new and exciting LR3 suspension failures!

zelatore

Explorer
Ah yes, just when you think you've got it sorted something new comes along....


While on the trail this weekend the dread red suspension warning light came on and I found the front had dropped to the bump stops. Oddly, the rear stayed up. I cleared the codes but had a C1A00 - control module code immediately return. OK no problem - I'm prepared for this. I'll just use the GAP tool to manually override and inflate the front...except in this case although I could command the compressor to come on and tell the computers to open the front valves to let air in the valves weren't opening. A little experimenting soon showed that the rear valves weren't responding either. I could neither raise nor lower anything.

My theory is that the actual control module must be dead or at least not responding to commands either from the EAS or the GAP tool. So when I used the GAP tool to override and force the front to inflate the compressor would come on but without the valves opening (either at the axle valve or the compressor valve) there was no way to actually push air into the struts. The fact that both the front and rear were unresponsive is what makes me think the actual module must be at fault.

I ended up driving it home in stink-bug mode, with the front on the bump stops and the rear in the air. Made for an interesting ride, but at least it wasn't rubbing while underway. Yeah, I'm sure I took some life off the inside shoulders of the front tires but they're scheduled to go away this fall anyway.

I did all the usual checks of the wiring once it was home but found nothing amiss. So off it goes to the dealer...hooray.

I've been sitting on a Green Oval manual inflation kit for almost 2 years and haven't installed it thinking with the GAP tool I could likely self-recover from any probable failure. Of course, I didn't expect the computers to refuse to talk to the valves. So maybe I'll reconsider installing that kit after all.

Actually, I've been discussing things with a buddy from the club and we're toying with the idea of building a stand-alone manual over-ride. It seems the basic mechanicals of the rig are fairly robust. The struts don't often fail; even the compressors don't tend to fail without warning. Air lines or fittings don't often fail. It's sensors or computer related stuff that gives me headaches. Seems like it wouldn't be that hard to basically build a box with a few toggle switches wired to the front, rear, and compressor air valves and the compressor itself. Send 12v to the right valve and the compressor and it'll have to raise - you wouldn't need the computer for anything. Is it really that simple? You'd still need to either pull the fuses or use the GAP tool to enter build mode to keep a fault from dumping the air and putting you right back on the bump stops again, but when you take out all the fancy monitoring systems all you've got is a compressor and some valves. Pretty basic.

Of course being a Land Rover there's likely something I've missed that would stop this idea from actually working. Regardless it's worth some thought.

And before you ask, no, I'm not switching to coils. They simply won't work for my application.
 

perkj

Explorer
Did you disconnect the battery and touch the positive and negative cables together to try to rest everything?
 

zelatore

Explorer
No, but I did clear the codes several times. I suppose the battery trick could have helped but I wouldn't actually expect it.
 

dsm02c

Adventurer
Ugh, one more air suspension issue, you didn't think about just replacing the module instead of taking it to the stealership? (dealers in Dallas are poor, only goes in for big warranty items) (I am also guilty of wasting money on swapping out parts that probably don't need it)
 
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zelatore

Explorer
I did consider it but I'm really starting in in the dark as to the module. I think the module is a out $350 from AB plus I'd still have to have the dealer program it to talk to the system (unless I can do it with the GAP tool?) So just throwing expensive parts at it didn't seem like the best idea. Then again, might well have been far cheaper than what I'll end up spending.
 

zelatore

Explorer
So to follow up on this-

The dealer found the same error codes I did and also suspected the module. The codes however didn't make sense to them so they did some tests including a pin by pin test of the harness and found nothing wrong with the module or the harness. Although they had been unable to clear the module fault code (as had I) upon arrival, somewhere along the lines it cleared and didn't come back. They had no explanation as to why.

The only actual problems they could find were the air exhaust line from the compressor was somewhat melted and the line feeding the rear suspension valve block from the compressor had melted slightly (roughly in the middle) and was leaking a bit, though only when tweaked 'just so'. The air outlet is nothing new - it's been seen before, usually due to a compressor running excessively and heating the air a lot. The failure on the other line they hadn't seen before; it's in a very protected area behind a heat shield.

I couldn't see how this failure would have resulted in the symptoms I saw and they couldn't explain it either. I do know that it's working again, but I really wish I had a better explanation of how failure A caused symptom B so I could actually learn something from this whole episode. Instead I'm left with the nagging suspicion that there may be a lingering issue waiting to rear it's head at an inopportune moment.
 

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