[northcreek]

Jayman

I take back what I earlier said regarding the leveling sensors.There is a condition where if the left sensor goes bad the compressor disregards that signal and relies on the right sensor for input,if that sensor goes bad too the system is disabled except for the inflator.
There are three possible DTC,s that are displayed by the LED at the inflator control.These are blinking pulses of one,two or three and are repeated until the problem is corrected.....are you seeing any DTC,s?...Mike.
001 system disabled
002 left sensor
003 right sensor

 

[Jayman]

Okay great I will certainly check. Question though; should I notice this DTC activity with key off, key on, or key on engine running?
Thanks Mike!
Jay

 

[northcreek]

Jayman

I believe key on.The way I understand it is that once the key is switched off the codes will clear if the problem has been corrected,so if your problem is intermittent the codes might not be present and you would have to wait until it acts up again also it could be a problem outside of the three DTC,s....hope this helps..Mike.

 

[Jayman]

Thanks again. No DTC's (flashing lights) on the inflator.
I also read that the connector can be a problem on the compressor per some TSB. I removed them both and reinserted them firmly, lowered it, replaced fuse and started it but nothing happens. However when I push the inflator button it always runs. I'm stumped!

 

[northcreek]

Jayman

Another possibility is the VSS(veh.speed sensor),the compressor monitors that for possibly? not allowing the system to change vehicle attitude above a predetermined speed.
Still I'm thinking compressor processor board which is probably integral to the compressor and not replacable.I hope I'm wrong because as you know they are alot of $$ or $$$ in Canadian funds...Mike.

 

[Jayman]

LOL you know it us Canucks pay through the nose.
Not so sure the VSS comes into play because it wouldn't inflate when stationary as it usually does.
On the other hand I was moving it outside for a moment to pull mine in the garage and as I left it running and went to mine the compressor began to run! Its not all the way up yet (it took some time to come up after the air spring install) but I'm optimistic for now. So clearly it appears to be intermittent for some reason. Perhaps A new compressor is in order... I really don't want to go through dealer diagnosis - maybe I'll get lucky and it will continue to run? Ya right!
Jay

 

[northcreek]

Jayman

Not so sure the VSS comes into play because it wouldn't inflate when stationary as it usually does.

I'm pretty sure that the inflate circuitry operates outside of the logic board circuitry,in other words it's just a switch on/off deal with some protection schemes built in.
Those intermittents can drive you crazy,good luck....Mike.

Jay: Your next $$$ might be better placed here> http://www.ebay.com/itm/2002-Chevy-...EM-BOOKS-/160732260201?pt=Motors_Manuals_Literature&hash=item256c63a769&vxp=mtr

 

[Jayman]

May have something here. Pics didn't post in order (follow by numbers). The part number is 15183676. Think I may try this as its fairly cheap.

REAR OF VEHICLE SITS LOW, ELECTRONIC CONTROLLED AIR SUSPENSION (ECAS) COMPRESSOR RUNS - WILL NOT LIFT REAR TO OPERATING HEIGHT (REPAIR ECAS COMPRESSOR WITH CHECK VALVE SERVICE KIT)
ARTICLE BEGINNING
DESCRIPTION
BULLETIN CONTENT
TECHNICAL SERVICE BULLETIN
Reference Number(s): 02-03-99-001 GMC: 2002 Envoy/Envoy XL (New Body Style) with Electronically Controlled Air Suspension (RPO G67) OLDSMOBILE:2002 Bravada (New Body Style) SECTION:03 - Suspension Related Ref Number(s): 02-03-99-001
Rear Of Vehicle Sits Low, Electronic Controlled Air Suspension (ECAS) Compressor Runs - Will Not Lift Rear to Operating Height (Repair ECAS Compressor With Check Valve Service Kit)
Some customers may comment that the rear of the vehicle sits low and will not return to normal operating height. The customer may be able to hear the ECAS compressor running.

 

[northcreek]

But....

If I'm reading this correctly the TSB says that the compressor runs but it does not lift the vehicle.Your problem is that it only runs from inflator or sometimes otherwise.I'm having a hard time thinking that the valve is the cause.....:m2:..Mike.

 

[06Denali1010]

Air Compressor/ air bag suspension

I would recommend using a spring conversion kit. I had the same problem with the bags in my 06 Denali and bough a kit with springs & shocks for $300 on ebay. The dealer wanted $750 to place the bags and in time the compressor and/or air lines may need to be replaced as well for an additional $700 depending. You can install the kit yourself with simple tools and a spring compressor kit.

 

[Jayman]

Okay maybe this will shed some light on the situation.
The new bags I installed - only the passenger side is inflated. The driver side has no air in it at all yet it is still level at the back, just riding low. I checked the air line and its secure. What might cause this? Compressor lines are tight too.
All feedback will be greatly appreciagted regarding this specific issue.

 

[Jayman]

So after doing more reading I decided to use my garage compressor and inflate through the service port in the rear. Both bags are now inflated and sitting nice at normal ride height. I turned on the truck compressor from the switch and the pressure reads about 75lbs so it seems to be putting out enough pressure.
If it won't run and do its job from this point I can only assume there is an issue with the compressor putting out to the springs themselves. I may have to bite the bullet and invest in a new compressor unless you guys have something for me?:suicide:

 

[northcreek]

Jayman

Jay, you are in denial and no amount of tweeking is going to save you from buying a new compressor.Yes it will run and pump air but, the brains of it are toast.
I have an 07 and while replacing the bags(which was probably a waste of money) I decided to check out the compressor.For a 5 year old truck it was pretty rusty.Most is aluminum or plastic but, the motor is steel and I could see where given a few more years there would be pin holes to let salt laden water into the internal workings.I sand blasted primed and painted it to add some life.I still believe that your circuitry is fried.....:m2:Mike.

 

[Jayman]

Mike I suppose "denial" is a perspective which can be considered...
My process is probably different than yours, but I've pretty much come to that conclusion without "expert diagnosis". I could have saved money on the air springs, but all the same, who knows when they would eventually fail.
On another note the compressor won't run on its own while the truck is running and already the air has leaked out of the springs for the most part so I'm pretty much aligned with a new compressor. The information I posted above was in the hope that some would see what's been done and conclude which repair was actually required as opposed to just throwing parts at it.
Thanks - I'll let you know if its solved.

 

[hbokc]

D-Height and Jounce Bumper

I will be replacing the airbags on a 2005 Envoy this week end, the manual says to ' position the axle so the distance between the top of the axle tube jounce bumper is at the D-height'... But it dosn't say what D-height is, or what the jounce bumper is. Is this measured with the wheels on the ground? or with the axle suspened? I tried to search the old dicussions on this but didn't find this info...

 

[Jayman]

To be honest I had no idea what it meant either. From what others wrote the shocks need to come off at the bottom first which means the suspension needs to hang. I placed my jack stands on the frame rails at the rear. Also in order to remove the springs you'll need the clearance.
Install the springs, bolt on the shocks, lower the vehicle, install the fuse and let it do its thing.

 

[northcreek]

Update needed

Jayman,been awhile,wondering if you have your suspension issues resolved? ..Mike.:undecided

 

[Jspec25]

I had this same problem with my air suspension on the 03 Envoy, quit working a year after i bought it.. I opted for the quick cheap fix. Bypassed the compressor with some push fittings and now I air it up through the port in the rear cargo area. Hasnt failed yet, its been 2 years... Maybe one day I'll come across a good deal on a used compressor and revert it back to normal.... The fix cost me 12 bucks....

 

[Jayman]

Jayman,been awhile,wondering if you have your suspension issues resolved? ..Mike.:undecided

Thanks for the reminder it slipped my mind. I ended up getting a compressor and it was perfect and pumped up immediately. The frustrating part was even though the old one was running, it just didn't deliver the air any longer.
In the end I would recommend replacing it much earlier than I did after the proper diagnosis.

 

[northcreek]

Thanks for the reminder it slipped my mind. I ended up getting a compressor and it was perfect and pumped up immediately. The frustrating part was even though the old one was running, it just didn't deliver the air any longer.
In the end I would recommend replacing it much earlier than I did after the proper diagnosis.

Jay,it might be interesting to drill the rivets on your old compressor and see if water did indeed get into the circuitry and if so,where did it leak in.
Maybe we could all add some life to these things if we knew where the hole in the dike is...glad you are up and running,Mike.