nj450gl

Wife’s car, 2013 gl450 with only 80,000 miles. Changed the rear bags to Arnott two years ago and they are fine. The vehicle does not seem to leak air, it runs level and normal height. It does run a little bumpy, maybe warmer temps increasing tire pressure????? I did notice a month ago when I tried to raise the vehicle for an oil change that it was rising extremely slow. Today, my wife got a suspension malfunction warning on the dash after going over. A speed bump. Again the truck seemed level and drove normal if not a little bumpy side. So when she got home I pressed “ok” on the steering wheel button and the error went away. Next, I tried to raise the vehicle, if it was lifting, it was super slow. Any guesses? Bad compressor? Block? Fuse? There may be a front strut leak, but it never sags after sitting for days, so I don’t think so.

Mikey178

Based on the description, I hate to say it but you will have to scan it to see what codes you are getting related to the airmatic suspension to start to figure out what is wrong.

nj450gl

Just scanned it

Mikey178

I just went through replacing my valve block and compressor. I was getting the same error codes C156C00, C156B00 & C155664 specifically.

When I started experiencing the airmatic malfunction light about 4 months ago, it didn't raise, ride felt bumpy, the ride height seemed a bit lower but never sagged. I would notice when I started the vehicle the compressor would run for a long period and then shut off, drive for a bit and I would get the error on the dash. When I checked with Xentry the compressor was running too long and going into overheat protection. I'd have to wait until it got to 50% value (assume temp) and when you restart the vehicle the compressor would start again and repeat until the malfunction light came on. Also, did a compressor test in Xentry which was showing the compressor was not able to build enough pressure (I believe it was 14 or 15 psi required and mine was only building about 6 psi).

I had replaced rear airbags with Arnott about 1 year ago due to sagging issues (confirmed leaky air bags via soap test) but had the sagging for about 8 months prior. I believe with the prolonged delay in fixing (Yes, my own fault) I may have inadvertantly let the compressor overwork.

About 3 months ago based on research I replaced the valve block but that did not help and finally about 1 month ago replaced the compressor (Arnott - ARN-P3258) as well as the relay which comes with the the compressor from FCP. Since then the airmatic system has returned to normal function and no longer have any issues or error codes.

Check all air lines for leaks, spray with soapy water as a first step, check the valve block for any leaks, if no leaks, I would suggest go with compressor replacement with relay and also change the air filter for the compressor while your there (Mann MAN-WK327) also from FCP.

nj450gl

Thanks for the reply, ordered the compressor. Gonna get a visual and spray with soapy water. From what I understand it's the tank part of the compressor that usually fails, if it's cracked, then it needs to be replaced, if its the connection i might try to reseal with rtv.

Mikey178

Yes, the tank or the relief valve is what I've researched fails. I actually saved my old compressor to one day do a rebuild when I have nothing to do

Let us know how it goes and good luck

Javi's GL 350

Check the Air Suspension Solenoid Valve

Panzerknacker

We had similar symptoms and it was the valve block and compressor. The car would never sag but the valve block was sticking and the compressor was struggling to raise the car. Taking forever to raise and “Compressor Cooling” on the dash.
Thank goodness for aftermarket warranty.

nj450gl

rebuilt oem compressor and new air filter from FCP Euro for $500, easy fix, works great. The compressor always ran, but was extermely slow raising the vehicle, the old filter was very dirty, wonder if a filter only change would have down the trick. For those of you who have not done so, changing the compessor air filter is worth the effort and costs less than $10.