ESCM reset?

[lgrw2288]

Just joined the forums after lurking but I had to post this to see if anyone else has come across this: I have a 2008 Yukon XL Denali with Z55 suspension. I just replaced my entire suspension with OEM AC Delco parts (struts and shocks, mainly). Rode and drove awesome up until last week in which my suspension went back to feeling stiff as hell. I unplugged the top sensors mounted on the front struts and the connectors on top of the rear shocks. Drove for a few miles, didn't get any notifications on the dash about "Service Suspension" and the truck rode much better and softer, though there seemed to be more body roll. In other words, it was driving nice and smooth like before. Just for ***** and giggles, I pulled out #2 fuse in the underhood fuse panel (ALC), and when I turn the key on I immediately get a "Service Suspension" in the DIC. Compressor is new, works fine, already tested/diag'd it, etc. I know it's sending something to the struts because of the immediate ride quality change.

Now here's the one thing that made me think back to when this seemed to have started: I recently took my intake manifold and injectors out. I unplugged the battery for quite some time, a few hours if I recall correctly. My question is that is it possible the electronic suspension control module went to some default mode? Maybe some experienced GM guys can chime in here. I don't have a Tech2, however I'm in the process of getting a VXDiag and plan on running a Tech2Win on it. In the meantime, is there some sort of reset to get this back or am I stuck having to get an ALC calibration of some sort? (I read up on Joseph Garcia's build and it was very informative, though I think he went through more hoops than I did)

 

[Doubeleive]

Just joined the forums after lurking but I had to post this to see if anyone else has come across this: I have a 2008 Yukon XL Denali with Z55 suspension. I just replaced my entire suspension with OEM AC Delco parts (struts and shocks, mainly). Rode and drove awesome up until last week in which my suspension went back to feeling stiff as hell. I unplugged the top sensors mounted on the front struts and the connectors on top of the rear shocks. Drove for a few miles, didn't get any notifications on the dash about "Service Suspension" and the truck rode much better and softer, though there seemed to be more body roll. In other words, it was driving nice and smooth like before. Just for ***** and giggles, I pulled out #2 fuse in the underhood fuse panel (ALC), and when I turn the key on I immediately get a "Service Suspension" in the DIC. Compressor is new, works fine, already tested/diag'd it, etc. I know it's sending something to the struts because of the immediate ride quality change.

Now here's the one thing that made me think back to when this seemed to have started: I recently took my intake manifold and injectors out. I unplugged the battery for quite some time, a few hours if I recall correctly. My question is that is it possible the electronic suspension control module went to some default mode? Maybe some experienced GM guys can chime in here. I don't have a Tech2, however I'm in the process of getting a VXDiag and plan on running a Tech2Win on it. In the meantime, is there some sort of reset to get this back or am I stuck having to get an ALC calibration of some sort? (I read up on Joseph Garcia's build and it was very informative, though I think he went through more hoops than I did)

all there is the calibration procedure with the tech2 or tech2 win
park on level ground, truck unloaded, put the tech2 out the window and do the calibration with vehicle vacant, takes maybe 30 seconds and it's done.
if it is a rough ride be sure the relief valve is working on the pump, reach under and feel the shock bladders they should not be rock hard

 

[lgrw2288]

all there is the calibration procedure with the tech2 or tech2 win
park on level ground, truck unloaded, put the tech2 out the window and do the calibration with vehicle vacant, takes maybe 30 seconds and it's done.
if it is a rough ride be sure the relief valve is working on the pump, reach under and feel the shock bladders they should not be rock hard

All that back there is good to go, so no issues there. From what it sounds like I am going to have to use a Tech2 to do this. I was hoping by unhooking the battery and/or some fuses and it would go back to normal. I spent some time undoing the neglect the previous owner had on this, so I am too far invested to just suck it up. I want a like new ride! lol

 

[Doubeleive]

the only other thing you can do is make sure all the shock connectors are on correctly and the ride height sensors are all ok.
the service suspension only comes on when it detects a problem and you need the tech2 or a comparable 2-way scanner to get the code which is not obd

 

[lgrw2288]

the only other thing you can do is make sure all the shock connectors are on correctly and the ride height sensors are all ok.
the service suspension only comes on when it detects a problem and you need the tech2 or a comparable 2-way scanner to get the code which is not obd

all connections are good. In my initial post, I stated that I unhooked all the electrical connectors on the struts/shocks (not the level sensors attached to the arms), got no warnings in the DIC and the truck rode more comfortably. I know that something is telling those shocks to stiffen up, otherwise unplugging all the connectors wouldn’t have made a difference in ride quality. I guess I’ll have to get a pass thru and see what the voltages are and go from there. I might even leave it unhooked for the time being so it doesn’t ride like shit. NC roads are garbage and being on the border of SC doesn’t help either with their lack of road maintenance.

 

[Doubeleive]

all connections are good. In my initial post, I stated that I unhooked all the electrical connectors on the struts/shocks (not the level sensors attached to the arms), got no warnings in the DIC and the truck rode more comfortably. I know that something is telling those shocks to stiffen up, otherwise unplugging all the connectors wouldn’t have made a difference in ride quality. I guess I’ll have to get a pass thru and see what the voltages are and go from there. I might even leave it unhooked for the time being so it doesn’t ride like shit. NC roads are garbage and being on the border of SC doesn’t help either with their lack of road maintenance.

bottom line is you need the code to find out what is wrong, otherwise it is a guessing game or parts cannon.
if you have a good relationship with your dealer service department they may be nice enough to pull the code for you, mine would do it but I have a pretty good relationship with mine.

 

[Joseph Garcia]

If your truck is 2013 or older, invest the ~$350 in an Tech 2 clone. As stated above, without a bi-directional scanner, you will be shooting the parts cannon, and in all probability, you won't get any further than you are now.

 

[lgrw2288]

If your truck is 2013 or older, invest the ~$350 in an Tech 2 clone. As stated above, without a bi-directional scanner, you will be shooting the parts cannon, and in all probability, you won't get any further than you are now.

That's the plan, I have a VXDiag on the way and will use the Tech2Win interface to see what's going on. I'm convinced it needs the ALC recalibration but we will see. Still cheaper than a visit to the dealer. It's a 2008 so they would probably tell me to piss off anyways.

 

[Joseph Garcia]

That's the plan, I have a VXDiag on the way and will use the Tech2Win interface to see what's going on. I'm convinced it needs the ALC recalibration but we will see. Still cheaper than a visit to the dealer. It's a 2008 so they would probably tell me to piss off anyways.

IMO, it is likely not the ALC calibration that is the source of your issue. I'd bet that there is an issue with your ESCM, but a bi-directional scanner will be able to help confirm the source of your issue. I'm not real familiar with the VXDiag unit, but I am assuming that you can monitor what is going on, right on the tool, thus probably no need for Tech2Win usage.

 

[Doubeleive]

most likely has nothing to do with the calibration and is likely a communication or hardware failure somewhere which the code will point to.

 

[lgrw2288]

IMO, it is likely not the ALC calibration that is the source of your issue. I'd bet that there is an issue with your ESCM, but a bi-directional scanner will be able to help confirm the source of your issue. I'm not real familiar with the VXDiag unit, but I am assuming that you can monitor what is going on, right on the tool, thus probably no need for Tech2Win usage.

most likely has nothing to do with the calibration and is likely a communication or hardware failure somewhere which the code will point to.

I'll let you know how it goes. Waiting for this to tool to get to me at the moment. I won't be surprised if the module is crapped out.

 

[Doubeleive]

I'll let you know how it goes. Waiting for this to tool to get to me at the moment. I won't be surprised if the module is crapped out.

until the code is read it literally could be any part of the system, a shock, a connection, a ride height sensor, the pump or even something else.
the system is pretty much impossible to diagnose without a tool

 

[lgrw2288]

Just an update: no DTCs, used the Tech2Win interface. Looks outdated but works nonetheless. I drove it this morning on the highway to my son’s hockey game and it drives ok. Not as soft as I was anticipating it, I guess it’s just the way these things drive. German cars have spoiled me apparently, I had an X5 and an Atlas that drove pretty nice before I got rid of those. Thanks for the input guys.

 

[Doubeleive]

Just an update: no DTCs, used the Tech2Win interface. Looks outdated but works nonetheless. I drove it this morning on the highway to my son’s hockey game and it drives ok. Not as soft as I was anticipating it, I guess it’s just the way these things drive. German cars have spoiled me apparently, I had an X5 and an Atlas that drove pretty nice before I got rid of those. Thanks for the input guys.

it is outdated by 10 years ago

 

[Doubeleive]

you might want to look in the historical data and see what cause the service suspension
the problem could intermittent also if the message comes back on, scan it while it is on.

 

[Joseph Garcia]

^^^x2^^^ Watch the scanner live data while driving. Take another person along who will drive, while you watch the scanner. You should be able to see all 4 shock actuators in progress in real time. You should see measurements between 0% and 100%. The higher the percentage, the stiffer the shock. Mine rarely go over 40%, and typically run at 0% on a smooth straight road.

 

[lgrw2288]

you might want to look in the historical data and see what cause the service suspension
the problem could intermittent also if the message comes back on, scan it while it is on.

Checked that, had no DTCs set. The service suspension light has never come on since I’ve owned it. Only time it came on was when I pulled the ALC fuse, so naturally it isn’t going to have any communication and set a fault. I’m not even worried about it at this point, it’s basically just me having too high of standards on a 15 year old SUV. It’s fine in smooth highway roads, which I’ll be doing next weekend on an 8 hour trip from NC to Maryland. I’ll bring my laptop and the VXDiag just in case.

 

[HACK BLOCK]

ANY UPDATES?

 

[lgrw2288]

ANY UPDATES?

Not really. I just basically chalked it up to expecting too much for a 15 year old SUV, though it does drive pretty smooth on highways and most roads. South Carolina roads are dog shit, so I think I would feel more bumps considering it’s a body on frame. Just took it from Charlotte to Ocean City, MD and then a few weeks later from Charlotte to Nashville, was relatively comfy.

 

[rogercoody1]

If your truck is 2013 or older, invest the ~$350 in an Tech 2 clone. As stated above, without a bi-directional scanner, you will be shooting the parts cannon, and in all probability, you won't get any further than you are now.

What is tech2 clone