Well here we are again with suspension problems on an LR3. Unheard of!

I recently installed the Proud Rhino bump stop spacer kit. Following this, I found I couldn't lower the truck to access mode without it thinking there was an obstruction and popping back up to extended height with the 'clear obstruction' warning.

OK you say - the spacers are simply causing it to bottom out before reaching the expected lower height. Simple. Ah, but not so fast.

It is not actually getting down to the bump stops before popping back up. It will drop right to the stops if I use the GAP tool to deflate the bags, but for whatever reason it seems to think there is an obstruction before it ever gets that far.

That's problem 1. It's not a huge problem since I rarely use Access anyway, but it may be important as a clue to the real problem.

After installing the kit I put about 50 street miles on the truck with no errors (other than that mentioned above). Then Saturday I started getting the red rover of doom on the dash and the 'max 30 mph' warning while falling to the bumpstops when I exceeded about 40 mph (approximate - I didn't actually document the speed but it didn't occur until I got to faster roads). I cleared the error and took off again only to have the same thing happen. The only way to drive the truck was to clear the faults, raise it back to normal height, then use the GAP tool to lock it into Build Mode.

I drove it about 300 miles this way over the weekend, but today I ran over 100 miles with no errors at all - all good it seemed. Then bam- it came back and I had to use the Build Mode work-around again to get home.

The error codes I'm getting aren't consistently the same.

I seem to get C1A07 - cross articulation every time. I think this is actually causing the fault that lowers me to the bumpstops.

I may or may not get the following errors as well
C1A00 - control module
U0132 - lost communications with ride level control module

I suspect from reading other threads these aren't 'real' errors but are instead the results of the CAN buss not sending appropriate messages due to the other (C1A07?) error(s)

One time I saw C1A03 - front left height sensor


When I get a chance I'll pull the wheels off again and have a look at the wheel sensors and wiring but I don't really think I'll see anything and I don't know a good way to actually check the sensors beyond physical inspection.

I have no idea what the cause of the cross articulation error really is, but my current theory (and it's only a theory, please correct me if I'm wrong) is that an intermittent wheel sensor (front left it would seem) is reporting a wrong wheel height which the computer interprets as massive cross articulation causing it to panic and drop to the bumpstops. Because dropping to the bumpstops is what the LR3 seems to do for ANY error....


Is any of this related to the Proud Rhino kit? Is it coincidence? I have no idea. I hate diagnosing this stuff!

But any help you fine gentlemen can provide would be much appreciated. I need to get this sorted plus do some regular maintenance work plus a couple little upgrades in the next month in preparation for a Rubicon snow run in December.

So....er....I guess this is where I say HELP!

 

Don,

Did you recalibrate the suspension after installing the spacer kit? If not, I think that is certainly something you will need to do.

I had an issue where I would randomly get the cross-articulation fault, the red icon, and drop to my bumpstops. It happened after I installed adjustable lift rods. Instead of making the front lift rods the same height and the rear lift rods the same height, I opted to make each lift rod it's own unique height in order to get the calibration numbers all the same.

Well... the car didn't like this. So, even though it rode level and was calibrated correctly, it just kept throwing these random faults. Finally, after I took the rods out, and made the fronts the same length and the rear the same length and recalibrated again, everything was happy.

So, it could certainly be a sensor, but I would wager it's just a calibration issue and even if you recalibrated, I would go through the procedure one more time.

 

Thanks for the reply. I saw some of your posts about this when researching the topic earlier.

I tried to do a recal but had to wing it. My truck is currently running Johnson Rods and I re-install the stock rods when doing a cal. Remember how the suspension thought it was bottomed out on something when I tried to go to access height? Well with the stock rods that happens in normal height. So I ended up doing the calibration in off-road with stock rods and just adding the 55mm (I think that’s what it is – I’d have to look it up again) to the numbers.

To compound that, my drive isn’t totally flat. It’s fine side to side but is sloped down toward the street. Not a lot, but enough to make me suspicious of my calibration. (and enough to remind me to be sure the block the wheels when jacking…..but that’s a different story).

So I may indeed just have a funky calibration causing the issue. In theory just adding the spacer kit shouldn’t cause any need to re-calibrate. That’s its point, it doesn’t change ride height, it just limits up travel when you drop to the bump stops to keep bigger tires out of the wheel wells. But in reality it does seem probable that this could be my issue.

So that takes me back to my first problem – the truck still thinks it’s hitting something when I try to lower it when I know for a fact it will lower beyond the point where the ‘obstruction’ causes it to bounce back up to extended mode. Perhaps it’s lowering too slowly with the spacers installed and the computer sees it taking too long to reach the low set-point so interrupts that as an obstruction? Not sure. I can’t see anything causing it and as I said when I deflate the bags with the GAP tool it lowers right down to the bumpstops which is lower than it ever gets when I try to simply use access height.

I may end up pulling the spacers back out to see what I can learn that way since I’m pretty much out of ideas at this point. I won’t have time to do that before the weekend though.

 

Since you did get the sensor height code once have you checked wiring at the sensors, I seem to recall a thread about it being common for these wires to get damaged

 

I'll be checking it when I get a chance, hopefully this weekend. I just got home today and still have work to do, then I'm on the road the rest of the week so there won't be much progress for the next couple days.

 

I believe the only thing that can cause a cross-articulation fault is a failed sensor and/or bad calibration. I would definitely check the live values and calibration with your GAP tool.

Also, I suggest communicating with the GAP support team. They are super-knowledgeable and always willing to help. The calibration process is quite easy now after they came out with an Excel spreadsheet whereby you just fill in the numbers as you go. You need only provide the independent variables and the spreadsheet does the rest.

 

Spreadsheet you say?

I need to check the GAP site - I haven't updated mine or even looked at their site since I got the thing 2 years ago. It's a very handy gadget, but not exactly what I'd call 'user friendly'.

 

I'm home now and can finally work on the truck. To start with I decided to take some measurements to determine where things are currently.

In normal tolerance I couldn't get any sort of consistency in my readings so i went to tight tolerance. For each I would raise or lower the truck then drive backward/forward about 15' as suggested to allow things to settle.

My current calibrations:
LF 207 RF 157
LR 207 RR 160

All readings below are with Johnson rods installed. Note I cannot go to access height or it thinks there is an obstruction and bounces back to extended in an attempt to clear the non-existent obstruction. I'm doing this with the Johnson rods because when I install the OEM rods I hit the same non-existent 'obstruction' when I try to go into normal height.

(it's worth mentioning again that there is no actual obstruction - I can manually deflate the bags and set it down fully on the bump stops with no problems)

The numbers below are the height as read by the GAP tool and as measured wheel center to fender lip, read two different times (1st on top, 2nd on bottom)

Normal height, tight tolerance
LF 13, 20.5" RF -14, 20"
LF 10, 20.5" RF -10, 20.25"

LR -11, 21.125" RR 22, 21"
LR -15, 21" RR 24, 21"



Here are the numbers at off-road height, tight tolerance
LF 69, 22.75" RF 41, 22.25"
LF 65, 22.75" RF 42, 22.25"

LR 42, 23.25" RR 78, 23.25"
LR 40, 23.25" RR 77, 23.25"


What I've noticed here is that although the truck measures physically very even and repeatable (at least in tight tolerance mode) the GAP height readings are very different side to side and the readings change although my measurements do not, at least not much.

Question 1 - Could this large side-to-side height reading be the cause of my cross axle errors when reaching highway speeds?

(I suspect it could but don't actually know)


Question 2 - if it is, what can I do about it? The truck physically is sitting pretty straight as you can see from the actual tape measurements.

(I have no idea what to do about this)


Question 3 - could any of this account for why the truck won't lower to access (normal with stock rods) height without thinking there is an obstruction?

(I would not think so but again, not sure?)

 

As an aside, I would like to do a recalibrate in a local school parking lot which would be more flat than my driveway but since I can't put it in standard height with the OEM rods the best I could do would be to try calibrating in off-road height with the OEM rods and just adding in the 55mm.

 

Well, I'm still not sure what the root cause of my issues is but I've got a plan and I'm moving forward.

I reinstalled the stock rods and doubled checked that I still couldn't lower to standard height without triggering extended mode due to an 'obstruction'. Knowing I can deflate the bags and lower it all the way to the bumpstops, I can only assume the computer is thinking the rate of decent is too slow, hence the 'obstruction'.

Back last winter when I installed my poly bushings I didn't have any grease on hand so they went in dry. It hasn't been an issue. But perhaps with the addition of the Proud Rhino bumpstop spacers I'm getting just enough friction in the system to trigger the problem

So I picked up a tub of poly bush grease and I'm pulling each control arm bushing out, greasing them up, and re-installing. Since I'm reduced to working in my driveway on jack stands instead of on a lift like the last time, plus I'm dodging darkness and rain, it's going to take a while. I didn't start until about 1:30 and I only just put the driver's front A-arms back in place about 45 minutes ago. That gave me just enough time to clean up my mess before full darkness set in.

I'll get back on it again tomorrow afternoon, but the morning will be taken up by picking up my new-to-me RRC, so at least I have that to look forward to!

(I'm convinced the whole problem stems from the recent purchase of a D1 and the RRC - the LR3 is used to being an only sibling and is throwing a fit because it's jealous)

I'll report back once things are back together, but I'm not sure if I'll get it done this weekend or will have to wait until next weekend to finish it.

Onward!