With that statement, I think you might be on to the problem and hence the solution.

Do you have the Nav display that shows a 4x4 page showing the disposition of the individual wheels - that is which way the front two are steering and how the wheel centres are vertically located relative to some given common position?

If so, find a quiet spot where you can force each wheel one at a time, to lift up and sit on top of something like a curb about six to eight inches high. If your display is working, probably three of the four wheels will show an appropriate vertical movement. If only two wheels show movement, I would anticipate they would be either the front two or rear two.

Regardless, you now have a hint as to where the problem is. If only one wheel fails to move, then the problem is probably either a height sensor or the wiring to it. If two wheels, then it is perhaps a block valve. Something else might also happen such as the extended thing but if so, it may be triggered by one particular wheel and if that can be determined ....

Re block valves, the front is relatively easy to replace, the rear, near impossible to get at an hence no fun at all.

Let us know as to the 4x4 display results if you have that.

In the meantime, I will keep thinking about other related possibilities.

Make certain you have the frame blocked up with axle jacks as you are playing with the air system and all three tons can drop near instantly. If you do not have any spare hands or fingers, it matters.

 

Hi,

I have tried what you suggested and got some puzzling results. If I put both right tires, front and back on the curb the 4x4 display looks level. Same result when I put both left tires up, both front tires up and both rear tires up. The it gets downright confusing. If I put the front right tire up the display shows that the front right and rear left tires are up and the other two down (cross articulation?) this is the same result with all the tires if I put only one up the opposite tire on a diagonal also appears higher.

I do have a Carsoft i903 scanner that reads suspention codes and there has only been the one code C1A13 Pressure does not vent gallery. I haven't seen any other codes that would indicate a height sensor being bad, although I replaced the DR side rear height sensor last year based on a scan the stealer did before I bought my own scanner.

I have also inspected the wiring under the front DR side wheel well as I have read on other posts that broken connections here going to or from the compressor can cause this problem.

 

The results you got are pretty much what I would expect, hence I think the height sensors and wiring to are OK. I guess that is good news but it does not solve the problem.

The air suspension system is just that, and not a vehicle leveling system. When you have the two front, two rear, or both left or right side wheels high, the 3 just thinks it is parked on sloping ground, be it a hill or a side slope.

In other words, the suspension does not try to make the vehicle body level.

The purpose of any suspension system is to keep a vehicle from bouncing around - that is remain on a given plane, but not to keep a martini from pouring out of the glass in the case of a FF Range Rover, when sitting on the folding table in the rear and the vehicle is on a significant side slope or going up a hill.

When, for example, the left front wheel sits on a curb, that means the top of the respective tyre is closer to the top of the wheel well. The compression of the air spring will transfer a load to the right rear and tend to make the top of the left rear tyre sit closer to the top of the left rear wheel well. The tyre did not move, (the body did), but as measured by the wheel height sensor, it appears the rear wheel has raised as well. You also get an apparent movement of the other two diagonal wheels in the opposite direction.

So we are back to the original problem - why when you actuate the centre console rocker switch to lower the vehicle, it instead rises.

Question - if you move the rocker switch to tell the 3 to raise to off road height, does it? I expect it does but I do wonder.

The vehicle is new to you and I presume you have not dumped a cup of coffee into the switch? Yes, the previous owner could have but that is not something you would know. I also presume that the down did work for a while after you purchased the 3?

I guess I am wondering if you have a defective up down switch For an off road go anywhere vehicle - well to the shop certainly anyway - that switch is not McDonalds takeout proof.

The theory of the "extend to off road or more" feature is that if the 3 detects it is bottoming on high ground at any height or when lowering, it will automatically raise to an extended height to clear the sensed obstruction. Your 3 would appear to think it is hitting something when the down switch is activated. I guess another question is do you think your 3 drops a bit before it does the rise thing? That will be hard to determine, but I wondered. If not, but instead the 3 just goes high, that might suggest the switch being a problem.

Does your code tool have a feature related to adjusting the individual height sensors? While there is an argument to say that changing out a single height sensor does not require the full recalibration of all four sensors, I have always wondered about the supposed self calibration capability of the air system computer for a single height sensor.

 

Hi,thanks for the info. Gonna try to awnser them in order . I have owned the lr3for 7 years and have only had problems recently and only with the compressor. This is the 4th one in the last year. Havent had a spill on theswitch yet(knock on wood) and the scan tool i have doesn't throw any errorsrelated to the switch. The lr3 will go up fine its when i lower that ihave problems. It will start to lower and then Either it will go into extendedmode or throw the C1A13 error and the amber light will go on stopping anyheight adjustments. I am out of ideas.... Any help will be appreciated. My mech told me that it could be the air dryer which would really botherme as this is a brand new doorman compressor.

Ohand the icarsofti930 will tell me the height if each wheels relative positionin mm but it does not have the ability to program in new heights or resetheights. Hope i got it all in there.

Thanks in advance for the help!

 

Seems to me that if you've changed the compressor THREE times in the past year then you have another issue. Could be a calibration issue. Have you looked at the calibration?

I'm not familiar with the Doorman compressor but I'd want an AMK.

 

The reason that I went with a replacement Doorman compressor (same as original Hitachi compressor) was so I could avoid having to do the software update at the stealers that is required with the AMK compressor. This one is supposed to be pug and play. Scanning the LR3 only gives me one DTS code C1A13 Pressure does not decrease when venting gallery. if I can get to the root of that problem I will be sailing. any thoughts outside of calibration or installing an AMK?


I have verified that the Exhaust valve is good, looked at the wiring under front left wheel well, disconnected the air line going to the silencer so as to eliminate that whole section rear of the compressor and those lines/silencer is not the issue. ( I get the same code when LR3 is venting to atmosphere) I am running out of ideas that are not the compressor. when I clear the codes the compressor will run fine. I can go up but when I try to go down It starts to lower then goes into extended mode followed by amber warning and C1A13 code.

 

I am not certain I am going to be much help. I would regard the Dorman compressor is an OK replacement as my understanding is that the AMK has its problems as well. Basically on one can build a reliable long life single stage plus 200 psig air cooled compressor - 150 psig, routine, but 200, that is one bridge too far. I would think that the Dorman would come with new crystals in the air dryer so it should be OK.

I presume the switch is OK as well - that would have been an easy fix.

I guess what you have is a good Land Rover friendly code reader rather than a software installer like the BlackBox or GAP.

Three new compressors in a short period of time suggests a not compressor problem by the way. Off hand, was there any common problem with the discarded compressors? I am thinking one of the height sensors is faulty and giving the computers a funny message that suggests the 3 is bottoming or there is an air discharge problem - either way wrong, but something is making the computers think either may be the problem.

What was the reason for the replacement of the one height sensor. I am wondering if it is defective or the wrong one in the wrong location. The sensors tend to work backwards on one side - bigger numbers mean the same as smaller numbers to the computers depending upon location so a wrong sensor in the wrong place has repercussions.

Anyway, what was the order of the compressor replacement relative to trouble messages etc?

I would guess that if this is the first real problem with your suspension system in the 7 years you have had the 3, that is pretty good. My troubles were when new, or about year four/five after the warranty was over. One free compressor on warranty and one Hitachi I had to pay for. I have over time put four new sensors in just as a maintenance thing. The sensors do wear and start to send spurious signals to the computers just due to old age.

 

I'm on the same page as bbyer. It's not the compressor. If you had the GAP IIDTool you could re-calibrate the sensors.

@bbyer what is the issue with the AMK? Recall that there are two generations of AMK compressors, and I read that the 2nd one was pretty solid. Not sure. I guess I'm hoping!

 

Here is the advice that was posted on here by Volkov July 2013

Ok the schematic I am looking at, has the pilot exhaust solenoid as part of the compressor. If I understand the system right, that is the only place that it vents from. It is located between the dryer and the compressor, so that everytime the system vents, moisture trapped in the dryer is blown out, at least thats the theory.

PILOT EXHAUST VALVE
"A solenoid-operated pilot exhaust valve is connected to the air delivery gallery, downstream of the air dryer. When the solenoid is energized, the pilot valve opens and pilot air moves the main compressor exhaust valve plunger to deflate the air springs as required. Pressurized air from the air springs and/or reservoir passes through the reservoir control valve to the air supply unit. The solenoid has a resistance value of 4 ohms at a temperature of 20 degrees C (68 F)"

EXHAUST VALVE
"The exhaust valve has three functions. It operates in conjunction with the pilot exhaust valve to allow air to be exhausted from the air springs and/or the reservoir as described previously. The valve also protects the system from over-pressure, since it is connected into the main pressure gallery which is always subject to the system pressure available in either the air springs or the reservoir. The valve restricts the maximum operating pressure to between 333.5 and 370 lbf/in2 (23.0 to 25.5 bar)"

Now I should point out that this is talking about the Hitachi compressor, and I am not sure how different the AMK is, but what I would do is try to find the exhaust solenoid on the compressor, and test resistance across it to see if it is open or gives you a value of 4 ohms.

So I guess off I go to test the pilot exhaust solenoid on the compressor, and test resistance across it seeing as I cannot re-calibrate the sensors with my scan tool.

This LR3 is really testing my patience.

 

As best I can figure, the pilot exhaust valve is run by an electric solenoid, the kind of "gold" round bit with the blue and white wires running into it per the jpg below and the wiring diagram.

Air or the lack of it exiting the pilot operates the main exhaust valve which is mechanical - spring loaded so to speak and is also the system over pressure valve should something go wrong. Per the jpg, these two valves are hidden inside the main compressor unit so to speak.

As with houm_wa, I suspect the valves are all OK given your compressor is rebuilt new so to speak and that the problem is one or more of the height sensors.

Yes, these air systems can be tedious. I also find that for some reason, the 3 has the ability or cover up or gloss over a singular problem, hence when things stop, there is more than one problem to fix before all is well again. What this means is that just finding and fixing a problem in one area still leaves you with the 3 not working. In other words, once it stops, then everything has to be fixed or it just will not go. This is probably why I routinely replace alot of stuff before it goes - fear, and I admit it is easier to just give in.

Let us know if you have any success measuring the coil resistance. I regard coil resistance measuring as not always straight foreward - something about imaginary resistance like a capacitor as opposed to the kind you measure from a resistor.