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GMC Yukon Denali/XL Autoride Suspension



  • roo9roo9 Posts: 5
    Your info has certainly gotten me started tracking down my problem. I have tested from the red wire on the truck side of the connection at the compressor and have 12 volts - would this indicate that the ALC relay is working?
    I also tested the compressor and it runs with 12 volts to it. I also checked the resistance of the exhaust solenoid and got a constant 24 ohms.
    But my compressor does not run. I don't know what to look for to check the Level Sensor at teach wheel - where are these exactly? Thanks.
  • roo9roo9 Posts: 5
    I drive an 03 Denali xl. The compressor is not actuating at all. I have checked the red wire at the connection to the Compressor and have 12 volts on the truck side. Does this indicate that my ALC Relay is ok?
    I have also checked the resistance in the Exhaust Solenoid and have a constant 24 ohms. The Compressor runs with 12 volts put to it. The fuses are good.
    I do not know what to look for relative to the Level Sensors at each wheel - where are they and what do they look like? Thanks.
  • mag44mag44 Posts: 32
    Sorry for the slow response, been whitetail hunting for the last week.
    The level sensors are easy to see from the each wheel well while kneeling by the tire, You will spot the bolt that holds them on and the sensors themselves have a linkage. You can disconnect each one and rotate the sensor, you will hear a very faint beep by the compressor if they are working.

    I haven't heard a lot of sensors being bad but it's worth the check.

    I may before I went through removing each one, just for fun, jumper the blue and white wires from the exhaust selonoid on the truck side of the connector. I may also want to check the continuity of the wires going through the connector just in case one of the wires may not be seated properly in the connector.

    See what happens with that.

    I am not sure but can photos be posted here I can't seem to do it.
  • steverstever Posts: 52,683
    You can post photos here using the Img button below the posting box. You need an online place to host them - the URL of the photo will go in the spot that the button opens (after the img scr = part). Then you click the Img button again to "close the code".
  • roo9roo9 Posts: 5
    I did the Blue/White jumper and the compressor did not start. Can I buy just the pressure switch?
  • mag44mag44 Posts: 32
    I have not found a place to just buy the replacement pressure switch.

    I had another thought if you want to try another couple test.

    If you want to try this one first or do the second one first it's up to you, you could jumper the 5 V wire on the pressure switch (orange) directly to the signal wire (green) to see if the compressor kicks on bypassing the pressure switch.

    If it does, then..

    Inside the exhaust solenoid is a small plunger that when a voltage is applied to the solenoid it activates a magnetic field and moves this plunger. This may be a long shot but the plunger has a small (I think orange) oring and even though you are getting a good ohm reading it's possible that the plunger could be stuck!

    This means you would need to cut off the epoxy and get inside the solenoid which only takes a minute if all checks out then put it back together.
  • pablo14pablo14 Posts: 1
    Hi I just purchase a 2008 Denali I dont know much about the Autoride suspension, just what ever is in the manual. It just seems that the rear supension is lower that the front one and the truck looks unlevel even when its turn on, and I was wondering if there is a bottom or switch in the truck that would level it manually, if not do any of you know if i can have it lift with a special kit that would keep the auto-ride working still?

  • roo9roo9 Posts: 5
    I did end up buying the replacement compressor and that solved my problem. That was a few miles ago and now the shocks have started to leak. I did buy the Arnott OEM replacements. How do you get the old air line off of the existing shock - I am afreaid to pull too hard.
  • Each line is held onto by metal clips. Grab the clips and twist them 1/4 turn around the hose itself. Kinda like a quarter turn lock. Maybe someone can explain better than me...
  • roo9roo9 Posts: 5
    Thanks for the help. I had slready gotten the clips off, but the line had some rust formed behind the small flange and gasket which was up inside the fitting. It just would not come out untill I lubricated it with some PB. Thanks for following up.
  • I'm having problems with my air ride suspension from a 03 Denali. So far I got a new compressor, new relay and all 3 fuses are working fine, I try to test the sensors but I only heard a little bip on one front sensor and the rest didn't do anything. Is there any way to test the ESC (electronic suspension control) please help!!!
  • Is there a video tutorial out there anywhere that would walk through the process of replacing the autoride shocks? Just the shocks is all I'm looking for.
  • swearnswearn Posts: 1

    I purchased new rear shocks and compressor for my 2005 Yukon xl Denali from Arnott. I checked the compressor before I put it on and it checked out fine. I changed out the shocks and compressor and rebuilt the drier unit and plugged everything back in. However, now that it is installed the compressor will not run and could not clear out the error message on the dash. Still says Service ride control. Here is the list that I have done.

    Changed relay for the system.
    Changed *1 40 amp fuse
    Changed 30 amp RTD fuse
    unhooked battery for 30 minutes.
    Cleared all error with controller.
    Rechecked all connections.

    Does anyone have any other suggestions?
  • rshtrsht Posts: 277
    edited July 2011
    The one thing I did not see you mention specifically is the ECM, did you check the connection at the ECM?

    As far as "Relay", I have a 2007 Denali it has 3 ALC relays, 2 sitting side-by-side in the fuse box in the engine compartment with the 3rd relay cable-tie to a bundled wires just below and outside of the fuse box. Does your particular year has only 1 replay, or you have identified a bad relay so replaced the one..?

    BTW, I believe there is a difference between "Service Suspension System" (compressor and air leak related) and "Service Air Ride Control" (Electronic control function related)... You may check with your local GM Service Department to be sure.
  • dbetheldbethel Posts: 14
    edited August 2011
    This thread was most helpful for me to troubleshoot my 2002 Yukon XL Denali auto ride system. I ended up buying two remanufactured OEM GM rear shocks from Arnott to replace my leaky originals and the Arnott compressor "kit" to replace my burnt out compressor (from running constantly because of the leaky shocks).

    The installation of everything was super easy and the included air dryer rebuild kit was much needed as my original dryer material was very wet. Everything worked fine for about a month and then last week the compressor failed to come on with a heavy load on the the hitch.

    When I grounded the light blue wire going to pin 86 of the automatic level control relay (attached to the engine side of the underhood fuse center) the compressor would run. This told me that the problem was that the Suspension Control Module (SCM) was not activating the relay by sending a low (ground) signal from output A10 C2 to pin 86 of the relay coil.

    Further investigation discovered the cause which was an open coil circuit (white & blue wires) on the new Arnott exhaust solenoid which is part of the Arnott compressor "kit" assembly. The SCM can detect this open circuit and it will not activate the compressor relay when it detects an open exhaust solenoid coil circuit. However I had no fault messages or indicators displayed on my dashboard.

    I read earlier in this thread that the exhaust solenoid coil should normally read about 24 ohms of resistance and that shorting this circuit by temporarily connecting the white and blue wires together would "fool" the SCM into thinking that the exhaust solenoid was functional which would result in the SCM activating the compressor relay.

    I tried this with the load on the hitch and just like someone else posted earlier, the compressor would come on only for just a couple of seconds and then stop. Each subsequent off and on cycle of the ignition circuit would trigger another very short activation of the compressor relay.

    I am wondering if the non functional exhaust port operation causes some other issue perhaps with the pressure switch that prevents the system from running longer. Does anybody have an opinion on this? I guess that when I get the warranty replacement Arnott compressor / exhaust solenoid valve assembly later this week I will find out.

    Thanks to all of you for educating me on the autoride system. Despite the premature failure of the Arnott exhaust solenoid I still highly recommend this company because of the great pricing compared to GM and because of their excellent customer service.

    Dave B.
  • I am wondering how this worked out and if you ever found anything out. I have run all the troubleshooting tips. Checked fuses, relay, and tested the compressor by jumping pin30 and pin 87 on the harness at the relay and the compressor runs. I'm afraid it is the electronic suspension control module. However I have yet to test out the exhaust solenoid which is my next step.
  • dbetheldbethel Posts: 14
    Arnott replaced the compressor assembly (which contains the exhaust solenoid) and my auto ride system is now working properly again.

    In my case it was a bad (open circuit) exhaust solenoid coil that was causing the computer to not start the compressor.

    I would check your exhaust solenoid coil resistance. You should read somewhere around 24 ohms.

  • THE IS IN YOUR FRONT SHOCKS. how many miles vehicle has, and do you feel the cracks in the road? I replaced my front as well with the replacement sencers and that took care of the error message. The error message is always in the front shocks .Good luck.
  • I have a 2007 Denali XL and about a year ago, I had a service light turn on. After taking it to my local GMC dealership, they advised me that I needed to replace my right rear shock. After hearing the price they were asking to replace the shock, I decide to take my problem to my mechanic who has been servicing my car for years. He replaced the shocks for half the cost.

    After several months, I started hearing a hollow sound every time I would go over a bump. I did start noticing that my ride was a little bumpier so I took it back to my mechanic.

    For the past week, he has been unable to locate the problem. He has check all four shocks which he stated were still good. After reading these posts on the air ride suspension, I realized that I no longer hear the noise the compressor usually makes. Do you think that this is causing the hollow sound noise?

    Please help

  • I am not sure about the "hollow" sound but my 2002 Denali XL rode poorly especially when towing with a bad compressor & leaking rear air shocks.

    It is easy enough to test the system. Simply put a load on the rear of your truck with the ignition on and within a few seconds you should hear the compressor and see the rear of the truck raise.

    If the compressor does not run with a load on the rear of the truck you will know how to troubleshoot it by reading the previous pages of this very helpful thread.

  • gmcustsvcgmcustsvc Posts: 4,251
    I would recommend speaking with your dealer of choice. If they are unable to find the concerns I would recommend asking them to involve Technical Assistance. I hope this helps.
    GM Customer Service
  • This has probably been covered already - but can anyone summarize if its possible to replace the air shocks and beef up the coil springs on the Yukon Denali XL? Towing a 21 foot bowrider boat - not all that heavy but it blew out the suspension apparently.
  • jim334jim334 Posts: 9
    I put Z71 shocks on my Yukon XL and I tow my 23 foot boat with no problem. The boat and truck are level. You have to put resisters in the old plugs that used to connect to the shocks to turn out the service air ride light.
  • Thanks Jim. Your Yukon XL previously had autoride? BTW my air ride is shot now because the compressor is on a lot - but I have no "service air ride" light on? Also did you change your coil springs or leave those? Randy
  • I have a 2004 GMC Yukon XL with autoride. The compressor works and lifts the rear end just like it always did but now I have the dreaded "service ride control" message showing up after driving a few feet every time the vehicle is moved. Would this likely be a problem with the front shocks? Nothing has changed as far as operation or ride but these dash warnings drive me nuts! I just got the "service tire monitor system" message off last month, this vehicle is going to bankrupt me! Any help would be great!
  • From Virginia - I have the same vehicle (2004 Yukon XL Denali/Stabilitrac) with about 120K miles. If you can't hear the shocks leaking then it might very well be a bad front shock. There is a sensor on the top of the shock tower and these connectors get hot, brittle and then fail. One Local tune up shop said that they had to replace these connectors and leads and told me that they could only order the entire vehicle harness which was like megabucks. They were nuts. I went the dealer and they went to Baltimore to get the two connectors. Only one was bad, but I'm sure that the other side would have failed soon anyway. The dealer also had to replace on of the shocks which was less than 1 year old. ($677 parts!). It would not pass the ohms test. When you connect an ohm meter to the leads on the top of the shock and there is no continuity... that's a problem. Arnotte in Fla used to have these shocks new, but right now they do don't have OEM fronts. They have remanufacturered rear shocks at a fraction of the price of new.
  • BTW - If you hear the compressor pump running a lot, you might have a line leak or bad shock. If you let this go, the compressor will eventually fail. Arnotte has replacement compressors at a very reasonable price.
  • MAG44, I wanna thank you for providing this repair info, being an engineer I hate to replace mechanical parts when its something like a simple solenoid repair, this will save me $2000 I have the same fault I found the original workshop manual wire diagram and traced it to this part but didnt go much further believing it was a sealed unit (the solenoid) and would probably not survive the exit route Crush and Extract... now I know this I will go ahead and do this... maybe over the next few weeks or when the weather warms.

    I used to own a Citreone Xantia when I lived in the UK and they had mineral oil suspension system (Auto leveling) the dampers were Spheres with Nitrogen filled bladders, £100 each back then stupid money... anyway I found a small engineering shop that dismantled them, refilled the Nitrogen bladder (or replaced it ) and re fit the mineral oil and bingo! so I gots to wondering if anyone is looking at re-engineering the original OEM shocks for these big trucks... being this is my only wheels for a long time it has to keep running

    Many thanks for the info I'll post if I have any issues
  • You can purchase re-man shocks from Arnotte Industries in Floriday at a fraction of the price of new - You have send in your old ones so that can rebuild them from someone else.
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