Possible air suspension issue

[G1212]

Hey all,

I’ve got a 2019 Limited with air suspension, and I’m experiencing some strange behavior with the compressor. If the truck sits for a week or so, the compressor runs for a good few minutes on startup, and I often get a warning saying the suspension system is unavailable until it cools down.

I also hear a pressure release hiss after the compressor runs for a long time, and sometimes even while driving. Despite this, the truck never seems to drop in height, no matter how long it sits.

I’ve also noticed the compressor running briefly (10-20 seconds) after I’ve driven it and jump out of the truck, but this only happens rarely.

I ran a scan and found these older stored faults (no active faults though):

• C1562 92: Ride height air pump control circuit - Incorrect performance/operation
• C1561 97: Valve assembly - Component/system operation obstructed or blocked
• C1540 01: Height control solenoid valve rear left solenoid valve circuit - General electrical fault

Other than the compressor running like that, the suspension seems to rise and lower fine, and the ride feels normal. Has anyone experienced anything similar or have any advice on what to check next? Or am I reading too much in to it?

Thanks!

 

[1BADRAMLIMITED]

I'm not for sure if it's an issue to dive deeper into but personally if I sit the truck for a long-extended period of time I drop it to entry exit do mitigate any issues with the compressor trying to keep the bags inflated over that time

 

[G1212]

Having driven it today I would say the venting sound is happening more often, In a 15min drive I noticed it twice

 

[GSD222]

Just based on the codes maybe check the ride height sensors starting with the rear left. Sometimes the connections get dirty and malfunction. You can check their function using a multi-meter, which you can see in the following video around 8:15ish:

Next it might be worth checking for a leak using a spray bottle of soapy water. Check the connection ports in the air ride compressor (the top one can be tricky to see and runs to the reservoir tank so make sure on that one, I had a leak for months because I missed it), the fill ports and tanks, and the connection points at each of the air shocks. The plastic elbows on the front air shocks have been known to go bad from time to time and are a cheap and easy fix.

If you get to the point where your truck starts dropping and you think it might be a leak in one of the air bags, disconnect your battery overnight and see which bag lost the air when you go out to your truck the next morning.

If you've considered AlfaOBD before, it might be a good time to purchase it as there are several diagnostic tests you can run in the program as well.

 

[Damien64]

2024 Limited with air suspension
Every time I unlock the door the compressor turns on and I can see the truck leveling out. Is this normal?

 

[kapinallinen2]

2024 Limited with air suspension
Every time I unlock the door the compressor turns on and I can see the truck leveling out. Is this normal?

If it is just a minor correction in height, lasting few seconds, then most likely.
My truck does this but not every time when I unlock it.

 

[Damien64]

thanks

 

[jeep12joe]

I get the pressure release hiss occasionally also, which has always been odd to me since this is supposed to be a closed system.

 

[My1stHemi]

I’ve never had issues with my air suspension but in the last few thousand miles( now around 76k) mine has pumped and hissed a few times. I removed the cover at the valve manifold and snugged the outlet lines. No bubbles with a soap test but haven’t had any issues since.
The pump/manifold seemed a little wobbly so I stuck a piece of foam between the frame and the unit to avoid too much movement.

I’m curious if there is a way to top off the nitrogen in the system.(?)

Fingers crossed but I have no regrets since this is the best riding truck I have ever been in, and for a half ton, it handles large trailers like a champ.

 

[CaptainCJ35]

I’ve never had issues with my air suspension but in the last few thousand miles( now around 76k) mine has pumped and hissed a few times. I removed the cover at the valve manifold and snugged the outlet lines. No bubbles with a soap test but haven’t had any issues since.
The pump/manifold seemed a little wobbly so I stuck a piece of foam between the frame and the unit to avoid too much movement.

I’m curious if there is a way to top off the nitrogen in the system.(?)

Fingers crossed but I have no regrets since this is the best riding truck I have ever been in, and for a half ton, it handles large trailers like a champ.

I'm getting this too... 74K miles. It generally happens after a cold start, pump runs and runs until there's a whoosh, like a pressure valve released. If it is a valve releasing... where's it going?

I've had it looked at and I'm told there are no codes and gas pressure is normal. I'm not sure what the next step is, but this isn't "normal" and I'm worried that it's going to fail at the worst possible time.

 

[My1stHemi]

I'm getting this too... 74K miles. It generally happens after a cold start, pump runs and runs until there's a whoosh, like a pressure valve released. If it is a valve releasing... where's it going?

I've had it looked at and I'm told there are no codes and gas pressure is normal. I'm not sure what the next step is, but this isn't "normal" and I'm worried that it's going to fail at the worst possible time.

Right. If a sealed system is regularly venting to atmosphere and not being recharged, at some point we will run low on the charge.

I too was worried about an inopportune suspension fault, like this summer when I was towing a travel trailer.

What I haven’t found is a PRV.

Worst case, it would be nice to know if there is a schrader valve where I could add a shot of compressed air if my system was low on nitrogen and was causing a fault. I’d rather contaminate the system with air and later have the system purged rather than be stranded.

 

[My1stHemi]

Reading on the DS platform forum, they have had some success purging and recharging the system, some using UV dye to check for leaks(smart). Their system, and I would imagine ours, will pull atmospheric gas to makeup for lost nitrogen. The problem is the moisture that introduces….

Air suspension recharging ideas

 

[kapinallinen2]

Right. If a sealed system is regularly venting to atmosphere and not being recharged, at some point we will run low on the charge.

I too was worried about an inopportune suspension fault, like this summer when I was towing a travel trailer.

What I haven’t found is a PRV.

Worst case, it would be nice to know if there is a schrader valve where I could add a shot of compressed air if my system was low on nitrogen and was causing a fault. I’d rather contaminate the system with air and later have the system purged rather than be stranded.

You can use the low side hose from a R134 service kit for charging the system. Alldatadiy has the step by step air suspension service procedure.

I put this together for using with a nitrogen bottle. No need for the regulator if just using 120 psi shop air to get it off the bump-stops.

 

[CaptainCJ35]

Right. If a sealed system is regularly venting to atmosphere and not being recharged, at some point we will run low on the charge.

I too was worried about an inopportune suspension fault, like this summer when I was towing a travel trailer.

What I haven’t found is a PRV.

Worst case, it would be nice to know if there is a schrader valve where I could add a shot of compressed air if my system was low on nitrogen and was causing a fault. I’d rather contaminate the system with air and later have the system purged rather than be stranded.

I'm worried the system is already getting contaminated. Yes, it could be venting out... but it could also be sucking in, right? If the pressure differential that is building up is a vacuum, then that woosh could be air going in somewhere. I don't know enough, and any schematics I've seen show that's likely not possible. Is the woosh going from one tank to the other?

Having the dealer take another look tomorrow. It happening more frequently.

 

[CaptainCJ35]

Dealer is saying the compressor/regulator is failing and needs to be replaced. They weren't able to answer a lot of questions I had, so it didn't inspire confidence and want $2300 to get it done... which is preposterous. Air Delete here we come.

 

[My1stHemi]

Dealer is saying the compressor/regulator is failing and needs to be replaced. They weren't able to answer a lot of questions I had, so it didn't inspire confidence and want $2300 to get it done... which is preposterous. Air Delete here we come.

So sad. “Parts cannon” operators disguised as technicians.

There’s zero incentive for them to resolve the underlying issue. They clearly don’t know why the problem exists and what causes the failure.

I had a similar experience under warranty with my driveline “bump stop”. It’s a driveshaft issue, and I told the dealer to inspect that. Instead, they replaced the transmission. Problem still persists to this day.

 

[G1212]

Thought I’d give an update on where I’m at, or at least where I think I’m at so far. I did a leak test, set it to go at the end of day on a Friday, and checked it on Monday morning. The only changes I noticed were:


• Air tank component air mass: dropped from 75 bar per litre to 63 bar per litre (a 12 bar per litre drop).


• Total system air mass: dropped from 166 bar per litre to 155 bar per litre (an 11 bar per litre drop).


• Air tank reservoir pressure: dropped from 6 bar to 5 bar.





Other than those drops, all pressures stayed the same, although I did notice a 2mm rise on the front and a 3mm rise on the back. I put that down to temperature changes, though.





I’ve since checked the compressor, which did seem to have a little excess movement, so I padded that out. I sprayed everywhere with soapy water and couldn’t see any bubbles, but the connections with a nut on them did tighten by maybe half a turn. I tried to tighten the connections to the tanks themselves but was struggling a little to get in there from the floor.





I then carried out another leak test, but only had time to run it for about 6 hours this time. There were no changes to any of the pressures, but I did notice a 1mm drop on the front left. At this point, I felt pretty smug. I left the truck to sit over the weekend and started it up today. The compressor ran for maybe 30 seconds before the dreaded hiss. Driving it, I noticed the hiss again, but it’s definitely less frequent.





So, my current thinking (and hoping) is that I’m on to something and just need to try tightening the connections to the tank. Otherwise, I’ll need to do some more investigating—unless the thing puts me in an early grave with all my stressing!

 

[My1stHemi]

Thought I’d give an update on where I’m at, or at least where I think I’m at so far. I did a leak test, set it to go at the end of day on a Friday, and checked it on Monday morning. The only changes I noticed were:


• Air tank component air mass: dropped from 75 bar per litre to 63 bar per litre (a 12 bar per litre drop).


• Total system air mass: dropped from 166 bar per litre to 155 bar per litre (an 11 bar per litre drop).


• Air tank reservoir pressure: dropped from 6 bar to 5 bar.





Other than those drops, all pressures stayed the same, although I did notice a 2mm rise on the front and a 3mm rise on the back. I put that down to temperature changes, though.





I’ve since checked the compressor, which did seem to have a little excess movement, so I padded that out. I sprayed everywhere with soapy water and couldn’t see any bubbles, but the connections with a nut on them did tighten by maybe half a turn. I tried to tighten the connections to the tanks themselves but was struggling a little to get in there from the floor.





I then carried out another leak test, but only had time to run it for about 6 hours this time. There were no changes to any of the pressures, but I did notice a 1mm drop on the front left. At this point, I felt pretty smug. I left the truck to sit over the weekend and started it up today. The compressor ran for maybe 30 seconds before the dreaded hiss. Driving it, I noticed the hiss again, but it’s definitely less frequent.





So, my current thinking (and hoping) is that I’m on to something and just need to try tightening the connections to the tank. Otherwise, I’ll need to do some more investigating—unless the thing puts me in an early grave with all my stressing!

Are you using alpha obd to read a bcm module that spits out those values?

 

[G1212]

that was using a texa system but they have some kind of agreement with stellantis to allow the gateway to be unlocked

 

[My1stHemi]

I’m curious to hear comments from converts of air springs to coil springs on the difference in ride quality, laden and unladen. Please share.