Dealer gets error code C0590-04 on my 2009 Tahoe with Z55 air shock system which they say indicates needing a right rear shock. The labor estimate is $265.00 to install the shock and “reprogram the computer”. I asked the service writer if reprogramming the computer meant to just clear out the “service suspension system” out of the system and he said no that the computer has to be reprogrammed to account for the new shock in the system. I have not seen any mention anywhere on the internet of having to reprogram the computer when a new shock is installed. Does anyone know anything about this?
reprograming onboard computer with new shocks
- Thread starter geodavky
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mikeyss
Full Access Member
I just replaced all of my Z55 suspension on my 09 Tahoe LTZ 6.2 and you do not have any reprogramming of any sort. I even had 'service suspension' come on and after replaced my bad compressor, the warnings went away immediately. But the price your dealer is quoting you is really good. However, I would not recommend replacement of just one rear shock.
swathdiver
Full Access Member
The shop manual says:
"Important: Whenever repairing and/or replacing ALC system components, perform the Suspension Position Calibration procedure."
"Important: Whenever repairing and/or replacing ALC system components, perform the Suspension Position Calibration procedure."
kbuskill
***CAUTION*** I do my own stunts!
I've replaced my rear shocks and vompressor in my 02 and the warnings went away. The calibration requires a tech 2 which I didn't have at the time. I don't believe it's necessary.
kbuskill
***CAUTION*** I do my own stunts!
I too have replaced my rear shocks with the Arnotts and have replaced the compressor as well in my '08... never did any recalibration of any kind and no lights on dash.
hmm, I guess I probably need to do this then also but haven't had any problems
Trimset Recalibration If the system is functioning abnormally, performing the Bumpstop and ALC Trimset recalibration procedures may correct the condition. When a system component has been replaced, the Bumpstop setup and ALC Trimset procedures must be performed.
1. Ensure that the vehicle has a full tank of fuel or add sufficient weight to the rear of the vehicle to simulate a full tank of fuel.
2. Place the vehicle on a flat level surface. Ensure that the suspension is in the normal resting position. With a scan tool, perform the ALC Trimset procedure by following the screen prompts.
3. With a scan tool, perform the suspension Bumpstop setup procedure by following the screen prompts. Once the process has been completed, the system should be fully functional.
Trimset Recalibration If the system is functioning abnormally, performing the Bumpstop and ALC Trimset recalibration procedures may correct the condition. When a system component has been replaced, the Bumpstop setup and ALC Trimset procedures must be performed.
1. Ensure that the vehicle has a full tank of fuel or add sufficient weight to the rear of the vehicle to simulate a full tank of fuel.
2. Place the vehicle on a flat level surface. Ensure that the suspension is in the normal resting position. With a scan tool, perform the ALC Trimset procedure by following the screen prompts.
3. With a scan tool, perform the suspension Bumpstop setup procedure by following the screen prompts. Once the process has been completed, the system should be fully functional.
kbuskill
***CAUTION*** I do my own stunts!
I could see going to that much trouble if the ESCM were replaced but beyond that I doubt it's necessary.
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swathdiver
Full Access Member
It appears to me that the purpose of recalibration is to establish the proper ride height with the ESCM with the vehicle full of full but otherwise empty. I think we'll be seeing more Tech2 users in the near future! 
I replaced my ESCM at one point with one from Ebay when I was troubleshooting and never had to calibrate.
It appears to me that the purpose of recalibration is to establish the proper ride height with the ESCM with the vehicle full of full but otherwise empty. I think we'll be seeing more Tech2 users in the near future!
I thought the ride height sensors were supposed to do that. I have pulled an air line before when working on ride height, when I was adjusting the length of the sensor rods in order to get my final height perfect so I was level and my 26's didn't rub, so it would air up to it's final height, and it always just aired until the sensors said it's high enough. It seems like a simple enough system.
swathdiver
Full Access Member
I don't know. Don't have that module in my truck as she has the dumb suspension (ZW7). We'll have to wait for Mike and Wes to tell us what their Tech2s say. Unless your Denali has it?
That's what I was saying. I've replaced all the components in The Beast with no need for a calibration.
swathdiver
Full Access Member
Does The Beast still have that set up? If so, what does the Tech2 procedure actually do? Screenshots?
ivin74
05 NBS Nali
I also have the Z55 suspension, several weeks ago I replaced all shocks the fronts with oem parts and the rears with Arnott (Arnotts have a life time warranty lol) and I did not do any programing, the message error went away by it self. I did notice my ride height on the rear raise up about 1/2" not enought to worry about it.
It does. I'll give it a try today with the Tech 2.
I don't have a tech2 but I also have replaced all the shocks and the pump and it has driven just fine with no issues.
here is the link to what I referenced above, I was just chiming in after the op reported that dealer said it had to be recalibrated, which I had never heard of before.
http://www.underhoodservice.com/servicing-gm-autoride-rear-air-suspension/
here is the link to what I referenced above, I was just chiming in after the op reported that dealer said it had to be recalibrated, which I had never heard of before.
http://www.underhoodservice.com/servicing-gm-autoride-rear-air-suspension/
swathdiver
Full Access Member
your right, I am considering getting one here sometime sooner or later will probably come in handyNot yet!
I remember back when I was trying to figure out why my service suspension light kept coming on, I read about the trimset and bumpstop calibration but nowhere could I find what exactly it did. The error turned out to be the spoofing resistors on my Arnott Shocks which I fixed by wiring some resistors in. Today, since I have a Tech 2, I figured I’d give it a try. And after I did it, I still have no idea what it did. The Tech 2 just says it takes about a minute and then it says it’s done. I tried a different procedure, recalibration, under the suspension menu, but it said I needed to use SPS and I can’t find the SPS menu. I was able to test everything like the compressor, exhaust solenoid, etc. and everything works but I already knew that. If I have any future problems the Tech 2 will sure help me troubleshoot.
swathdiver
Full Access Member
SPS in on the main menu, right under diagnostics. But that is programming from either TIS2000 or TIS2Web. Speaking of the former, I'm still working on it. We had another laptop but it was not set up properly so I'm doing that now and when done will try that copy on it. As for the programming, unless one has TIS2000 or already has a subscription to TIS2Web, I wouldn't bother. Well, maybe, it would be there in the back of my stupid mind, wondering just what it could possibly be that needs doing that everyone gets away with not doing!!! LOL
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