Hi everyone,

In the winter (ie. below freezing temps), I would get an airmatic warning after driving for a minute. I got 2 codes for a system leak and the compressor taking too long to build pressure.

Now that it has warmed up, I went ahead and installed the replacement piston ring kit. I then put everything back together. I assumed this would help solve the building pressure code.


Here is where I believe I messed up. I have a Foxwell NT530 scanner that I wanted to use to test the system.

I used the scanner to raise the car up and lower it back down. I played with it for a bit. I should have left it alone.

I pulled the car out of the driveway and parked it. It was at its usual level then.


When I went to drive the car a bit later, the airmatic warning came on within seconds of starting the car. The code was for a system leak.

I pulled the car back in the driveway today and sprayed all the connections at the compressor and valve block. I assumed the leak must have been from where I was working on it.


There are no leaks at the compressor or valve block. Using the scanner, I cannot get any of the struts to move up and everything is now sitting low enough that I can't get the jack back out from under the car.

When the compressor runs using the scanner, it only runs for a few seconds and then shuts off. I cannot perform the 40 second system test. The scanner has the option, but nothing happens when I press start.


My question is what areas can I reasonably get to to check for this major leak? I assume that I blew something out when using the scanner to raise the vehicle.

I can spray the tops of the front struts and and the compressor and valve block easily enough. Not all corners were down this morning, but they are all down now.


I have also verified that the compressor is outputting air.



Thanks.

 

Your leak may be in a front strut or rear bag and not just one of the line connections. Is the car low at all four corners? What led you to repairing the piston rings? Raising a lowering the car would not have coaused a problem - it is designed to do that. But, if you had a problem it could have exacerbated the problem. But, you had the problem anyway.

 

I don't see how a leaky bag would drop all four corners, which it now has done. Doesn't the valve block separate the circuits?

I replaced the piston to correct the code for the time it takes to build pressure. Both codes only existed when the temp was below freezing. I figured that was due to something shrinking just enough to leak.

I've never had the automatic warning at temps above freezing.

 

Valve block failures are not uncommon. Don't buy aftermarket if you replace it.

 

So I figured I would give an update.

Using the scan tool to lift each corner individually only had the compressor run for a few seconds each time I hit the button. It wasn't enough to lift it.

What worked was hitting the option to move the vehicle to the calibrated position.

This moved the car all the way up where it should be.

Now that it is at height, I am still getting an intermittent code from the aromatic. Sometimes I drive it all around and it never pops up. Sometimes it's on within a minute of starting the car.

I was able to spray a lot of the airlines for the system and found no leak. The one spot I still need to check is the reservoirs and their hoses in the back. I can't even see them without getting all the way under the car.

I believe that even with the new piston, the compressor is just a little weak. I am not sure why I only got codes when it was cold before, but now they appear when it's warm.

I really wish I knew the parameters that the system is looking for to determine when to throw the leak code. I believe it might be reading both static pressure dropping, and the expected increase in pressure when the compressor turns on.

If the second is true, then a weak compressor would flag for a leak as it would not build the pressure that the system is looking for over the programmed time period.

Does anyone have knowledge of the code parameters?

At this point the car is up, and staying up. I might just put a new compressor on and be done with it. I also ordered some of the airline and fittings in case I do indeed find a leak.

 

How is everything going now? Everything good?

Edit: Thanks for the update.

 

Everything seems to be fine other than throwing a code. The car sits at the correct height and everything.

I previously had an issue where the left rear was always a bit lower, and that has been mostly corrected. I think the car dropping all the way down kind of reset the pressure in the back and leveled things out.

I'm still going to throw a new compressor in there. I also bought some line and fittings just in case I find a leak when I get it back apart to change the compressor.

The compressor to valve block line (short little black one) did have some bubbles at one point, but they went away when I tightened it a bit. I'll replace it to be sure.

I don't know why the codes are more present after I replaced the piston ring, but that's what I have now.

Will report back if new compressor solves one or both codes.

 

UPDATE:

New compressor is installed. I was able to source a genuine Wabco unit for a decent price.

No codes have popped up since the install. I have driven the car quite a bit.

I guess this is some amount of proof that a bad (weak?) compressor could throw a leak code as well. Or possibly there could have been some internal issue and air was bypassing through the compressor itself.