Another Air Ride issue -- But maybe control electronics?

[rogram]

Hi all.

So, I've spent several evenings reading through the forums and haven't found my exact case -- and the only similar ones got no resolution that I could find.
Foreshadowing, I no longer have any obvious leaks, but control and setup has only been partially successful. Among other things, I'm stuck with C156E error code

So, in early Sept (conveniently 4 days before fun knee reconstruction surgery) I was hitching up my trailer to my 16 Ram1500 and the rear decided to collapse. It seemed sudden, but in retrospect, it might have been trending a bit down over the previous month and though I heard the compressor try to help that day, it didn't do much. I figured it would lift up under way (had always done so previously) but it didn't, and then I saw for the first time the dreaded service suspension immediately, and drove right back home on the bump stops. I'll list what I've done and found so far. For context, I'm an engineer (I know, yuck), a reasonable mechanic (I have fun a motorcycle shop, mostly focusing on suspension for > 20 years, which means my cup runneth over with Nitrogen bottles and fittings, and springs, though most of them are steel coils.

1) I bought AlfaOBD and the MX+ interface
2) Got a new Dorman compressor/valveblock, which I had to return when it immediately leaked out the sensor interface
3) Got a new RMT rebuilt compressor/valveblock, which I had to return when it immediately leaked out between the pump body and end cap. Yay.
4) Also decided to do the rear air bags, since the truck just hit 93000 miles and it mostly get used towing at pretty much max capacity and it eliminated them (hopefully) as a variable

Where we are now is that the system hold nitrogen pressure (charged to 175 and filled bags via alfaOBD) and I have a total system mass about 185 bar-liters
Front seems even and at approx normal ride height
Rear seems even, but kind of stuck in OR2 height (just visually)

System Status shows normalish numbers
Component Air mass shows normalish numbers with total mass 187
I could inflate all 4 corners
I can pass a compressor circuit test
I can pass a spring circuit test
I can start a sensor test, and it seems to (by the clicks and compressor buzzing) to get 3 corners checked, but then times out before finishing the fourth and ends up reporting Failed
Similarly, when I try to do a Write Heights function, it starts cycling the compressor, which then runs a long time, and then times out.


So, I've been going around in circles for 4 days online and another 3 on the truck itself. It's sitting tall at the top and I can't write the heights, so I'm stuck with the #156 error, and dash warning messages. I really need my truck back for an event coming up and am running out of time. I'm willing to study and learn, but since some functions work and some don't, I'm not sure how to proceed. Most folks seem to figure out AlfaOBD and are golden. Mine fails. I haven't seen much talk of control module failures, but with timeouts, and kind of intermittently good data (it occasionally gives nonsense numbers), I wonder if I"m not barking up the wrong tree.

Have people seen or solved control electronics box failures, or could I have a 2nd bad unit from RMT?

Any and all advice appreciated.

Thanks
Roger

 

[Jeepwalker]

First off... good job for taking time to approach it like you have. I could throw out some scatter-gun ideas, but, I'm not really sure ....it sounds like you've dug into it well and covered a lot of the common bases. I guess, make sure all the sensor readings in AlfaOBD are reading 'right' and no intermittent failures there. I suspect you've done that a couple times.

If you haven't read the air-suspension chapter in the Ram *service* manual you should. With your background and knowledge, what you've learned so far, you would be a good candidate for reading it and learning the detailed nuances. It should help greatly. (just google it, you can find free manual via posts here). I hate to be the "Read the manual" guy, but seriously, it's very detailed. Read through the chapter quick the first time, don't worry if it's confusing. Then take a break & go back reading more closely. It gives you all the checks and step-by-step process.

The downfall of the manual is it is more methodical approach, not a quick *here's your answer sir* ..approach. But it is the gold standard and there might be something in there you haven't looked at enough. Once you get through this problem, you'll have a solid understanding and future snafu's you should know where to start looking.

Have you scanned youtube in case there are module issues with common bad solder joints, etc? That might be another thing I'd scan for. Modules are subjected to tens of thousands of heat/cool cycles, so something like that could crop up. But read the manual, do the checks they suggest. Hopefully you'll find it from there.

When it's working, it's a great system. But can be a head-scratcher when issues crop up.

 

[rogram]

Thanks. I don't mind someone being the "read the manual guy" because I'm usually that methodical guy who annoys others. I have literally hundreds of manuals here in my shop: Electronics (my "real" background), Motorcycles, Machining, and Hydraulics/Suspension. I guess I've let my guard down here in the internet era. The moreso because my suspension let go about 3 days before I went in for knee reconstruction and I couldn't even walk for weeks thereafter. It has really slowed down the crawling-under part the diagnosis. I need to google around and find that manual, and will literally be thrilled to read it. If I didn't have the time pressure of needing to be able to get my race-trailer/mobile-suspension workshop to Circuit of the Americas for the last big event of the year (racing and trackside support is very seasonal) I'd be a lot more chill about this. That having been said, I'm thrilled to read the manual. I didn't know it was readily available and will no go, somewhat embarrassed, look for it and read it. Thanks again or the pointer and nudge.

 

[rogram]

Hi JeepWalker. Could you point me to where this explanation is? I found the 2013-2016 pdf and found a bunch of suspension DTC references (truly numerous) but no real explanation or procedure, which I would be more than glad to read and learn. The pdf I have is not indexed so one has to search by word and it's pretty slow. I have cleaned the rear sensor connectors and they are more consistent in the data I read, but I need to go back and write the values. I was so surprised when it finally let me write values that I typed in the old stuff I had stored in haste rather than actual measurements (which are obvious on the front from the A-arm pivot but which I haven't figured out the right reference point on the rear. It now passes sensor test, compresssor test, and front spring tests, but times out on the rear spring test, even though they look good height and pressure wise. I'm starting to think they're not talking to the control module reliably and I'm wasting time poking about the air and mechanical stuff, but I have to try, both to learn and to rule out some stuff.

 

[Norman Roach]

Hi all.

So, I've spent several evenings reading through the forums and haven't found my exact case -- and the only similar ones got no resolution that I could find.
Foreshadowing, I no longer have any obvious leaks, but control and setup has only been partially successful. Among other things, I'm stuck with C156E error code

So, in early Sept (conveniently 4 days before fun knee reconstruction surgery) I was hitching up my trailer to my 16 Ram1500 and the rear decided to collapse. It seemed sudden, but in retrospect, it might have been trending a bit down over the previous month and though I heard the compressor try to help that day, it didn't do much. I figured it would lift up under way (had always done so previously) but it didn't, and then I saw for the first time the dreaded service suspension immediately, and drove right back home on the bump stops. I'll list what I've done and found so far. For context, I'm an engineer (I know, yuck), a reasonable mechanic (I have fun a motorcycle shop, mostly focusing on suspension for > 20 years, which means my cup runneth over with Nitrogen bottles and fittings, and springs, though most of them are steel coils.

1) I bought AlfaOBD and the MX+ interface
2) Got a new Dorman compressor/valveblock, which I had to return when it immediately leaked out the sensor interface
3) Got a new RMT rebuilt compressor/valveblock, which I had to return when it immediately leaked out between the pump body and end cap. Yay.
4) Also decided to do the rear air bags, since the truck just hit 93000 miles and it mostly get used towing at pretty much max capacity and it eliminated them (hopefully) as a variable

Where we are now is that the system hold nitrogen pressure (charged to 175 and filled bags via alfaOBD) and I have a total system mass about 185 bar-liters
Front seems even and at approx normal ride height
Rear seems even, but kind of stuck in OR2 height (just visually)

System Status shows normalish numbers
Component Air mass shows normalish numbers with total mass 187
I could inflate all 4 corners
I can pass a compressor circuit test
I can pass a spring circuit test
I can start a sensor test, and it seems to (by the clicks and compressor buzzing) to get 3 corners checked, but then times out before finishing the fourth and ends up reporting Failed
Similarly, when I try to do a Write Heights function, it starts cycling the compressor, which then runs a long time, and then times out.


So, I've been going around in circles for 4 days online and another 3 on the truck itself. It's sitting tall at the top and I can't write the heights, so I'm stuck with the #156 error, and dash warning messages. I really need my truck back for an event coming up and am running out of time. I'm willing to study and learn, but since some functions work and some don't, I'm not sure how to proceed. Most folks seem to figure out AlfaOBD and are golden. Mine fails. I haven't seen much talk of control module failures, but with timeouts, and kind of intermittently good data (it occasionally gives nonsense numbers), I wonder if I"m not barking up the wrong tree.

Have people seen or solved control electronics box failures, or could I have a 2nd bad unit from RMT?

Any and all advice appreciated.

Thanks
Roger

Your problem with the rear dropping when you hock up the trailer is air leaks at the valve body, rear air bag fitting at the airbag. Make sure the fittings are bottomed out and replace the O rings at the valve body and air bag. Read my post on air leaks. The air bags can not lift the extra load but it can lift your empty truck.

 

[rogram]

Thanks. Those are all new, but I'll double check them all. Previously (from 2016 until middle of this year) it lifted the full trailer well, even with front water tank filled (which adds close to 500lb on the front half of this trailer). I'm close to going delete, but want to try this longer to keep the nice ride when not loaded.

 

[Jacob Maguire]

Chased air-ride issues for quite some time. Amassed HVAC tools, fittings, gauges and much knowledge of the system. Kept diagrams of the entire system and what I've replaced.... From band-aids, after market and OEM replacement parts, every few months became exhausting. At the point of replacing failed individual o-rings across multiple fittings, finally decided the delete avenue the best approach. Now on coils and haven't thought about walking out to a collapsed truck in months!

Either way, good luck to you.
P.S. Post delete ride quality did NOT suffer. Use quality components and you will be sitting pretty. Additionally, after the initial conversion to coils, I've since gone upward by way of a Zone 6" lift. At that time, also did new UCA's(/ball joints), 1 new LCA due to a seized camber bolt, new tie rod ball joints, new sway bar end links, new hub assemblies, new passenger CV and intermediate shaft (+ bearings, seals and dust covers). Front end refreshed and the rear now supported by FOX2.0's and taller springs.

Fender liner removal race anyone!? I'll go first, blind-folded : )

 

[rogram]

Thanks for your input , even though i'm late getting back to it after being overseas traveling. I kept chasing things a while before, and right after my travels.And even after I got everything magically correct , the operation was intermittent , even though the sensors all showed okay , my external measurements. Communication between the main ecu and the suspension ecu end their control of the compressor was just too intermittent to throw anymore time at. I'm now eighty or ninety percent through a fifty percent air delete. I ended up with Fox 2.0s on the front, with preload set to ride abit over one inch taller than stock -- nothing that should throw off geometry , given that I think that's still puts it up a bit below off road one and well below whereoff road to used to be. On the rear I put in timber groves bags spring replacements with firestone bags and stainless hardware and brackets. I have only done a couple laps around the block so far, since I don't have the wheel liners, etc.back in yet, but the ride and height seem good. I just have them hard plumbed, separately, to a pair of schrader valves. My AirIQ HD2 should arrive today. The other thing I am trying to do which I haven't seen here, though I would be surprised if someone hadn't already done it, is to go with the optional air tank or faster, raising and lowering and using as an external compressor, but instead of buying their optional tank, i plan to plumb in the stock tanks, which are collectively larger than this , the aftermarket tank and already bought and paid for and already mounted basically just done. I aired them up with a schrader valve ended that last night and check the pressure today when I get to the same temperature and see how they hold. Does anyone see any reason not to use the stock tank in this application?Where it already exists from the OEM air suspension? I know the lines are slightly smaller comma but there are two of them so the differential isn't great compared to the merger, single line and should only maximum raising speed a tiny bit. As always, thanks for everyone's input