things wrong with their EAS. Check you date codes on the front bags. If they are from '11 or '12, they are pretty much guaranteed to be toast and have held on longer than average. Start there. I'm not a "throw parts at it person" but air springs have a finite life. If your compressor need rebuilding, the system will be slow to respond even when not leaking. Rebuilding what you have is is fine probably better than a new replacement. Your wheel bearings should be fine at 115k. But you mentioned replacing lower control arms as they were toast. Those might be originals so the rest of the control arms, ball joint, sway bar links, and tie rods probably need replacing as well. If all this stuff is original, its going to drive like a new RR.
Thanks - I will probably just swap out the front suspension and be done with it. Is this the correct rebuild kit for the compressor:

Seems like there should be more to it.

Found this one:

The ebay kit matches this one but it's in the UK

Thanks - I will probably just swap out the front suspension and be done with it. Is this the correct rebuild kit for the compressor:

Seems like there should be more to it.

Found this one:

The ebay kit matches this one but it's in the UK

What you your thoughts about changing out the valve blocks while I'm doing this other stuff?

Anyone treat these flare fittings for the air lines with something before removing? Since they are original, it could be a PITA to get them out. I'd rather not cut them and refit new ends if I can avoid it.
I think replacing multiple parts at a time isn't a great idea unless you are really confident in your skills. I would replace the front air springs. Good chance your problem is solved right there. If you do that, have an airtight system, and it adjusts slowly, then replace the compressor. I have a '99 P38 with the original compressor that still works fine. The valve block shouldn't need changing. To my understanding, a compressor that fits an LR3/LR4/RR Sport, does not fit a L322. Perhaps the differences are only connectors, I don't know. But there were also two brands used, AMK and Hitachi. I would pull your spare and remove the cover to verify what you have.
That sounds like a good start. I'll order the rest of the suspension parts along with tie rod ends and leave the air compressor for now. After rebuilding, I can test it and see if the problem is fixed. If it's all set, I can plan to have the front end aligned.
Definitely going to another shop as they one that aligned it before did not know what "tight tolerance mode" was when I called earlier. I found a local guy that is a master technician so I can schedule to have him look at it.
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