Air Suspension Issues

[EZeis]

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?

Believe you can only buy a disc verison for a computer. I think they stopped making printed ones years ago.

Tech Authority would have disc.

Earl

 

[Ltngdrvr]

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.

My comments from ramforumz

"Looks like a bad height sensor, your first set of codes indicates the left sensor.
Check the harness plug and check the harness to see if it may have a worn through area in the insulation somewhere along it.
I seem to remember someone who had harness wires crimped against the frame, check all along the harness up to the compressor.
If all checks out, then replace the sensor and hope that fixes it."

 

[Cody Pereira]

My comments from ramforumz

"Looks like a bad height sensor, your first set of codes indicates the left sensor.
Check the harness plug and check the harness to see if it may have a worn through area in the insulation somewhere along it.
I seem to remember someone who had harness wires crimped against the frame, check all along the harness up to the compressor.
If all checks out, then replace the sensor and hope that fixes it."

I pulled this connector out, cleaned it, and plugged it back in but will check the wiring backwards. Interesting that the code for the Ride Height Sensor did not come back on once cleared. It would make sense if these sensors are potentiometers to modulate the voltage giving the computer the ride height reading. I will pull this apart tomorrow again and check it. When I had the scantool connected, I went into the advanced settings to attempt to run a ride height sensor check, which failed seconds after initiating.

 

[dieselshadow]

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.

Can’t say anything about regens, this was about the air suspension system.

I’ve heard the air system work, but never a purge. Imagine this, I’ve started the truck almost every time it’s been started. Never heard it. Ever. Windows down, nope. Start and then exit the truck, nope. Listened for everything you guys says it does, never.

Don’t know what to tell ya. Just sharing with you my experience with my truck.

If it purges at every start up, then it must be perfectly damn near silent, like my wife. She purges every now and again, but claims it’s not possible.

 

[beaverguy]

Hey all, hoping I can find some help here on the forum regarding the recent issues I have been having with the rear air leveling suspension on my 2014 Ram 2500. I tow often on the weekends, so the system does get "worked" going between ALT Trailer mode and Normal mode in addition to the leveling feature when a load is in the bed.

Back in October, I started to have an intermittent issue with the air suspension on a particularly cold night (approx 29 degrees F - nothing crazy.) Started the truck and was met with a message saying "Immediate Air Suspension Service/Repair Required." I chocked it up to being a colder night and maybe the compressor was being cranky. I was not able to change the rear height. From then on, the message would only appear intermittently - no correlation to being cold, warm, rainy or dry. As time went on, the message would appear more frequently until the message appeared every time the truck was started.

I went through and checked all the electrical connectors; each ride height sensor for both sides, both connectors at the compressor itself. Unplugging them, cleaning with electrical contact cleaner and plugging back in. Checked the fuses (all three located under the hood related to the air suspension system) and they checked out good.

Truck is not losing air, the ride height does not change, indicating a presence of a leak in the system, so I am thinking it has to be a sensor or connection? Upon starting, the system will purge the air, but then the compressor will not kick on to adjust.

I am not someone to take the truck to the dealer unless I have to - heard some horror stories during my searches of people having issues with the air suspension and having the dealers just throw parts at it hoping something will work with the most common being throwing a new compressor in which in all cases I have read, does not fix it. I find it hard to think that the compressor is my issue, as if the compressor was locked up, it would be blowing the fuse repeatedly.

Can someone lend a hand here? I am at a loss, and there is not much information regarding these systems for the HD trucks (much more on the 1500's.)

Thanks in advance!!

CHECK THE GROUND ON COMPRESSOR AND OTHER RELATED ITEMS I had similar problems and it was the ground..

 

[kcv67]

Are the ride height sensors the same left and right? If they are switch them and see if the code follows.

 

[Cody Pereira]

Are the ride height sensors the same left and right? If they are switch them and see if the code follows.

I checked the PN's and they are different which makes sense on how they are mounted to the frame. Since I cleared the codes after seeing the sensor code the first time, it has not come back. Pulled the compressor down off the frame today, took apart all the connectors, cleaned them and put back together. Removed, cleaned and reinstalled the ground to the frame between the compressor and reservoir as well. Checked the harness from the compressor as far forward as I could for damage or shorting. Since the compressor has not kicked on in quite a while to maintain the reservoir pressure, the truck is sitting on the rubber stops. Probably was not a good idea for me to have been selecting the Alt height mode while troubleshooting, as the repeated dumping of air depleted the system.

Even now, the truck when started will purge, and you can hear the valve block engaging which would be followed by the compressor activating (which does not happen.)

Starting to get very frustrated, will surely not recommend this system to anyone. Wonderful when it works, but when there is an issue or failure, you are left with an inoperable rear suspension.

 

[Ltngdrvr]

What codes are showing now???
Hate to say it, but you may have to let a dealer tech work on it.

 

[Cody Pereira]

What codes are showing now???
Hate to say it, but you may have to let a dealer tech work on it.

It does seem that I am getting closer to that option, which really sucks. The only codes that are now showing are:

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

A friend of mine allowed me access to his AllData, where I was able to retrieve the diagnostic steps for the C1556-96 code which I am going to try tomorrow. I ran an air mass, pressure, and sensor check on the compressor and bags, which yielded "Air Mass OK." which was good to see. I have pressurized readings in both bags (equal - further confirming no leak) and in the reservoir tank. Albeit, these readings were a bit lower than where they should be due to the dumps to alt height with no compressor to recover.

 

[Ltngdrvr]

It does seem that I am getting closer to that option, which really sucks. The only codes that are now showing are:

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

A friend of mine allowed me access to his AllData, where I was able to retrieve the diagnostic steps for the C1556-96 code which I am going to try tomorrow. I ran an air mass, pressure, and sensor check on the compressor and bags, which yielded "Air Mass OK." which was good to see. I have pressurized readings in both bags (equal - further confirming no leak) and in the reservoir tank. Albeit, these readings were a bit lower than where they should be due to the dumps to alt height with no compressor to recover.

Well, that still looks like a ride height sensor is bad.

 

[sag2]

Actually the fault does not have anything to do with the ride height sensors. The fault indicates the pressure sensors in the pump assembly have failed, B+ and ground problem to the pump, or the wiring between the pump and ASCM is suspect.

 

[EZeis]

FYI, I seen a recent TSB that states individual parts are now available for the air compressor module.

Earl

 

[Cody Pereira]

Actually the fault does not have anything to do with the ride height sensors. The fault indicates the pressure sensors in the pump assembly have failed, B+ and ground problem to the pump, or the wiring between the pump and ASCM is suspect.

In the process now of troubleshooting each of those items. Really hoping the issue is not internal to the pump itself and rather a wiring condition as long as it is easy to find (yeah right.)

FYI, I seen a recent TSB that states individual parts are now available for the air compressor module.

Earl

Do you happen to know which TSB that is? Worst case scenario, if the pump components are shot - at least there is some hope that I can replace certain components as opposed to the assembly.

 

[Cody Pereira]

PROBLEM SOLVED.

I decided to take another look at the compressor assembly while going through the diagnostic testing. As mentioned before, the system seemed to be fully functioning up until the air pressure sensor called for the compressor to engage. Unbolted the assembly once again, supported it, and double checked all the electrical connections within the assembly. The good ol' "grab each wire to make sure nothing is loose" trick actually worked. While tracing back the two power wires (Connector C2 - Assembly Air Suspension Compressor Feed; Orange/Brown wire (Y40)) I found that the brown wire was physically disconnected from the air compressor body. (photo attached) The positive wire was not long for the world, ready to break off.

The connection to the air compressor itself is pretty bad... this truck is a 2014, meticulously washed but get this connection corroded itself off the body. Note that there is NO post style connection, it appears that the connections are potted at the factory, which is a process of embedding the connection into the black resin seen in the photo. As a test, I started the truck and held the wire to the connection which immediately started the compressor once the sensor deemed necessarily. Truck lifted off from the bump stops as the bags filled. Rechecked the system with the scan-tool, and retrieved data from the ASCM, with a reservoir pressure now at 125psi (up from 38 psi prior.)

Now the fix. As I do not want to "bench repair" the connection, requiring the system to be disconnected and bleed all air from the tanks and bags (which according to ALLDATA, required recharging with Nitrogen by the dealer.) I am planning on re-soldering new wire pigtails back onto the compressor body to sit within the existing potted cups shown in the attached photo.

I am hoping that this entire process can help others in a similar situation. We know that a valiant attempt at fixing issues with these trucks (or any vehicle for that matter) without heading to the dealer is the best move if mechanically inclined. I offer anyone to PM me with any similar situations and I can help as much as I can - sure learned a ton about these systems from this.

P.S. - The air system on the 2500's are certainly an open system to the atmosphere - proven by the ability for my previously depleted system to regain pressure through the on board air compressor without recharging through the reservoir. Cool system, but honestly a PITA when there are issues.

Cheers all.

 

[sag2]

FYI, I seen a recent TSB that states individual parts are now available for the air compressor module.

Earl

If there is I can't find it, at least for 2014.

 

[Ltngdrvr]

PROBLEM SOLVED.

I decided to take another look at the compressor assembly while going through the diagnostic testing. As mentioned before, the system seemed to be fully functioning up until the air pressure sensor called for the compressor to engage. Unbolted the assembly once again, supported it, and double checked all the electrical connections within the assembly. The good ol' "grab each wire to make sure nothing is loose" trick actually worked. While tracing back the two power wires (Connector C2 - Assembly Air Suspension Compressor Feed; Orange/Brown wire (Y40)) I found that the brown wire was physically disconnected from the air compressor body. (photo attached) The positive wire was not long for the world, ready to break off.
View attachment 126172
The connection to the air compressor itself is pretty bad... this truck is a 2014, meticulously washed but get this connection corroded itself off the body. Note that there is NO post style connection, it appears that the connections are potted at the factory, which is a process of embedding the connection into the black resin seen in the photo. As a test, I started the truck and held the wire to the connection which immediately started the compressor once the sensor deemed necessarily. Truck lifted off from the bump stops as the bags filled. Rechecked the system with the scan-tool, and retrieved data from the ASCM, with a reservoir pressure now at 125psi (up from 38 psi prior.)

Now the fix. As I do not want to "bench repair" the connection, requiring the system to be disconnected and bleed all air from the tanks and bags (which according to ALLDATA, required recharging with Nitrogen by the dealer.) I am planning on re-soldering new wire pigtails back onto the compressor body to sit within the existing potted cups shown in the attached photo.
View attachment 126173
I am hoping that this entire process can help others in a similar situation. We know that a valiant attempt at fixing issues with these trucks (or any vehicle for that matter) without heading to the dealer is the best move if mechanically inclined. I offer anyone to PM me with any similar situations and I can help as much as I can - sure learned a ton about these systems from this.

P.S. - The air system on the 2500's are certainly an open system to the atmosphere - proven by the ability for my previously depleted system to regain pressure through the on board air compressor without recharging through the reservoir. Cool system, but honestly a PITA when there are issues.

Cheers all.

Well, I at least sort of called it as a bad connection.
The only thing I can see about the plan for fixing it, is that the corrosion looks to be well down inside the wire.
Is that round plug surrounding the wires not something that will come out so you can get down past the corrosion?

 

[sag2]

Glad you found it. So the diagnostic procedure was right on. First three probable causes for the fault.

Intake/exhaust air suspension lines blocked or restricted
Air suspension air compressor feed circuit open or high resistance
Ground circuit open or high resistance

Good luck getting those wires repaired. The neighbor had a similar situation with a winch motor and it was very difficult to get the potting material off the wires. He ended up using a Dremel with a small bit to carefully clean away the material. It was a slow process.

 

[p-Bar]

Why don't you solder wires to brass wood screws and screw them down into the middle of the wires. Mc Gyver

 

[sag2]

Why don't you solder wires to brass wood screws and screw them down into the middle of the wires. Mc Gyver

That could be a great fix. Never thought of that one.

 

[EZeis]

Copy of the Ram internal memo on compressor module individual parts.

9004022 12/11/2019 MY11-19 All Makes/Models
GPOP - Issue Review System
Part Number: 68204730A$, 68041137A$, 04877128A$
Part Description: Air Suspension Components
Issue
Description:
Star Parts Catalog has been updated to show individual service parts for the
compressor assembly. This will allow service technicians to repair the root cause
without over repairing the system. Replace only the part deemed failed by the
diagnostics performed.
Individual parts include:
- Compressor
- Valve block
- Individual hoses
- Temp sensor
- Shield
- Air line clips
NOTE: in most situations when a new compressor is needed, the compressor as a
separate part is the correct repair, and the assembly would not be required.