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Thread: EAS Fault Code: C1A07 Cross articulation

  1. #1
    Join Date
    Jul 2011
    Location
    Orange Park, FL, USA
    Posts
    152

    EAS Fault Code: C1A07 Cross articulation

    I have chosen to run oversize tires on my LR3 to gain tire choices in the highest load range. This has provided significant increases in tread life for my tires. It was soon becoming time to replace my last set of tires (49k+ miles!) and I was doing some research to find something of better quality. My last set of tires (Hankook Ventus RH07 in 285/60/18) were getting noisy, harsh ride and sort of had a mind of their own toward the end of life. I did choose this tire knowing the quality wouldn't be the most stellar, but they were only marginally larger than stock. I did have to move the front height sensor wires to the top of the frame to proactively avoid damage if rubbed.

    In my new tire search, I believe I googled "Best tires for LR3" or something. My search returned a YouTube video from RSW Solutions offering up the BFG All Terrain TA KO in 275/65/18. I was excited because I've run the BFGATKO forever on my Jeep with good success in all areas. The fitting of these BFG's are very tight though. So RSW Solutions offers software to overcome this problem (among other things). Using the RSW software, one can raise the vehicle slightly to allow for larger tires, using it's EAS calibration functions.

    So deciding this was the route for me, I pulled the trigger, bought the software and played with it a bit, then purchased the tires. Once I had the new tires, I performed the calibration as instructed (also a YouTube video from RSW). I gave the EAS a 3/4" lift and good to go...no rubbing. Then about 1 week later, I got the C1A07 Cross Articulation fault and she dropped to the bump stops. Fortunately, the software allows you to read and clear codes. After a reset, I was back on the road...for a few more days, and then the same. Since the height increase, I've gotten the fault code a few more times, but very inconsistently. A few days between, a couple weeks between, no rhyme or reason. So I've contacted RSW on a number of occasions, and at first, the guy was willing to help. But he finally dumped me saying to troll the forums, which I've done with no success. Now he just ignores all of my emails, which is quite annoying, considering I purchased his software (and the $1300 tires) based on his recommendation and experience.

    So I've been doing some digging on this cross articulation code. The dealer says "buy the spec size tire and stop messing with the suspension" (of course! and that's not happening). I use a really good indy, but he is in VA, I'm in FL and I can't get up there right now or anytime soon. I did speak with him though and his thought is that one or more of the sensors has come out of range and is detecting constant articulation when moving. I didn't really understand this because in my mind, the suspension is always articulating when in motion. He describes it as the sensor travels in and out of range and is fooling the ECU. His other thought is that the information the height sensors are sending to the ECU, since increasing the ride height, is now confusing it. However, he does think that the modifications can be performed with no ill effect to the EAS.

    Now bear in mind, prior to the recalibration at the higher ride height, I was having no problems with the EAS. No leaks, no compressor issues, no valve issues, no faults, etc. In fact, the only EAS issue I've ever had was a faulty wiring loom and sensor at the rear right corner in 2008. These were replaced under warranty by the dealer and I've since had no issues.

    So left to my own devices, I began scouring the RAVE manual. Now I've found some symptoms/faults that seem to jive with what my indy is saying. However, getting to the bottom of it and fixing it, is seemingly out of my league. Although, I'm willing to learn and do whatever is needed. On page 12 of the RAVE manual, it outlines some of the causes of major faults. And since for now I'm ruling out any of the faults that would have been caused by failed components prior to the ride height change, I'm focusing on the two that look like they could be tricking the ECU. Those being:

    Implausible articulation symptom detected
    and/or
    Constant articulation when moving

    So that's where I could really use some help here. Since many of you seem to know more about the EAS than I do. I'm including the record of my measurements taken during the calibration in hopes that it may help target the issue. One side note: After clearing the C1A07 code, it takes what seems a long time to raise the vehicle back to ride height and the message center displays "Vehicle raising slowly". I apologize for the lengthy post! And, THANKS!!!!

    Calibration recordings, the last measurement without a value was recorded after an approx 30 min test drive. Measuremnet taken from center hub to bottom of wheel arch (EAS value is first number-inches is second number):
    Front Left
    181-17.75"
    188-18"
    194-18.25"
    200-18.5"
    203-18.63"
    203-18.5"
    209-18.63"
    212-18.75"
    215-19"
    18.75"

    Front Right
    181-18.5"
    181-18.5"
    187-18.75"
    193-19"
    193-19"
    199-19.25"
    199-19.25"
    199-19.38"
    199-19.13"
    19"

    Rear Left
    170-18.5"
    170-19"
    176-19.13"
    182-19.38"
    182-19.38"
    182-19.25"
    182-19.25"
    182-19.25"
    182-19.5"
    19.75"

    Rear Right
    170-19"
    170-18.88"
    176-19.13"
    182-19.5"
    182-19.25"
    188-19.63"
    182-19.38"
    182-19.38"
    182-19.25"
    19.75"
    Brian

    06 LR3/D3 SE7, 275/65/18 BFG AT KO2's


  2. #2
    Join Date
    Mar 2011
    Location
    TX, US
    Posts
    204
    Any codes like "too many transitions"?

    Possibility you have bad cross link valves or other valves, leaks in your air bags.... See if you can get it into extended more and do some off road and see how it behaves, and what faults it is throwing.

    RSW is selling it, are they supporting it?
    PM me for Diff Parts, fridges, hitches

  3. #3
    Join Date
    Apr 2008
    Location
    Seattle
    Posts
    378
    To the best of my knowledge, the ONLY reason for a cross-articulation fault is a bad EAS calibration. Does the RSW tool allow you to do a full recalibration of the EAS? Your dealer should be able to do this also, for maybe one hour of labor.

    I have GAP's IIDTool and it can do this procedure. They recently came up with a handy spreadsheet, too...which makes it even easier to step through and perform a recal. I know that this doesn't help you in your current state, sorry.

  4. #4
    Join Date
    Jul 2011
    Location
    Orange Park, FL, USA
    Posts
    152
    Quote Originally Posted by HOUM_WA View Post
    To the best of my knowledge, the ONLY reason for a cross-articulation fault is a bad EAS calibration. Does the RSW tool allow you to do a full recalibration of the EAS? Your dealer should be able to do this also, for maybe one hour of labor.

    I have GAP's IIDTool and it can do this procedure. They recently came up with a handy spreadsheet, too...which makes it even easier to step through and perform a recal. I know that this doesn't help you in your current state, sorry.
    Thanks very much! I've been so busy lately and have only had a couple minutes to look at the GAP'2 user manual and calibration calculation sheet. But, it looks like this may be really helpful in sorting it all out even using the RSW Solutions software. I just need to decipher those formulas. I'll update the thread after I re-cal. Thanks again!
    Brian

    06 LR3/D3 SE7, 275/65/18 BFG AT KO2's


  5. #5
    Join Date
    Jul 2011
    Location
    Orange Park, FL, USA
    Posts
    152
    As we know, I have a different diag tool so everything in the GAP's manual isn't going to match exactly. But after reading it thoroughly, I have quick question that hopefully you can answer. In the GAP manual, the aids and calculation sheets, it refers to three measurements at each corner, 1. The calibration value (which I can get with my tool) 2. The measured height value (which a can get from my tape measure) and 3. The height value that is read from the "LCD cluster". All three values are required for the formulas to work. I do not have value #3. Maybe it's something the GAP tool is able to feed through the cluster, that my tool won't perform. Maybe the GAP manual is referring to the height value that is read through the LCD screen/nav (displays 4x4 info) that some vehicles are equipped with, but mine is not. So the question then, where is this height value read from? And then my further question would be; If it comes from the nav which I don't have, can I substitute those values with my measured ones (using them for two of the three values)? Thanks in advance for the help!!
    Brian

    06 LR3/D3 SE7, 275/65/18 BFG AT KO2's


  6. #6
    Join Date
    Jul 2011
    Location
    Orange Park, FL, USA
    Posts
    152
    Actually, now that I see the "height values" on the sample sheet, they don't seem to correspond with any other values. The height values are numbers like 4, or -6, or 10. Those wouldn't be anything close to the "measured heights" or "calibration values". Hmmmmmm...
    Brian

    06 LR3/D3 SE7, 275/65/18 BFG AT KO2's


  7. #7
    Join Date
    Apr 2008
    Location
    Seattle
    Posts
    378
    Brian, sorry to leave you hanging so long...I don't check this message board as often as others, and I've been on a few trips the last few weeks too. Yes, that 3rd measure are what GAP calls "live values" and I believe they are specific to GAP's internal algorithm for calibration.

    I don't know that you can get there using GAP's procedure with the RSW software. My personal suggestion would be to tell RSW to take their software and shove it up their ass. Get your money back...then buy an IIDTool from GAP.

  8. #8
    Join Date
    Sep 2009
    Location
    Loomis, Ca
    Posts
    831
    Did you also change the sensor rods or just do the software change most of the lr3 owners I know, and I'm not one of them, use the rods in conjunction with the software to run larger tires
    Trail Checklist:

    Rubicon (Buck to Tahoe in the rain/snow), Hell Hole
    ...

    96 DI 5" RTE, GBR 4.11's, ARB Front and Rear, 35" KM2's, custom front bumper, custom rear bumper, Roof Rack, Bottorf Sliders, Superwinch, RTE steering skid, Custom front diff guard...other and more to come

  9. #9
    Join Date
    Apr 2008
    Location
    Seattle
    Posts
    378
    I can't speak to the RSW software-lift....but with the IIDTool there isn't really a compelling reason to use both the software and the rods. Some do, and I think there is some advantage to it if that particular LR3 is at the edge of the sensor range (hard to explain but some are built such that they just don't have as much "adjustability") and I think it helps get very specific about height settings. If you just want to get a few extra inches though, you can do that with just the rods or just the software.

  10. #10
    hi sir, have you sorted the problem c1a07 fault?

    Peter

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