Air Suspension Issues

[AH64ID]

to the best of my knowledge the system is a closed loop and the bags bleed off to a tank the compressor fills from the same tank. if the tank pressure is low you will get a fault.

Only the 1500’s are closed systems. My 3500 is very much an open system.

 

[DonFitzwater]

Only the 1500’s are closed systems. My 3500 is very much an open system.

If I’m not mistaken, the 2500 rear air is a unique system and is closed. Maybe someone with access to the system info can share.

 

[AH64ID]

If I’m not mistaken, the 2500 rear air is a unique system and is closed. Maybe someone with access to the system info can share.

Would be nice to verify, I understood they work like the 3500. @Ltngdrvr should be able to help us out.

 

[Ltngdrvr]

AFAIK, the 2500 uses a closed system, but it definitely has a compressor, and it also uses a nitrogen charge.
I have yet to see a full explanation of how the system works.
And luckily, so far, I have not had to get into mine for any repairs.

 

[AH64ID]

AFAIK, the 2500 uses a closed system, but it definitely has a compressor, and it also uses a nitrogen charge.
I have yet to see a full explanation of how the system works.
And luckily, so far, I have not had to get into mine for any repairs.

Interesting. So you don’t have a air intake/exhaust for the compressor between the cab and bed behind the rear passenger door?

The 3500 does a purge thru this port at every start, and dumps the air there every time it lowers.

 

[Ltngdrvr]

Interesting. So you don’t have a air intake/exhaust for the compressor between the cab and bed behind the rear passenger door?

The 3500 does a purge thru this port at every start, and dumps the air there every time it lowers.

Don't know, as I said, I haven't had to get into mine for any repairs.
And, I've never heard mine purge any air, even when I hook or unhook a trailer and the suspension resets itself.
The 3500, AFAIK has the same type of compressor and reservoir as the 2500 though.
And, this TSB> https://static.nhtsa.gov/odi/tsbs/2015/MC-10160041-9999.pdf describes the system as using nitrogen when replacing the compressor, and applies to both 2500 and 3500.

 

[AH64ID]

Yes they both use nitrogen in a service, but that doesn’t mean they are closed. Nitrogen is generally cleaner and drier, therefore it’s the preferred service gas.

Here is a test/experiment I did in September. Very much an open system.

Played a little more with this dead horse today

I have a pallet of heating pellets in the bed, 1 ton, and stood on the passenger side and actuated the NORM/ALT button with the key on and the engine off.

When I would turn ALT on it would purge air from the intake/exhasut line between the bed and cab on the pass side.

When I would turn ALT off it would fill the bags but not run the pump.

I did this 10 times and the pump didn't run once.

After 10 times the dash said battery low, start engine to adjust suspension height. So I am thinking the truck won't run the compressor if the engine is off since it always tops the tank off immediately after increasing ride height with the engine running and didn't today with the engine off. I can't complain about 10 cycles from just the tank air.

So there it is, again.... no doubts about an open system on the 3500.

We need somebody on here with a 2500 to tell us how it works.

So, does your 2500 have the hose between the cab and bed?

 

[jetmechabq]

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[EZeis]

Did we just have this debate??
My 18 3500 is 100% open compressor system. It purges air at every start up. It purges air when the truck is lowered. The compressor runs as needed. This stuff is pretty quiet and most don't realize it till they start paying attention to it. If it had any nitrogen in it, it was gone the first week I had the truck. That said, my truck is not a closed system and does not have a nitrogen supply. Which is good cause that nitrogen would eventually leak out over time and have to be reolaced. Not as fast as compressed air, but would still leak through the rubber bags just like a tire does. Nitrogen molecules are larger than atmospheric air. So it doesn't leak through rubber as fast. It also isn't effected by temperature or altitude like compressed air.

Earl

 

[jetmechabq]

this would seam closed loop to the tank

 

[AH64ID]

this would seam closed loop to the tank

It has an air hose just like the 3500. The 3500 also only has one hose from the pump to the tank. All the valves are located with the pump, no need for more than one.

 

[Ltngdrvr]

This says it isn't a closed system> http://read.uberflip.com/i/548478-issue-89/18

 

[dieselshadow]

My ‘18 3500 definitely does NOT purge on every startup. The system works fine and does as advertised. Once loaded up, I’ve heard the compressor run and I’ve also heard it making changes. I have yet to hear a purge upon startup. Just sayin’....

 

[AH64ID]

My ‘18 3500 definitely does NOT purge on every startup. The system works fine and does as advertised. Once loaded up, I’ve heard the compressor run and I’ve also heard it making changes. I have yet to hear a purge upon startup. Just sayin’....

My dad would make the same claim, but I hear it every time I drive his truck

He also says he’s never seen his CTS2 show a regen, yet I’ve seen it at least twice on his truck.

Just sayin as well.

 

[EZeis]

My ‘18 3500 definitely does NOT purge on every startup. The system works fine and does as advertised. Once loaded up, I’ve heard the compressor run and I’ve also heard it making changes. I have yet to hear a purge upon startup. Just sayin’....

It does, you just haven't noticed. Start the truck and stand between the passenger rear wheel and the cab. About 10 to 20 seconds after the engine starts it will purge. Give it a try. I never timed it, but it will do it.

Also you should hear it purge air when you lower the truck with a load on it. Either alt trailer height or using the settings in the radio.

Earl

 

[Cody Pereira]

Alright, here is an update. Went to my Interstate distributor and had the batteries load tested, both batteries failed to maintain voltage when the load was applied, so a few hundred bucks later - I have two new batteries. Seemingly, poor performing batteries were not linked to my issue.

Borrowed a buddies SnapOn Scantool and plugged it into the truck. Spit out a slew of codes related to the air suspension system as follows:

• C1556-96 Ride Height Air Pressure Sensor - Component Internal Failure - Stored
• C15A1-00 Unable to Obtain Desired Ride Height - Stored
• C1526-15 Left Rear Ride Height Sensor - Circuit Short to Battery or Open - Stored
• C211B-92 Ignition Run/Start Input - Performance or Incorrect Operation - Stored
• C1562-98 Ride Height Air Pump Control - Component or System Over Temperature - Stored

Cleared the codes and started the truck back up, and the following codes came back after cleared.

• C15A1-00 Unable to Obtain Desired Ride Height - Stored
• C1556-96 Ride Height Air Pressure Sensor - Component Internal Failure - Stored

Anyone have any idea what is going on here? I will do some digging on researching the codes on the interwebs.

 

[EZeis]

Alright, here is an update. Went to my Interstate distributor and had the batteries load tested, both batteries failed to maintain voltage when the load was applied, so a few hundred bucks later - I have two new batteries. Seemingly, poor performing batteries were not linked to my issue.

Borrowed a buddies SnapOn Scantool and plugged it into the truck. Spit out a slew of codes related to the air suspension system as follows:

• C1556-96 Ride Height Air Pressure Sensor - Component Internal Failure - Stored
• C15A1-00 Unable to Obtain Desired Ride Height - Stored
• C1526-15 Left Rear Ride Height Sensor - Circuit Short to Battery or Open - Stored
• C211B-92 Ignition Run/Start Input - Performance or Incorrect Operation - Stored
• C1562-98 Ride Height Air Pump Control - Component or System Over Temperature - Stored

Cleared the codes and started the truck back up, and the following codes came back after cleared.

• C15A1-00 Unable to Obtain Desired Ride Height - Stored
• C1556-96 Ride Height Air Pressure Sensor - Component Internal Failure - Stored

Anyone have any idea what is going on here? I will do some digging on researching the codes on the interwebs.

If you're wanting to fix it yourself, get a factory service manual. It will tell you how to troubleshoot by code.

These systems are fairly new and the codes can't be pulled by just any scan tool makes researching the codes difficult. Not to mention being pretty reliable systems.

Earl

 

[Hawk375]

Had the hose blow out of the reservoir tank and the air suspension would still operate, but it'd take longer as it no longer had stored pressurized air to assist it. Shoved the hose back into the tank and it's been fine since.

The tank is more to have quicker response and take some load off of the tiny air compressor.

 

[Jebruns]

I hear my 18 2500 bleed air every now and then. Seems like it's when I pull a trailer off the ball is when I notice it. Don't know if I've heard the compressor or not. Don't really pay it much mind. Our diesel pusher has air suspension with auto spitters, dump valves, etc. I've grown used to air systems just doing what they do. I'd be surprised if it were a sealed system though.

 

[Cody Pereira]

If you're wanting to fix it yourself, get a factory service manual. It will tell you how to troubleshoot by code.

These systems are fairly new and the codes can't be pulled by just any scan tool makes researching the codes difficult. Not to mention being pretty reliable systems.

Earl

I have always purchased a FSM with all previous vehicles, and have a Haynes book for this truck - but cannot find a printed version of the FSM anywhere. Do you happen to know where I can find one?