07 XL Denali

[carrmann]

My yukon needs front/rear suspension work badly. The rear air shocks are blown, the front shocks don't seem to work either. 168k miles on the truck.

Is there an easy way to troubleshoot this? How loud is the air compressor(As far as I can tell I've never heard it fire up? I would like to just swap to passive suspension, but I see mixed discussions about this. Is there a way to check if the front electronic suspension is working?

Check suspension light is on, abs light, tcs light all on.

I'm aware of the arnott options and have considered it for sure. I'm worried that there may be wiring problems or worse as this vehicle was very neglected prior to my purchase, so I've considered the strutmaster passive system here for simplicity. I don't mind installing a rear airbag system if i need to for help with towing (I plan on towing a apprx 5k lb boat in the future).

Thank you

 

[swathdiver]

Do it right. A bi-directional scan tool will let you test the various components and pull up the ABS and suspension codes to see what's what. It is very likely time for a complete overhaul. You might need new wheel speed sensors/hubs/bearings too.

 

[carrmann]

Do it right. A bi-directional scan tool will let you test the various components and pull up the ABS and suspension codes to see what's what. It is very likely time for a complete overhaul. You might need new wheel speed sensors/hubs/bearings too.

I have a tech 2
I have a new wheel speed sensor that the tech 2 says it needs. I think it's the pass rear sensor. Would this cause it to not activate?

How audible is the compressor?

 

[swathdiver]

I have a tech 2
I have a new wheel speed sensor that the tech 2 says it needs. I think it's the pass rear sensor. Would this cause it to not activate?

How audible is the compressor?

When you turn the truck on you ought to hear the compressor run through self-tests if it is an OEM unit. If you stand on the back bumper it ought to come on and level out the truck. It's louder than the fuel pump but not overly loud, you have to listen for it.

The rear sensor may throw a code because the wires are disconnected or cut or the tone ring inside the axle came apart and the sensor can no longer read it or was wrecked in the process. That screw on the axle holding the sensor in has loctite on it, it's going to take some muscle and or heat to get loose. The code ought to tell you what's wrong.

Use the Tech-2 to interact with the compressor, turning it on and off and such. My truck has a dumb suspension so am not familiar with those features like the other guys on here are who have Denalis with Z55.

 

[carrmann]

When you turn the truck on you ought to hear the compressor run through self-tests if it is an OEM unit. If you stand on the back bumper it ought to come on and level out the truck. It's louder than the fuel pump but not overly loud, you have to listen for it.

The rear sensor may throw a code because the wires are disconnected or cut or the tone ring inside the axle came apart and the sensor can no longer read it or was wrecked in the process. That screw on the axle holding the sensor in has loctite on it, it's going to take some muscle and or heat to get loose. The code ought to tell you what's wrong.

Use the Tech-2 to interact with the compressor, turning it on and off and such. My truck has a dumb suspension so am not familiar with those features like the other guys on here are who have Denalis with Z55.

Apologies. I was asking if the bad sensor could affect the suspension.

I definitely do not hear the air compressor turn on. I'll go underneath and have someone turn it off/on, to see if I can hear anything. I just don't want to buy a bunch of parts to find out it has a bad computer, or wiring etc and it turn into a nightmare(I'll put in a passive system if it looks like its going that way). I don't mind changing out the shocks/compressor/coils.

 

[swathdiver]

Apologies. I was asking if the bad sensor could affect the suspension.

I definitely do not hear the air compressor turn on. I'll go underneath and have someone turn it off/on, to see if I can hear anything. I just don't want to buy a bunch of parts to find out it has a bad computer, or wiring etc and it turn into a nightmare(I'll put in a passive system if it looks like its going that way). I don't mind changing out the shocks/compressor/coils.

To answer an earlier question, if yours were mine, I would restore the suspension and not convert to plain shocks.

You should be able to use the Tech-2 to turn the compressor on and off and interact with it. @Joseph Garcia

 

[petethepug]

I’m pushing 180k+ on the original suspension in my 09 Esky. Here’s a list of parts you need to rebuild the z55 front struts w/ OEM, guaranteed for life GM struts and the ancillaries. It’s $1.2k.

If you want want to replace all the bushings and control arms with steel or aluminum, it’s another 2-$3h more.

Aluminum / XFE NNBS Front Suspension Rebuild

It's front-end refresh time. I'm fast approaching 180K miles on our 09 Esky ESV. It has the original everything on the suspension. The front sway bar bushings have been replaced with poly recently because they were ready to disintegrate. While looking around at parts I saw that aluminum upper...

www.tahoeyukonforum.com

Here’s the list of all the part #’s from RockAuto. You’d need z55 struts for the Denali. Z95 for the Esky are listed below

You’ve only got to do it once the right way with a lifetime guarantee on factory struts. Jerry-rigging parts and sensors for an economy ride means you’ll be doing it again & again and have your top speed limited to 88mph or override the stability system at your own risk.

 

[carrmann]

To answer an earlier question, if yours were mine, I would restore the suspension and not convert to plain shocks.

You should be able to use the Tech-2 to turn the compressor on and off and interact with it. @Joseph Garcia

Right, I'd like to if that is a feasible option. The height sensors seem to be reading with the tech 2 (the numbers change if I move the vehicle around), so those are working i guess. however all the dampers show 0%, and the compressor does not turn on or off with the tech 2 (it says off, or on but nothing happens). No clicks, nothing. I checked the fuses, both appeared to be fine (swapped out for another one to test and it still didn't do anything).

 

[Joseph Garcia]

Sounds like your compressor may be shot. It is easy enough to remove and visually inspect. Then, you can provide 12 volts to the compressor with test wires and see if the compressor fires up, or not.

 

[petethepug]

My 08 Denali had an amazing ride for sporting 20” rims. The service contract paid full retail for new GM rear air struts and compressor at a Caddy dealership $1200 later. No lifetime parts warranty back then.

RockAuto now has the same factory parts for 1/2 price w/ lifetime guarantee as well as Non OEM compressors w/ overload protection and lifetime guaranteed. GM really cut this Gen trucks a break on active suspension parts.

 

[carrmann]

Sounds like your compressor may be shot. It is easy enough to remove and visually inspect. Then, you can provide 12 volts to the compressor with test wires and see if the compressor fires up, or not.

Ok, I'll get on that. Hopefully it just needs the compressor

Is there a way to test the front setup, or do i need to just buy a pair and install to see what happens?

 

[Joseph Garcia]

Ok, I'll get on that. Hopefully it just needs the compressor

Is there a way to test the front setup, or do i need to just buy a pair and install to see what happens?

As indicated earlier in this thread, a quality bi-directional scanner is needed to test the electronics on these shocks.

 

[carrmann]

The tech2 I said I had earlier, that is the correct one to use?

Not sure what I'm checking to check front shock stuff, the connectors are just laying in the engine bay (not connected at all)

 

[carrmann]

Sounds like your compressor may be shot. It is easy enough to remove and visually inspect. Then, you can provide 12 volts to the compressor with test wires and see if the compressor fires up, or not.

removed compressor. its either original or an old OEM. it did not fire up with direct power.

I'm looking to buy a compressor from a local store. I've got Dorman (which I've heard is not good), or Arnott. I have 2 Arnott options P3242 and P2793. Any idea which would be better or if theres a difference? The P2793 is about $100 cheaper.

 

[Joseph Garcia]

removed compressor. its either original or an old OEM. it did not fire up with direct power.

I'm looking to buy a compressor from a local store. I've got Dorman (which I've heard is not good), or Arnott. I have 2 Arnott options P3242 and P2793. Any idea which would be better or if theres a difference? The P2793 is about $100 cheaper.

Go to GMPartsDirect.com, enter your VIN, go to the Suspension section, and find the compressor. That will give you the correct part number at a competitive price. You can use this correct part number there, and cross-reference it against the Arnott part numbers to find the correct replacement, if they are substantially cheaper.

 

[carrmann]

I temporarily connected a brand new compressor to the yukon. the exhaust valve opens/shuts when commanded. the compressor does not do anything. i have 4 suspension faults, all are faults with the front suspension (short to battery(says passed on both) and circuit open (says failed)for both front shocks, which are not connected).

all 4 dampers show as 0% actuator comm in the tech 2 scanner.

I tried with VSES and without as I'm not sure which one to use in suspension chassis menu.

does it matter if the compressor is fully installed on the chassis, air hoses on etc? does it matter if the rear dampers are showing 0% actuator comm? I dont want to install new shocks until I know the compressor is working (I dont want to damage them). anything else I should check??

 

[carrmann]

Anybody?

 

[Doubeleive]

Anybody?

did your air compressor come with a new relay? if not the relay is strapped/or taped to the main wireharness in the engine compartment typically right below the brake fluid resevoir area, kinda can't miss it, big relay. the compressor should come on anytime it is commanded with the tech 2

 

[Joseph Garcia]

You can also take the compressor out and bench test it with 12 volts. It is easy to remove with 3 bolts (or 2).

 

[carrmann]

new compressor didn't come with a relay I don't believe. I will double check when I get a chance (its pouring right now and I'm on my phone at work)

I bench tested both the old and new one. new one comes on with 12v power, old one does not