GMT900 Factory SUV Suspension Options

[George B]

COOOOOL!

Here's my scandal: Like @S1W99, I want a legitimate "premium" ride. Yes, I want mine along with a 4" drop, but that's beside the point as it's completely doable. The key has to be the shocks. My stock ones were really stiff. When I unplugged them, it was like having no shocks at all. A quick left-right jig of the steering wheel sent it into a sideways oscillation that'd surely put it rubber side up if done at highway speeds. I don't see how getting new factory AutoRide shocks and struts would make the computer stop sending "firming voltage" to the shocks. This is why I'm wondering if there's a reset function to let it know that all is new and well and it's okay to relax and let the shocks do their thing. My thoughts are that new OEM shocks that are inherently more firm than my original worn ones would be even more firm since they'd be receiving the "firm 'em up" command from the controller.

Or, since they seem to still have an operable range of "dingy" to "dirt track car", I'd put my old ones back in and send them voltage from a transformer, controlled by a potentiometer. It'd be like a bass knob on the dash or wherever I put it. Far left would be a safe minimum of firmness for comfy highway cruising. Far right would be whatever voltage the original controller sent to lock 'em up. Anywhere in between would be for moderately damaged country roads with wide curves or corner-carving in the city. It'd be just like the adjustable shocks you have to test drive, then stop and twist knobs at each corner until you're satisfied. Only, these would be controlled electronically and from a single, centralized knob.

Cooool!

But seriously, I winder if the trim set cal resets the learned parameters of the suspension for the shocks too.

 

[George B]

@iamdub, @Joseph Garcia played with this some too after his suspension update. He was seeing different responses from the controller than I was. I thought he might have replaced the module too but I am not sure.

 

[iamdub]

@iamdub, @Joseph Garcia played with this some too after his suspension update. He was seeing different responses from the controller than I was. I thought he might have replaced the module too but I am not sure.

Hopefully he'll chime in.

 

[Joseph Garcia]

To my knowledge, there is no programming within the control module itself to automatically compensate for wear and tear on the strut/shock internal components. I did replace my Z55 suspension control module and programmed it to my VIN. I also replaced my yaw sensor under the passenger's seat, as it plays a major factor in how the control module adjusts the strut/shock stiffness, though that did not need programming, just an initialization.

 

[pwtr02ss]

I wasn't sure where to ask this, but I wanted to tag someone with a Tech2 and with sizable OEM suspension knowledge: @swathdiver

I know the suspension controller can be reprogrammed as (I believe) there was a TSB on the K2xx to fix overly firm shocks. Based on my experiences with my '08, the controller had my struts and shocks really firm. Surely, being an LTZ, it didn't ride like this when new. So, I have a suspicion that the controller firms up the shocks to compensate for wear by factoring age, mileage and maybe even suspension cycles via the ride height sensors. Is this true/partially true? Can the controller be reset or reprogrammed?

Does anyone know how the struts and shocks are adjusted? My guess is variable voltage. Anyone know the scale?

I replaced my struts and rear shocks with oem stuff about 90k miles ago. I've noticed the avalanche has suddenly got super firm. Maybe is where I've been driving the Yukon more but I don't remember it being like that until recently. I'm going to replace them when I lower it and do the front end rebuild but if you discover something other than "age" is causing this, let me know. They don't ride like they're worn out, they e just gotten super firm/stiff it seems

 

[iamdub]

I replaced my struts and rear shocks with oem stuff about 90k miles ago. I've noticed the avalanche has suddenly got super firm. Maybe is where I've been driving the Yukon more but I don't remember it being like that until recently. I'm going to replace them when I lower it and do the front end rebuild but if you discover something other than "age" is causing this, let me know. They don't ride like they're worn out, they e just gotten super firm/stiff it seems

If you're gonna trash 'em, I might take them struts off of you when you lower it.

I might can try compressing one of my original struts by hand, then applying very low voltage and seeing if I can feel any difference. Ramp up the voltage and try again, etc. Or, maybe it reduces voltage to increase firmness. This would at least get me a start as to how it works. I can probably just put my DVOM on the original shock wires to see what voltage the system is already applying.

 

[swathdiver]

Chris, I forgot that I have this! @iamdub

 

[iamdub]

Chris, I forgot that I have this! @iamdub

Oooooh. This looks like some good reading! Downloaded and scrolling...

Thanks, James!

 

[iamdub]

Chris, I forgot that I have this! @iamdub

Suspicions confirmed! 0 to 5 volts

 

[pwtr02ss]

If I replace them, you're more than welcome to them. I was kinda hoping you'd figure out what's making them so stiff all of a sudden and I wouldn't have to buy new ones lol.

It's very possible it's just age and they need replaced though