OK excellent thank you for that. Does that solenoid shut the motor off if the gallery pressure does not rise fast enough? What would cause this motor to turn off after four seconds?

 

No.

The only thing that controls the compressor is the suspension ECU. There are no hard interlocks.

The gallery is simply the collection of pipes and other OPEN areas between the compressor piston head and one of the solids on the rear block and the front block. Essentially the "working space" of compressor. If the front needs to raise, for example, the front valve block opens up to the gallery to receive air. Needs to lower? Same, but with compressor off, exhaust open (on compressor itself) and reservoir closed.

When needing to raise the system works by firing up the compressor assuming there are no hard faults such as broken height sensor or disconnected pressure sensor. the compressor runs momentarily to bring up gallery pressure to about 150psi and will do so with the assistance of the reservoir by opening it up also so it can feed the gallery with air - reservoir max PSI is 250 -while also opening, lets say, a front valve to raise one or both struts. If there is no air in the reservoir it will stay open but there is no "boost" in the raising and the truck will raise a little slower and take longer. Once the ruck reaches proper height the font and read valve blocks are closed off the gallery BUT like I said the reservoir is still open, so the compressor running is simply to fill the reservoir which the system "infers" is being successful by reaching over 200psi, usually closer to 250. Once reach, reservoir is closed off to gallery so the air can be stored/used next time. But the gallery pressure will drop by design. The gallery pressure MUSt drop because there is no way the compressor can fight that much pressure and start up again. this is also why a working system will "fart" before running and even after running, to vent off excess gallery pressure.

So... again run codes. Because you are not getting any had faults it looks like, you are getting some sorta performance fault for it to come up within seconds. That can be too many amps being drawn, low truck voltage, pressure not increasing (leak in gallery area or even bad compressor). The system infers faults based on data, like when a strut leaks. The ECU has NO way to monitor struts but if it keeps having to fill a low corner, it will generate an fault which it infers to be a leaking strut (too many transitions).

So not sure all that helps, but that is the system in a nutshell.

 

That is a brilliant reply. But what happens is I turn the key on and the compressor works for four seconds with the original compressor the other compressor works for about 15 seconds before shutting off the max gallery pressure. I saw yesterday was about 18 and it sits idly at 13.6 psi or whatever was in that photograph I shared. While reading the monitor, it showed the pressure go up and then as soon as the pump shut off the pressure dropped back down the six or so pounds that it increased.
So it’s the main computer the brain that controls the ride height that is shutting off the compressor and not one of the sensors I showed her the photograph above?

 

Both can have the same cause. Both could be exceeding operation power excess, too may amps. Both cold be "pressure increasing too slowly". Just that one is performing better than the other. Really need codes. Best to clear all codes and start with a fresh batch. Both of this pressures are stupid low, practically within margin of error for the sensor. And yes, when the compressor goes off pressure will drop by design, the gallery it not air tight, it is not suppose to be really.

Also, if not covered, I will add that there are two compressor "styles". One is Hitachi and other is AMK. Both have aftermarket copies. No matter who makes them, each style looks like the original from Hitachi or AMK - but the Hitachi style looks nothing like the AMK style and you can not swap styles without making a software change in the truck. So if both of yours looks the same, you should be okay. If they do not, that could be an issue too.

If I had to guess you either have two crap compressors OR you have a pretty big leak. OR both even have stuck open exhaust ports on the compressor, so it is just bleeding strait out. Keep I mind you can cap off lines for testing. You just need some sorta 6mm or 1/4 push connect cap that you can remove. So you could, for example, cap the output from the compressor and see just how fast pressure builds. If it is slow, the compressor is probably the issue if fast, probably a leak after that point. If you do this, Jack up the truck a bit because it will drop like a rock when it opens front or rear valve blocks expecting air to come in and none does.

 

I feel it Hass to be something simpler. The pump runs for about two seconds and then you can feel it bearing down and starting to bring up the pressure and then it just shuts off as if told to shut off there’s no time for the gallery or an empty tank to even build a few inches of pressure. The suspension is flat on its feet right now the rear truck first and then a few weeks later, after not running it the front finally dropped and the compressor s are identical.

But I’m gonna read both of those messages over a couple of times and try to narrow things down.

Those codes I showed yesterday were after a full reset. And there’s only two.

 

Then your own code is pressure increases too slowly. That means a leak in the gallery or the compressor has an internal leak at the piston or exhaust port. That is all there is to it. At this point I guarantee the reservoir is empty. If you want to get creative, you can add an air input to the system after disconnecting the output line at the dryer. Then you can use a shop compressor to build pressure in the gallery and look for leaks, etc. If you had a GAP too, you could even air up the system off an alternative air supply. Unless your tool can also control the valve blocks to open up or not.

 

Argh. I’ve now got these codes as well. I got C113192 this morning, then cleared it and gallery built pressure from 150 to 250 psi with no problem. Then drove 360 miles to a work site for the afternoon. Upon leaving I got C1A2064. However this time the gallery pressure was about 245 psi when the pump cut out after running for 4 seconds. Clear the code then pressure built very slowly to 255 psi before the C1A120 came back.

Drove to the hotel, parked, restarted the engine (no more suspension fault light) and the pump ran for 20 seconds before turning off with no faults.

I got one of these codes a few months back and I attributed it to low battery current because I was running the heated windshield, seats, and steering wheel. This time none of that stuff was on, but it was again about 30 degrees. Either the compressor does need to be rebuilt, or maybe I have some water freezing in a line. Compressor was rebuilt 2-3 years ago and dryer replaced 1 year ago.

 

I installed that original motor with the new dryer installed. I cleared all the codes. I did a running start and that friggin pump turned on and stayed on and lifted that back and all went to 4 x 4 height but it didn’t move the front end even after driving. But while driving it dropped back down to normal right height the front and didn’t move so I’m changing out the front junction block with the sensor eight or 10 pins anyway it’s getting a brand new one tomorrow that is off of another rover own but maybe not new.

I’ve convinced the guy to never buy off brand on British stuff…

we will see how it works after changing it.

 

OK, erase the codes and started it up the back and raised the pump works for as long as it needed to the front end does not raise and the ride control light turns orange on the dash and the front and will not come up. We change the front junction block, I removed the cheap Amazon 50 dollar unit a few minutes ago and replaced it with the original one out of it. And nothing changed. So it could be that both are bad maybe?
The following is a set of pictures showing the codes after reset, and there are no discernible air leaks

 

Or they are plumbed wrong, would not be the first time. Also make sure the connector is clipped on ALL the way. The weather seal can bind up and you think its on when a good tug will take the connector right down.