Factory Air Suspension Troubleshooting

[ForTehNguyen]

For the past couple weeks, I've been getting a "Service Air Suspension Immediately" warning in the first few minutes after startup which disappears in a few seconds. Theres no standing warning lights. Suspension is factory with no mods. Lately it has not let me move higher than Aero height, but it did lower to entry/exit (then wouldnt raise back up). I came back later and the height was back to aero. I pulled the air compressor fuse overnight to see if there was a leak. There was no change in ride height overnight.

I went out of town and no issues after several hours of driving. Then after parking and coming back several hours later the rear was noticeably lower. While driving, the rears were hitting the bump stops and had no dampening. Had to drive back home a couple hours with no rear dampening. Dash still displayed no standing warning lights and still aero height. Front suspension was fine going over speed bumps to test. Back home removing the rear wheels and liner and found the drivers side to have no pressure, while the passenger side still felt firm. Sprayed soapy water everywhere on the folds on both bags underneath the dust cover (where most leaks tend to occur), compressor fittings, accumulator fittings, bag fittings, and could not locate a leak. Compressor still runs and sounds normal and cuts off after a lengthened runtime.

Is it safe to conclude from this that the rear bag is bad and also since 3 of 4 bags are good that the compressor is good?

 

[ForTehNguyen]

wanted to update this thread. Air suspension seems repaired. Since only the drivers rear corner was deflated that points to that bag being the main culprit. Otherwise if something more common like the accumulator was leaking, all 4 bags wouldve sagged. Plenty of videos online how to remove the rear bags even from the previous Ram gen. Bags are similar. I borrowed a nitrogen tank, regulator, AC manifold/gauges, and R134 quick connectors to fill the system to 175 psi. It helps to thread in the air connection before pushing hte top of the strut into the mounting holds. When filling a new rear bag for the first time make sure the top clips are seated and the bottom perch is close to being seated. Will have to jack up the rear axle for this to close the distance some. That way when you do the initial short fill it will seat correctly. If the air bag doesnt seat correctly, it will extend, jump out, and get all crooked. You'll have a big issue because the way the bag underneath the dust cover is folded and rolled will get out of whack and its a PITA to get it back where it needs to be. Dont skimp on this seating step.

Once the rear bag is installed, connect with AlfaOBD, security bypass dongle, and go to the suspension drop down to find the air suspension module and connect to it. From here you can read various faults and activate procedures. Perform a compressor function test, height sensor test in alfaOBD to verify those are good and clear any existing faults too. Pick the corner you just swapped out and do a short fill. It will add air to the strut, extend it, and if you followed the steps previously it should seat and perch on the axle straight. Jack up the rear axle some more to get some load on the bags. Now perform a full fill on that new strut. For the other bags do short fill and full fills as well to top those off. Try to get the truck around aero/normal height. With all of these filled the accumulator will have lost some pressure, refill it back to 175 psig. Now test everything by going through all height settings. Do not try to fill the system to 175psi when in off road 1 or 2. When it lowers to aero/normal it will be overpressured to 200psi or so. I heard the pressure relief go off when lowering back to aero normal after i filled to 175 psi at offroad 2.

You can do other things in AlfaOBD like get the system mass and pressures to keep an eye on occasionally. I'll be checking on strut and reservoir pressures during the week before calling it good. If you get a Service Air Suspension Warning message, definately use AlfaODB to find the fault. I was getting the message for 2 weeks, but didnt notice any difference in height. The compressor would run occasionally to level it until it ran out of accumulator pressure from the leaking bag.