Yes after completing, for example, a guided calibration; the GAP iiD tool will have a pop-up bubble saying to push EAS to re-activate. My question to GAP was should I push this and to re-activate what? They just answered YES (confusingly to me as I need to understand why things are), so anyway I've been racing to push the toggle within the 5 second countdown it gives you to do it. I have not noticed any difference between pressing the toggle or not. I posted a pic of it.

Example; start the LR3 up, compressor will run to top off compressor, no faults, all is well in the world. The second you touch the EAS toggle to raise or lower the LR3 the orange suspension light will pop on the dash, which disables the ability to height select and the ability to choose special programs (terrain modes). Sometimes it will go from orange to red. If I was to drive, of course the orange turns to red because of the speed/ stability concern. The fault is always the same: C1A13-64 (AF) Pressure does not decrease when venting gallery - Algorithm based failure - signal plausibility failure.

Today for no reason I can explain I was able to get the LR3 to lift to normal and off-road height by pressing the EAS toggle while I was seated in the vehicle without the fault triggering as it ALWAYS does. Usually I can only lift it by doing the guided calibration, and sometimes by utilizing the ADJUST HEIGHT function (usually this function just blinks ed and white and doesn't do anything). I was so happy, I left it in off-road height like that for 20 minutes then tried to lower it; I heard an initial burp of air from the compressor then the orange light and same fault triggered, doh!

I also removed the front driver's side headlight to inspect the wiring harness connector that is tucked way in the front of the driver's side wheel well, looked good. I've inspected the wiring again that goes from the compressor and center reservoir towards the front of the vehicle. I haven't checked the continuity of every single wire but have inspected very closely for worn, torn, frayed, excessively bent wires, tooth-brushed off the dust on connectors, etc. It all looks good for whatever that's worth.

This counts down from 5 to 1

 

...did the GAP guys say what causes it?

 

No, he didn't give an explanation but said that I should press it. For me it doesn't do anything whether I hit the toggle or not and doesn't affect the effectiveness of what I've programmed (at least as far as I can tell).

Next up, got some great feedback from emailing RSW Solutions LLC; they have a pretty good webpage that explains the general workings of the air system and troubleshooting, etc.

https://www.rswsolutions.com/index.php/mkiii-eas-system

I have to say I've been very impressed with everybody's willingness to help. I really feel at home in the off-road community as it has mirrored many of the attributes of what I've enjoyed about my career in the military. So thank to you all.

RS Solutions said "This particular fault code is an inferred fault. Meaning, No direct sensor measurement triggers this fault. There are multiple sensors and timeline information which are put together that the air suspension ECU uses to determine this fault. This fault code is a calculation. This means that the parameters used in the calculation can be changed in the air suspension ECU programming. Are you certain that the air suspension ECU was coded for the correct compressor? (Yes) IT could be that this remanufactured air compressor is out of tolerance and triggering the “C1A13” fault condition. (THIS) Or perhaps the air suspension ECU is not operating on the most recent flash. (I'm on the most recent)"

I had told RS that I'm also getting this when I use the stock Hitachi compressor however he said it's very common to get this fault with old compressors and to purchase the compressor exhaust valve rebuild kit and install. It is a fairly simple job.

So maybe I'll do this as I can't afford a new Hitachi or AMK as much as I'd like to.

 

....maybe reloading the compressor software wouldn't hurt? I don't know if GAP has one for the Hitachi.

 

Thanks and yeah, I’ve re-installed the latest version in the GAP tool even though it already had it and have re-flashed the ECU about 5 times now hoping for some type of black magic fix. No dice so far.

 

...from a component standpoint, I'd be focused on:

1. Center valveblock - verify tubes are correctly connected.
2. Height selection switch.

...and from a software standpoint:
1. Re-install Hitachi compressor firmware.
2. Recalibrate EAS.

 

Thanks for the investment in helping me out.

Here's what I'm thinking could be wrong:

1. My new center valve block was not purchased from an official Land Rover site, so as touchy as these trucks are, that might something. It's correctly installed. I've brought LR valve diagrams out with me, and individually traced each connection the entire line length to its destination. I've done this multiple times. I know every aspect of the EAS under the rig by heart now.

2. My new compressor is not a genuine Hitachi although its made for the LR3. My old original Hitachi compressor as pointed out probably needs an exhaust job. Both of these could be causing the fault.

3. It could be the air suspension control module, or as mentioned the height selection switch.

4. Even though the system is not leaking any air, maybe the computer doesn't like something in the front or rear valves. I've cleaned them in and out and the GAP tool shows they're working fine but...

I've re-installed the firmware a bunch of times and re-calibrated the EAS at least 50 times without exaggeration.

As I said in the beginning of the thread it's not my way to just start throwing parts at problems however it seems that's where things are at even with the expert advice I've received. The best way would be to purchase all these parts at once and just start replacing things one at a time to see what does the trick, then return what's not needed. Truth is I can't afford to do this and don't have the time to spend ordering, waiting, returning, ordering again.

 

Honestly I think you're at a point where you've spent more trying to avoid costs than just going head in....
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I've already said what I would do.

 

going head in on what? The height selector switch? I’ve followed all your other advice; which has been greatly appreciated. As for costs I can return everything I’ve purchased.

 

I'm not sure specifically what I meant, to be honest, that was many beers deep. Looking at it the day after though, I do think that your faulty switch is veiling whatever the issue is. My hunch is that it will be easier to diagnose your EAS issues if problem numero uno is fixed; the switch.

When I've had the codes you describe, the EAS still works, if I recall correctly. So your biggest issue, really, is that darn switch.