Diagnosing Air Suspension Leaks - Suggestions?

[wes8398]

TL;DR - Suspension is losing air somewhere. Pulled compressor fuse for a few days to confirm, and front driver's corner dropped 2+ inches. Does this confirm a leak at that corner, or would the valve block still be allowing air to move even with the compressor disabled?

First off - I'm pretty familiar with the system and wrenching in general, so please consider this.

So...

- Truck is set up to sit 37" ground-to-fender on all 4 corners (in "normal" mode) via adjustable links & Alpha programming.
- The last few weeks I've been noticing the heights look off after the truck sits overnight or for a few days.
- Instant "oh ****, here we go" thoughts start flooding my brain.
- Checked all the obvious stuff - sensor links are all in tact, battery isn't dead or compromised, etc.
- Ran AlphaOBD checks and nothing looks glaringly fooked (height sensor checks / tests go fine).
- Its worth mentioning that the compressor, valve block, various fittings, and the front air struts were all replaced with brand new parts by a Ram dealer before I bought the truck a year and a bit ago.

So I've pulled the compressor fuse to see if/how fast I'm losing air. After 4 days of a little driving but mostly sitting, my front driver corner is down to 34" (and other corners are off by a smaller amount due to that corner dropping, I figure).

Is it safe to assume that with a disabled compressor, I've isolated the leak to the driver's front corner? Or would the valve block still be opening/closing/allowing air movement even with the compressor being disabled?

Any other thoughts or advice (besides to just swap to conventional suspension)?

 

[Jeepwalker]

Have you read the air suspension section of the service manual? Being technical minded, DIY guy, you might find it helpful. It's very comprehensive and probably the best air suspension resource out there. There are a lot of how-to testing & de-bugging processes outlined in it. Once you read it, you will have a greater understanding how it all works down to the last detail. Will help in the future too. One thing I will say is air bags tend to wear out faster in cold (and rusty) climates).

Should be able to download a copy Here.

 

[wes8398]

Have you read the air suspension section of the service manual? Being technical minded, DIY guy, you might find it helpful. It's very comprehensive and probably the best air suspension resource out there. There are a lot of how-to testing & de-bugging processes outlined in it. Once you read it, you will have a greater understanding how it all works down to the last detail. Will help in the future too. One thing I will say is air bags tend to wear out faster in cold (and rusty) climates).

Should be able to download a copy Here.

Thanks for the reply. I haven't bothered with the service manual, as its reputation is less than stellar amongst these interwebs. And if that's what the dealerships are using to diagnose/repair these systems, then I want nothing to do with it, because most of those places haven't got a clue how to work on these things. Alas, thank you very much for the link and I will go and find out for myself how helpful it is. I love getting into the nitty gritty and fine details of stuff like this.... just for the pure enjoyment of learning it.

 

[Roman217]

See my post in one of the other air suspension threads: https://www.ramforum.com/threads/ride-height-with-alfaobd-air-suspension.148828/post-2839539

The valve block still cycles even with the air compressor fuse being pulled. The valve block reads the pressures so it cycles through all the air bags and main tank. The left side will sink little by little due having more weight between the fuel tank and the driver.

 

[wes8398]

Oh, I'm sure I've come across it, as I've perused about every single thread available on the topic over the last year or so of owning this truck. I like to be prepared. I've since put new Arnott rear bags in, soap tested all my fittings and connections, and refilled with nitrogen (thanks for the tools HVAC neighbour guy!!), and am back up and running without issue. The only thing left lingering in my mind is perhaps plugging the ambient air intake hose to prevent the introduction of outside air and make it more obvious the next time there's a leak. But I don't want to cause the compressor to burn itself out trying to pull air from a blocked intake, so I'm trying to confirm whether it'll effectively self-preserve, or self destruct.

 

[Roman217]

You're more likely to ruin something plugging it than preserving anything. It should never pull from the atmosphere and it does have a drying process to limit moisture. If you ever hear a low pitch whistle it's going through the refill procedure and that should be the point to check for leaks.

 

[Jeepwalker]

The manual is really is the definitive source on the air ride. I doubt many techs have thoroughly read through it. If you want to debug your system give it a look.

 

[wes8398]

The manual is really is the definitive source on the air ride. I doubt many techs have thoroughly read through it. If you want to debug your system give it a look.

Did something change as of late, or are we referring to the same manual that misleads all these "techs" into changing unnecessary parts and consistently misdiagnosing problems? The same manual that calls it a "sealed system" several times, too? And the same manual that takes absolutely zero account for the potential of moisture/condensation of ambient air wreaking havoc on this system in subzero temperatures? Yah, no thanks.

 

[Jeepwalker]

....are we referring to the same manual that misleads all these "techs" into changing unnecessary parts and consistently misdiagnosing problems? The same manual that calls it a "sealed system" several times, too?

Yes ...that's the first thing on the manual, "Replace the most expensive parts 3x." Thats right above "Elvis is living in Memphis", "JFK is alive" and "The moon landing was faked".

 

[Jeepwalker]

You might be better off converting yours over to regular shocks, if you don't want to dig into it, or pay the dealer.

The air ride system is simple in concept & design, basically very similar to air-ride systems of the 90's ..with some changes, tweaks and computer integration. Guys here on this forum or on youtube can point to the common issues, but the truth is there is a near infinite number of places along the entire system (beyond the key failure points (air-struts/compressor/valves/sensors)) where a failure could occur. You're only going to get scattergun suggestions w/o digging into it in a logical maner. And that's going to waste time.

The best and quickest way is to take a methodical approach which the manual outlines (I've read the entire section). Complete with air and voltage checks. To a technician an air ride system is a massive headache because it takes a lot of time and the possibility of come-backs is extremely high (unpaid work) ...when he/she could be doing simpler and better paying jobs with less come-back potential. I suspect most techs haven't read the entire manual ...or haven't read it enough times. A guy who was a true expert on the Ram air ride could make a lot of money and please customers day in and day out. I used to do a lot of air ride suspension repairs ..I thought they were fun.

 

[wes8398]

You might be better off converting yours over to regular shocks, if you don't want to dig into it, or pay the dealer.

The air ride system is simple in concept & design, basically very similar to air-ride systems of the 90's ..with some changes, tweaks and computer integration. Guys here on this forum or on youtube can point to the common issues, but the truth is there is a near infinite number of places along the entire system (beyond the key failure points (air-struts/compressor/valves/sensors)) where a failure could occur. You're only going to get scattergun suggestions w/o digging into it in a logical maner. And that's going to waste time.

The best and quickest way is to take a methodical approach which the manual outlines (I've read the entire section). Complete with air and voltage checks. To a technician an air ride system is a massive headache because it takes a lot of time and the possibility of come-backs is extremely high (unpaid work) ...when he/she could be doing simpler and better paying jobs with less come-back potential. I suspect most techs haven't read the entire manual ...or haven't read it enough times. A guy who was a true expert on the Ram air ride could make a lot of money and please customers day in and day out. I used to do a lot of air ride suspension repairs ..I thought they were fun.

I don't know why you're talking to me like a noob here, bud, but it's uncalled for. I know this system better than the techs do at 3 dealers around me. One of them has a master tech who's an old highschool friend of mine who has actually thanked me for opening their eyes to how to properly diagnose and repair these things. No joke. I've been wrenching on my own vehicles for 20+ years and take pride in the fact that I learn what I'm doing inside out and backward and forward before doing so - and this job was no different. Since most of my questions have almost always been asked previously and answered ad nauseum, I do so by reading a lot more than posting... and that includes accessing resources like alldata and so on for shop manuals, etc. All that to say you and your "maybe you'd be better off converting to coils" presumptions can go ahead and kick rocks. My truck is in order, no thanks to attitudes like yours, but many, many thanks to those who have contributed useful information to various forums and other platforms over the years

 

[Jeepwalker]

No ill will intended. I *tried* giving the most useful info I could think of ....there's many possibilities, the troubleshooting guide in the manual is the best reference, I can think of. I even provided a link where you could download it for Free. Your response was, (presumably w/o having read through the air ride section), 'The manual is no good', (paraphrasing here) ...'teaches techs to give bad advise/change wrong parts'. That was an aggressive response IMO. Ummmm... I mean ..what do ya say to responses like that when a guy hasn't even cracked the manual open??

The truth is, and sorry to repeat myself here, ...it's an entire "system". There are many possible failure points. People advising "it's THIS", Or "Do That" is going to be a complete waste of your time checking hither and fro, given that the dealer has already done the 'easy' things. There's air tubing all over the truck, sensors, check valves, valves, compressor, module. Could be any one of those or multiples of them at the same time. Corroded connector pin ...mouse chewed a hole in wires/tubing??/Bad or Stuck valves/flaky module ...Who knows? It's all fully serviceable. But it's going to take a methodical eyes-on, hands-on approach. No shortcuts. That's why the dealer techs haven't resolved the problem, there's a lot to check and look into. Maybe they fixed one problem, but there are multiple? The detailed step-by-step info is out there ... just a few clicks away.

The air ride system is a great system when working properly. It sounds like you HAVE the ability to do it. Hope you get yours going

.

 

[wes8398]

No ill will intended. I *tried* giving the most useful info I could think of ....there's many possibilities, the troubleshooting guide in the manual is the best reference, I can think of. I even provided a link where you could download it for Free. Your response was, (presumably w/o having read through the air ride section), 'The manual is no good', (paraphrasing here) ...'teaches techs to give bad advise/change wrong parts'. That was an aggressive response IMO. Ummmm... I mean ..what do ya say to responses like that when a guy hasn't even cracked the manual open??

The truth is, and sorry to repeat myself here, ...it's an entire "system". There are many possible failure points. People advising "it's THIS", Or "Do That" is going to be a complete waste of your time checking hither and fro, given that the dealer has already done the 'easy' things. There's air tubing all over the truck, sensors, check valves, valves, compressor, module. Could be any one of those or multiples of them at the same time. Corroded connector pin ...mouse chewed a hole in wires/tubing??/Bad or Stuck valves/flaky module ...Who knows? It's all fully serviceable. But it's going to take a methodical eyes-on, hands-on approach. No shortcuts. That's why the dealer techs haven't resolved the problem, there's a lot to check and look into. Maybe they fixed one problem, but there are multiple? The detailed step-by-step info is out there ... just a few clicks away.

The air ride system is a great system when working properly. It sounds like you HAVE the ability to do it. Hope you get yours going

.

No ill will here either. I just don't take kindly to *perceived* condescension. Only having typing to read leaves a lot to be assumed, and sometimes incorrect perceptions, so I'll take the blame on that. To be honest, I hadn't even realized that you were the one who'd replied earlier in the thread. As I recall, the link was either broken or otherwise didn't work when I attempted it.
Anyway... As I said, it's back up and running. I'm thankful to have caught it before winter, because the repair would have been a whole different can of worms in those conditions.
Thanks for your time.

 

[Jeepwalker]

Glad you got it working!

The manual link is still good. I just checked it. Not the first link .....scroll down to near the bottom of the page (of said link). There you will see a list of manuals which will take you to a google docs page where you can click "download" for the 2016 manual. It's not my docs. But it works ..says it's too large, but it works. Read through the subsequent posts in that link if you have problems. If you're going to own your Ram for a while, I would definitely download your truck's manual, as a future reference. You might need it for something else. And, who knows, it may not be available at some point in the future.

Cheers brother!

 

[JTBroadfoot]

I have the factory manual for the Ram 1500 DS pickup. After having issues with the Air Suspension System, the following is what I have learned via the manual, visual inspection and experimentation. The Factory manual diagnostic info and wiring diagrams have been very helpful.

The system consists of Air Spring assemblies at each wheel, an Air Reservoir, an Air Compressor, an Air Distribution Valve Block, Ride Height Sensors at each wheel and a lot of associated plumbing. The system is initially charged with nitrogen to help control internal moisture and corrosion. The system is governed by the Air Suspension Computer Module (ASCM). The ASCM also communicates with other on-board computer modules to help it do its job. Air Suspension options can be set via the EVIC and Steering wheel buttons or the Uconnect Radio screen depending on the vehicle trim level. Manual height adjustment is handled by a pair of buttons on the dash.

The compressor has three ports, a Reservoir port connected directly to the Reservoir tank pair, a Valve Block port connected directly to Port P on the valve block and a port connected to a hose that terminates just above the RR taillight assembly in an air filter/water separator that is open to the atmosphere. If the compressor overheats, a temperature sensor signals the ASCM. The compressor has a pair of reversing valves that allow the compressor to do the following tasks.

• Move air from the reservoir to one or more of the corner springs. This requires the compressor reversing valves to the connect compressor Input to the reservoir line, connect the compressor Output to the air suspension solenoid Valve block (Port P) and then open the Air Tank Enable Solenoid valve and the correct spring valve(s) and start the compressor.
• Move air from one or more springs to the reservoir. This requires the compressor reversing valves to connect compressor Output to the reservoir line, connect compressor Input to the air suspension solenoid Valve block (Port P) and then open the Air Tank Enable Solenoid valve and the correct spring valve(s) and start the compressor.
• Add outside air to the reservoir to Increase Air Mass. This requires reversing valves to connect the outside filtered air hose to the compressor Input and connect the air tank reservoir to the compressor Output. When finishing an increase, the unit back vents an amount of excess air back through the filter to clear any moisture in the filter.

The Air Distribution Valve Block has 6 ports. Five of these have solenoid valves. 4 of the ports are marked and each connects to its respective wheel. A 5th marked “P” goes to the compressor. The 6th is marked “out”, appears to have no solenoid control and is connected to an open hose that terminates above the RR tail light. I believe this port is used by an internal pressure relief valve that vents excess air mass if the pressure rises above limits for any reason. The Valve Block also has a Pressure Sensor that is monitored by the ASCM.

Normal suspension adjustments are handled by compressor tasks 1 and 2 above based on input from the ASCM. For normal operation, the system is closed. The ASCM monitors total air mass and if it goes below its limit, task 3 is used to add outside air to the system. This is not a normal situation but the manual indicates the system can tolerate very minor leaks. Normally the compressor is moving air between two pressure vessels (tank and spring), so the pressure differential is not very high. When replacing lost Air Mass, it must raise air pressure from atmospheric to the full system pressure. This requires harder work for a longer time. This can lead to compressor issues as well as deplete the nitrogen charge over time. If this happens very often, it’s time to find out why and get it repaired. If you are around the vehicle and hear the compressor run and then a short exhaust of air, you are hearing it make up some air mass.

The DTC codes for the Air Suspension system include a number that are labeled Overuse DTC’s. Some scan tools (like the one I used) will read air suspension DTC codes. Only the best will also provide dynamic data display and take freeze frames to tell you what the Sensors are seeing, and what the components are doing under driving conditions. I now understand why others are appreciative of AlphaOBD.

My issue has been the RR dropping occasionally when left to its own devices while not being driven. This has gotten worse over time and I was slow to act. I had discovered that by turning the Air Suspension off when I was not using the truck (press both dash buttons together for at least 5 seconds), the truck would stay up. Had to leave it for 2 weeks and it was still up when I returned. On rare occasions, turning it off didn’t seem to work as time went on. On rare occasions it started dropping at highway speeds. It would recover after a few miles.

Testing the different height levels over several days allowed me to come to at least one conclusion. The RR air spring does have an intermittent leak. Thanks to the forum for helping me to even think about an intermittent leak. Neither level Off Road 1 or 2 would leak down. Normal Ride Height would go down occasionally. I don’t have the tools to manually engage Aero mode, but it is happening on the highway more often. In the Entry/Exit Mode it always comes down immediately. The amount of time I have allowed to elapse since this started, may have stressed the compressor and valve body, as I have seen overuse codes. I have an appointment a few towns away with a dealer I trust to get the system fixed and recharged.

To anyone who has managed to read this far, I would appreciate any feedback about what I have misunderstood or missed. Thanks to the forum providers and all who post here.

 

[wes8398]

I have the factory manual for the Ram 1500 DS pickup. After having issues with the Air Suspension System, the following is what I have learned via the manual, visual inspection and experimentation. The Factory manual diagnostic info and wiring diagrams have been very helpful.

The system consists of Air Spring assemblies at each wheel, an Air Reservoir, an Air Compressor, an Air Distribution Valve Block, Ride Height Sensors at each wheel and a lot of associated plumbing. The system is initially charged with nitrogen to help control internal moisture and corrosion. The system is governed by the Air Suspension Computer Module (ASCM). The ASCM also communicates with other on-board computer modules to help it do its job. Air Suspension options can be set via the EVIC and Steering wheel buttons or the Uconnect Radio screen depending on the vehicle trim level. Manual height adjustment is handled by a pair of buttons on the dash.

The compressor has three ports, a Reservoir port connected directly to the Reservoir tank pair, a Valve Block port connected directly to Port P on the valve block and a port connected to a hose that terminates just above the RR taillight assembly in an air filter/water separator that is open to the atmosphere. If the compressor overheats, a temperature sensor signals the ASCM. The compressor has a pair of reversing valves that allow the compressor to do the following tasks.

• Move air from the reservoir to one or more of the corner springs. This requires the compressor reversing valves to the connect compressor Input to the reservoir line, connect the compressor Output to the air suspension solenoid Valve block (Port P) and then open the Air Tank Enable Solenoid valve and the correct spring valve(s) and start the compressor.
• Move air from one or more springs to the reservoir. This requires the compressor reversing valves to connect compressor Output to the reservoir line, connect compressor Input to the air suspension solenoid Valve block (Port P) and then open the Air Tank Enable Solenoid valve and the correct spring valve(s) and start the compressor.
• Add outside air to the reservoir to Increase Air Mass. This requires reversing valves to connect the outside filtered air hose to the compressor Input and connect the air tank reservoir to the compressor Output. When finishing an increase, the unit back vents an amount of excess air back through the filter to clear any moisture in the filter.

The Air Distribution Valve Block has 6 ports. Five of these have solenoid valves. 4 of the ports are marked and each connects to its respective wheel. A 5th marked “P” goes to the compressor. The 6th is marked “out”, appears to have no solenoid control and is connected to an open hose that terminates above the RR tail light. I believe this port is used by an internal pressure relief valve that vents excess air mass if the pressure rises above limits for any reason. The Valve Block also has a Pressure Sensor that is monitored by the ASCM.

Normal suspension adjustments handled by compressor tasks 1 and 2 above based on input from the ASCM. For normal operation, the system is closed. The ASCM monitors total air mass and if it goes below its limit, task 3 is used to add outside air to the system. This is not a normal situation but the manual indicates the system can tolerate very minor leaks. Normally the compressor is moving air between two pressure vessels (tank and spring), so the pressure differential is not very high. When replacing lost Air Mass, it must raise air from atmospheric to the full system pressure. This requires harder work for a longer time. This can lead to compressor issues as well as deplete the nitrogen charge over time. If this happens very often, it’s time to find out why and get it repaired. If you are around the vehicle and hear the compressor run and then a short exhaust of air, you are hearing it make up some air mass.

The DTC codes for the Air Suspension system include a number that are labeled Overuse DTC’s. Some scan tools (like the one I used) will read air suspension DTC codes. Only the best will also provide dynamic data display and take freeze frames to tell you what Sensors are seeing, and what components are doing under driving conditions. I now understand why others are appreciative of AlphaOBD.

My issue has been the RR dropping occasionally when left to its own devices while not being driven. This has gotten worse over time and I was slow to act. I had discovered that by turning the Air Suspension off when I was not using the truck (press both dash buttons together for at least 5 seconds), the truck would stay up. Had to leave it for 2 weeks and it was still up when I returned. On rare occasions, turning it off didn’t seem to work as time went on. On rare occasions it started dropping at highway speeds. It would recover after a few miles.

Testing the different height levels over several days allowed me to come to at least one conclusion. The RR air bag does have an intermittent leak. Thanks to the forum for helping me to even think about an intermittent leak. Neither level Off Road 1 or 2 would leak down. Normal Ride Height would go down occasionally. I don’t have the tools to manually engage Aero mode, but it is happening on the highway more often. In the Entry/Exit Mode it always comes down immediately. The amount of time I have allowed to elapse since this started, have stressed the compressor and valve body, as I have seen overuse codes. I have an appointment a few towns away with a dealer I trust to get the system fixed and recharged.

To anyone who has managed to read this far, I would appreciate any feedback about what I have misunderstood or missed. Thanks to the forum providers and all who post here.

Congratulations! You've educated yourself to the point of likely having a better grasp of this system than most of the dealership techs who are going to be working on your truck. Sad, but true. Prepare yourself for a long, drawn out back-and-forth with them unless you're lucky enough to get a tech who actually knows how to diagnose/fix these things. To be fair, some of them actually DO know better, but the troubleshooting procedures FCA provides are awful and more sales oriented than technically accurate. They'll blame everything from the compressor to valve block to fittings/lines (and sell these items to you only to NOT fix the problem) before they finally address the issue, which is almost always leaking air bladders. Sure, there might be other issues if you've been running with a large leak for a long time, but the first domino to fall is almost always a leaky bag (or more). If you insist on taking it to a dealer, then I would be *adamant* that the *first* thing they do is a soapy water test on all 4 air bladders *at each individual ride height*. That means pulling back the plastic dust shield on the rears, and using mirrors or other tricks to get a visual on the fronts underneath the aluminum covers that protect them. And make *sure* they completely purge and refill the system *with n2* after they've replaced any components.

 

[MSandRebel]

From what you’re describing I would say your RR air bag is leaking but only at a certain ride height. This happens cause the bag rolls or collapses on itself depending on the ride height. When it rolls on it’s self, it’ll seal off where the bag is getting porous.

 

[JTBroadfoot]

Wes8398 thanks for your reply. Diagnostics were run as you suggested. The new dealer is in the third or fourth generation of family ownership and seems to actually think about this stuff.

MSandRebel, thanks for the reply. That's what I think as well. The dealer's diagnosis is no leaks but a bad controller. They see communication errors. If there are no leaks, how does the system loose air mass which I can hear it replace at intervals. Does anyone know if the O or exhaust port on the Air Distribution valve body is controlled by a high-pressure relief valve or is operated in conjunction with the pressure tank port solenoid. Having trouble figuring out how a bad controller can let the Air out. Betting I have to get a new RR air spring. Truck is currently waiting for parts for both the air suspension and an exhaust system sensor that the old dealer was unable to get out of the SCR. Have much more faith in new dealer.

 

[Hooke Road]

Oh, I'm sure I've come across it, as I've perused about every single thread available on the topic over the last year or so of owning this truck. I like to be prepared. I've since put new Arnott rear bags in, soap tested all my fittings and connections, and refilled with nitrogen (thanks for the tools HVAC neighbour guy!!), and am back up and running without issue. The only thing left lingering in my mind is perhaps plugging the ambient air intake hose to prevent the introduction of outside air and make it more obvious the next time there's a leak. But I don't want to cause the compressor to burn itself out trying to pull air from a blocked intake, so I'm trying to confirm whether it'll effectively self-preserve, or self destruct.

If your vehicle doesn't have built-in safety mechanisms, you might consider periodically unblocking the intake to allow the compressor to draw in fresh air. This way, you can periodically test for leaks without causing excessive strain on the compressor.

 

[wes8398]

Wes8398 thanks for your reply. Diagnostics were run as you suggested. The new dealer is in the third or fourth generation of family ownership and seems to actually think about this stuff.

MSandRebel, thanks for the reply. That's what I think as well. The dealer's diagnosis is no leaks but a bad controller. They see communication errors. If there are no leaks, how does the system loose air mass which I can hear it replace at intervals. Does anyone know if the O or exhaust port on the Air Distribution valve body is controlled by a high-pressure relief valve or is operated in conjunction with the pressure tank port solenoid. Having trouble figuring out how a bad controller can let the Air out. Betting I have to get a new RR air spring. Truck is currently waiting for parts for both the air suspension and an exhaust system sensor that the old dealer was unable to get out of the SCR. Have much more faith in new dealer.

This is pretty classic dealership BS regarding air ride... throw small, more affordable parts at it until they've dug you in deep enough to say ok, it's still not fixed and we're going to have to replace *insert the BIG ticket items here*.

Will they tell you how they "tested" for leaks? And did you ask them the obvious question of where the N2 went if there aren't any leaks? They're trying to say the valve block is randomly bleeding it off when it shouldn't? Unlikely... UNLESS, that *is* the case, *but* this is just a symptom of the larger issue (a leak --> moist air in the system --> freezing moisture --> havoc).

The ONLY way they can properly pinpoint leaking bags/connections/lines is by spraying soapy water on these parts and observing as the system operates. For the bags, this means removing the dust covers on the rear bags to visualize (a time consuming PITA that a dealer won't wanna do), and putting some effort into getting a good visual on what they can see of the front bags under the aluminum protective covers that hide most of them (another PITA that dealerships don't wanna do).