Adaptive Cruise not working after lift HELP!!

[AzCoronaDog]

On 9/8/2020 at 6:08 AM, Jbg90199 said:

 

On 9/8/2020 at 6:14 AM, Jbg90199 said:

Thank you for your constructive criticism.  Very helpful input.  Unfortunately, you are incorrect.  Everything does work perfectly with the exception of the speedo not stating the correct MPH.  I can use "Kentucky Windage" of +5MPH to be accurate (as long as I can have one hand free to use fingers) or I can simply look at the Waze MPH on the GPS which is more accurate. The Magnetic ride front suspension works great!  The rear auto leveling air works great!  Zero issues.

 

I need the lift and additional clearance because I actually use my vehicle in areas that require it.  We crossed a river 8 times this weekend with 35 inch tires under water.  I use 4WD at least 2-3 times per week.  If I'm going to spend $86k on a vehicle, I can assure you it will do what I want.  Not "I will do what it wants".  I've got nearly 30k miles on this lift setup so far.  Pulling heavy enclosed trailers, off roading and highway driving.  My tires look barely worn, gets great mileage still and will hurt peoples feelings red light to red light.  

 

 

On 7/14/2020 at 6:58 PM, k-man21 said:

Not sure what you guys expected. You modified your trucks (to the point of illegality) and expect everything to work perfectly? You made your bed, now lay in it.

Wow, pretty harsh, considering you have no idea what you are talking about, at least in my state, where a 7" lift is perfectly legal.

My truck still runs and drives just like stock, thanks to a very high quality lift kit that retains the stock magnetic shocks in the front and air shocks in the back.  By using the correct offset wheels, the 35" tires I chose to use have no rubbing issues at all, and the turning radius has not changed either. 

 

[AzCoronaDog]

I was able to get the Adaptive Cruise Control working again by programming the tire size back to stock as JBG90199 did.

Apparently there is something in the programming for the ACC that does not play well with the tire size change.

 

That means the lift was not the issue at all, it was just coincidence that I reprogrammed the tire size at the same time.

Now that I think about it, the ACC works on hills and curves, so it obviously has a wide range of 'vision' both vertically and horizontally.

 

Now to play with the tire size programming with my new scanner to see if there is any way to keep the ACC and the corrected speed.

 

 

[prorang97]

Awesome guys. I’m going to put mine back to stock through the programmer and take it back to the dealer and have them recalibrate the computer. I have an open case with GM about the issue so this will help them as well

[AzCoronaDog]

Update: 

I used a Hypertech 2000 programmer to update the tire size.  I have a Harbor Freight ZR-Pro scanner that can do the tire size on my Jeep,  but I could not that feature for the GMC.

So I decided to try to contact Hypertech to see if they might be helpful.  I sent an email and got a reply the next day that said I should call them.

I called, and got Kevin in tech support.  In Tennessee.  No foreign accent.  Been with the company for almost 10 years.  Very knowledgable.

He was able to use my programmer's serial number to tell me I had not updated it in about a year. (spot on.)  So he suggested I update it then try setting the tire size again and see if the ACC worked.

I did, but it didn't, so I called back.  Got another great tech on the phone, he setup their update software to grab the data off my programmer, and it sent it to them.  He is sending it to their programmers and they are supposed to get back to me when they have looked it over.  He was pretty certain they can figure it out, as testing their tuning with the ACC is supposed to be part of their QA process.

Hypertech also makes a module that goes inline with the connector that carries the speedo signal, and he was positive that will work with ACC if the tuner cannot be updated.

So I am happy to know that I can have a correct speedo and the ACC!

 

I will post again when I have new details.

 

 

 

[Jbg90199]

10 hours ago, AzCoronaDog said:

Update: 

I used a Hypertech 2000 programmer to update the tire size.  I have a Harbor Freight ZR-Pro scanner that can do the tire size on my Jeep,  but I could not that feature for the GMC.

So I decided to try to contact Hypertech to see if they might be helpful.  I sent an email and got a reply the next day that said I should call them.

I called, and got Kevin in tech support.  In Tennessee.  No foreign accent.  Been with the company for almost 10 years.  Very knowledgable.

He was able to use my programmer's serial number to tell me I had not updated it in about a year. (spot on.)  So he suggested I update it then try setting the tire size again and see if the ACC worked.

I did, but it didn't, so I called back.  Got another great tech on the phone, he setup their update software to grab the data off my programmer, and it sent it to them.  He is sending it to their programmers and they are supposed to get back to me when they have looked it over.  He was pretty certain they can figure it out, as testing their tuning with the ACC is supposed to be part of their QA process.

Hypertech also makes a module that goes inline with the connector that carries the speedo signal, and he was positive that will work with ACC if the tuner cannot be updated.

So I am happy to know that I can have a correct speedo and the ACC!

 

I will post again when I have new details.

 

 

 

Please let me know!  I'm using the Diablo tuner currently but, will change in a heartbeat if I can get everything to work properly.

 

[AzCoronaDog]

Jbg - thanks for the tuner info, I meant to ask which one you used.

Seeing that we used different brands, it makes me think the issue may be on the GMC side.

I will pass this info on to Hypertech, it will be helpful for them to know they are not the only ones with the problem.

Have you tried contacting the Diablo people?

 

Awesome looking 'burb BTW!

 

Edited September 18, 2020 by AzCoronaDog

[AzCoronaDog]

[Jbg90199]

On 9/18/2020 at 10:59 AM, AzCoronaDog said:

Jbg - thanks for the tuner info, I meant to ask which one you used.

Seeing that we used different brands, it makes me think the issue may be on the GMC side.

I will pass this info on to Hypertech, it will be helpful for them to know they are not the only ones with the problem.

Have you tried contacting the Diablo people?

 

Awesome looking 'burb BTW!

 

Thank you!  Same to you on your XL!  I called them when the issue first presented itself and they said they haven't heard of it being an issue from anyone else..  Go figure...  I also noticed that their tunes were for the 6 speed and 8 speed Trans models and mine is a 10 speed.  So, I'm going to reach back out to them today.  I'll let you know.

 

[AzCoronaDog]

4 hours ago, Jbg90199 said:

Thank you!  Same to you on your XL!  I called them when the issue first presented itself and they said they haven't heard of it being an issue from anyone else..  Go figure...  I also noticed that their tunes were for the 6 speed and 8 speed Trans models and mine is a 10 speed.  So, I'm going to reach back out to them today.  I'll let you know.

 

I sent the Diablo info to Hypertech and got a reply that a developer is supposedly looking into it.  I suspect the only fix is going to be the inline module.  If that is the case, hopefully Hypertech will sell one to me at a good price, as it is too late for me to return the tuner. I have only seen 1 other late model Suburban / Yukon XL around here that was lifted, and with ACC being a pricey option, it could just be nobody else has noticed it until now! 

Mine has the 8 speed, I read that people didn't like it much and that the 10 was much better, but it works just fine for me.  I have not had any great desire to try out the other tuning options, but I may get around to it eventually.  I certainly don't really need this 7,000 lb brick to be any faster, but I may try the mileage tune for fun. 20 years ago I would have put headers and an intake and a bigger cam and do everything possible to wring out a few more horsepower, but now I just want it to be super reliable and quiet.  I also have a Porsche 911 Cabriolet for when I have a need for speed, and those extremely competent German engineers did not leave much room for improvement... LOL

 

I took it deer hunting last year just after I put the lift and tires on it, and drove it up a very, very rugged mountain road one day.  When I walked back to it, a couple of other hunters in a Jeep had stopped to admire it. They joked they thought it had been helicoptered in for a GMC commercial because it was so clean and shiny.  Before the lift it looked like a glorified station wagon, but how the wife won't even drive it, so mission accomplished!

 

[prorang97]

Thanks to the both you on the info. I put the factory settings back on the Speedo. I was using and edge tuner. Just dropped the truck at the dealer and hopefully they can recalibrate it after they messed it up the first time. I’ll let you guys know the outcome. Any word on using an inline Speedo calibration tool to fix the issue?

[prorang97]

Ok fellas figured it out. Put the truck back to stock settings and the dealer was able to recalibrate it back to factory settings and the ACC worked briefly. It only worked on low speeds. Once I got up to highway speed, all the warning lights came back on and the ACC turned off. However when I turned the truck off and back on, the lights went away and the ACC would work again at low speeds. Went back to the dealer furiously.... hooked it up to their computer and it threw a code related to the Speedo. The code was said the MPH was off over 9 MPH which is more than the allowable threshold. That is why the ACC would only work in slow speeds. Then I got to thinking, not sure if you guys did a gear change, but I did. Went up to 4.10’s. I have a Edge CTS2 tuner.  So I went in today and changed the gear ratio, but not the tire size.  Now everything works with no issues. The Speedo is off about 3-4 MPH. So in the end, if you guys play with the gear ratio adjust in your tuners, you can get your Speedo close to actual speeds.

[Jbg90199]

11 minutes ago, prorang97 said:

Ok fellas figured it out. Put the truck back to stock settings and the dealer was able to recalibrate it back to factory settings and the ACC worked briefly. It only worked on low speeds. Once I got up to highway speed, all the warning lights came back on and the ACC turned off. However when I turned the truck off and back on, the lights went away and the ACC would work again at low speeds. Went back to the dealer furiously.... hooked it up to their computer and it threw a code related to the Speedo. The code was said the MPH was off over 9 MPH which is more than the allowable threshold. That is why the ACC would only work in slow speeds. Then I got to thinking, not sure if you guys did a gear change, but I did. Went up to 4.10’s. I have a Edge CTS2 tuner.  So I went in today and changed the gear ratio, but not the tire size.  Now everything works with no issues. The Speedo is off about 3-4 MPH. So in the end, if you guys play with the gear ratio adjust in your tuners, you can get your Speedo close to actual speeds.

INTERESTING!!!  The Diablo allows for gear ratio changes as well!

 

[Art Contoni]

I know this is an old thread and glad to see the fixes at the end. I'm wondering if anyone has come up with a relocation bracket or alternative so we can mount the tow hooks. There seems to be a few for Ford applications.

 

You would think GM would want to sell additional options like the tow hooks with ACC.

Edited October 30, 2022 by Art Contoni