Performing ALC for Z55

[dkad260]

I want to ask this just to be sure, but with the Z55 suspension, you only perform the ALC and not the bumpstop correct?

I have read you perform ALC and bumpstop after replacing components but the bumpstop is only for Z95?

I see on the Tech 2 the bumpstop option is under the Z95 code, but want to be sure about the procedure.

Thanks.

 

[Big Mama]

What did you switch out?

 

[petethepug]

reprograming onboard computer with new shocks

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...

www.tahoeyukonforum.com

 

[dkad260]

What did you switch out?

OE compressor for Arnott compressor. I added the Arnott Z55 shocks awhile back.

 

[Joseph Garcia]

I have searched long and hard for some detailed in instructions on how to perform the Bumpstop Procedure, and I have found nothing.

While you don't 'have' to perform the ALC procedure when changing out the shocks, you should perform it afterward.

 

[Doubeleive]

OE compressor for Arnott compressor. I added the Arnott Z55 shocks awhile back.

just do the alc with full tank of gas, vehicle unloaded and on level surface, drivers window down and stand outside the vehicle with engine off, key in run position
only takes like 30 seconds to do.
basically all it does is it let's the air out and takes a static reading from the ride height sensors and saves it as a reference point.

also not even sure how a bumpstop learn would be performed because even with the air out of the system, the vehicle is not resting on the bumpstops (or shouldn't be)
next time I am at the dealer I will ask the service manager he has a gmt900 escalade

 

[Joseph Garcia]

just do the alc with full tank of gas, vehicle unloaded and on level surface, drivers window down and stand outside the vehicle with engine off, key in run position
only takes like 30 seconds to do.
basically all it does is it let's the air out and takes a static reading from the ride height sensors and saves it as a reference point.

also not even sure how a bumpstop learn would be performed because even with the air out of the system, the vehicle is not resting on the bumpstops (or shouldn't be)
next time I am at the dealer I will ask the service manager he has a gmt900 escalade

Please, please let me know what you hear from the Service Manager regarding the BumpStop Procedure and GMT900 trucks.

 

[dkad260]

Please, please let me know what you hear from the Service Manager regarding the BumpStop Procedure and GMT900 trucks

Same.

I saw it in the Tech 2 if you select the Z95 option but obviously did not want to go down that road.

 

[Doubeleive]

Same.

I saw it in the Tech 2 if you select the Z95 option but obviously did not want to go down that road.

and @Joseph Garcia
so I talked to the service manager at my dealer this morning about the z95 bump stop calibration
he said that when the escalades first came out with the z95 that you could adjust the ride height by 1/2 or so up or down, which is what the bump stop calibration was for
but.... gm quickly discovered that doing this caused premature wear on the components and was causing warranty issue's for gm, so they dropped the option and it is no longer done.
that all said I did read at one point not all that long ago on a "just ask" post that apparently some 3rd party scanners can do it such as a autel, but I have no way to confirm that, just something I read.

 

[Joseph Garcia]

Thank you for looking into this @Doubeleive. VERY much appreciated!! Now, I can get that never-to-find procedure out of my mind for good.

Just another reason why this Forum ROCKS!!