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GMC Yukon XL and Yukon XL Denali



  • skipjack2skipjack2 Posts: 29
    I just replaced my 245/75/16 Gravestones with Michelin 265 75 16's LTX M/I and my speedometer is reading about 3 MPH fast at 70 MPH. I had this done a a dealership in Charleston, and was assured that they would adjust the computer to compensate for the larger size. I thought I detected some uncertainty about the adjustment, but they said they adjusted it. I checked my speed coming back to Florida on the I/I 95 and at a speedometer reading of 66 I was doing about 69 MPH. It may be that I need more adjustment, which I understand I might be able to do. Has anyone tried this. Where is the adjustment located and /or do you need special equipment to do this? I have the 3/4 LT model, 6.0 engine with Autoride and 410 rear, 4 wheel drive. I really like the Autoride feature and I feel I do get a better ride. I got about 12 MPG at an adverage of 67 MPH on I/I 95 (GPS)pulling a 3200 LBS boat. I had been getting 8.4 pulling an 8000 LBS boat, 14.5 +/- hi way and dismal around town. I hope the tire size up grade will help. (4300 miles on it now.) BTW the Michelins were a vast improvement over the Firestone tires. Both 10 ply. I would like to get the speedometer on with GPS. Any input appreciated.
  • jgmilbergjgmilberg Posts: 872
    Had mine adjusted at the plant I work at, and the dealer should have the same tool. It is called a Tech 2. You just plug it in and follow the directions to get to the tire size adjustments, pick the new tire size and save the change. It worked on mine, paced a car with a digital speedo and everything was right on. I am not sure about it but HyperTech's power programmer is supposed to be able to do it also. Costs around $300 and can do other things too, like get rid of the speed limiter, and change your performance curve. May be worth it, but have read some posts saying something about needing some kind of GM code to change the settings. My '01 3/4 ton Yukon XL is set up the same as yours, and had no problems. The Tech 2 IS a GM designed and programmed computer diagnostic tool and this would explain why the others have posted about needing a code with the power programmer from Hypertech. If you go back to the dealer with your paper work saying that they adjusted for the tire size change, and your speedo is still off, they should fix it. It only takes 15 minutes to do, if the guy knows what he is doing, and can do it in the service write-up area. You must find out if he dealer even has a Tech 2, if not it will have to go onto the big computer in the service bay and I am not sure if it can be done on there or if the service tech knows how. If possible watch them.
  • ssmilesssmiles Posts: 35
    My dealer called me today at 2pm, said my Burb was rolling off the truck into the lot. Will be picking it up tomorrow. Ordered it March 1st. That was a long 8 weeks and 3 days, hopefully worth the wait.
  • ryanbabryanbab Posts: 7,240
    You do not need a "gm" code. It only works for 1 vehicle however. You plug it in the diagnotic plug and it downloads the trucks info (vin model)

    Then you go from their answer a bunch of yes/no questions then program takes 15 min

    Did this to compensate for larger tires (285's on my silverado)
  • dicksiedicksie Posts: 4
    Tell me more about your 99 suburban that you are going to sell. My daughter is looking for one. What color, 4x4? and options. please e-mail me.
  • jffitzjffitz Posts: 3
    I am looking at a used 2000 Yukon XL w/ low mileage and great condition, but it has second row bucket seats, which we did not really want. Anyt thoughts on the positives/negatives of this? What about swapping in a bench: is it possible and how much?
  • ssmilesssmiles Posts: 35
    Took delivery of my 2001 Chevrolet Suburban Z71 this afternoon. It was worth the 8+ week wait. It came equipped exactly as I ordered. I was already aware that the roof rack would not sport the rear facing auxilary lights as Chevrolet originally advertised. After a thorough walk through to check for problems before leaving the dealer, my wife found that the seat belt in the middle seat of our second row bench was installed backwards. The dealer corrected this within 15 minutes and we were are on our way home. It was built in Silao, Mexico and came with 17" Goodyear's.
  • jgmilbergjgmilberg Posts: 872
    The only things I can come up with for 2nd row buckets are as follows:

    Easier access to the 3rd row for kids.

    Open space between the seats when folded down, a big thing if you want to haul long stuff, like 2 X 4's
    Loss of passenger carrying capacity.
  • don4341don4341 Posts: 69 now lists the 2001 Shop Manual as available.
    Price = $120.00 + $6.50 to ship.
    Land Line = (800) 782-4356
    Fax = (313) 865-5927
    This is Irv. covering for Brother Don 4341.
    Good health to all.
  • moss6moss6 Posts: 12
    Hypertech programmer is the only way you will be able to reprogram for a tire size change; it is done by tire diameter and is accurate to 1/4" increments. The tech 2 tool will register on the link hook up but will not actually adjust any parameter on the actual trans. or speedo profile.
  • rhanson3rhanson3 Posts: 69
    I have read so many conflicting threads on this for such a simple idea. Even the 3 dealers I have talked to don't have an idea. I am still wanting to make the corrections for the 265-70-17 Denali wheels I put on my 2001 Yukon in place of the 265-70-16 stock sizes. What do you mean the tech 2 will register on the link but not actually reprogram?
  • jgmilbergjgmilberg Posts: 872
    It does work! Itold you that's how I did mine, a guy did it in the parking lot at the GM plant I work at. It took10 minutes, and it is right on the money. I have paced a few cars with digital speedos and they all match mine. The changes have to be saved form the Tech 2 into the memory of the trucks computer, if not the change will not take. It clearly askes you if the tire size is correct, answer yes/no, and it will or won't change the settings. You do the change under the TIRE SIZE CALIBRATION menu. The menu title alone tells you that the tool can do it.

    Here is a little help to make sure you really need to re adjust your speedo, it explains how to figure out tire sizes and compare them to each other.

    drb2002 "MY2001+ GMC Yukon Denali/Yukon XL Denali" Apr 30, 2001 3:19pm
  • jgmilbergjgmilberg Posts: 872
    Do you mean that if I bought the power programmer to use on my Yukon XL I can't use it on my Silverado, with the same engine? It actually stores the vin and will only work in that vehicle?! If so it's kind of a rip off in my opinion.
  • ryanbabryanbab Posts: 7,240
    "It does work! Itold you that's how I did mine, a guy did it in the parking lot at the GM plant?"

    A guy in the parking lot? How big was this machine. My dealers tech 2 is connected to a pretty large computer.

    Yea the HPIII wouldnt be good for your silverado. Only way it would work is if you set all the settings on the XL back to stock. Then you could use it on the rado but the XL would have any of the programs anymore.

  • levine2levine2 Posts: 1
    I am picking up my new 01 1/2 Ton 4x4 LT on Saturday that I ordered end of March. I wanted to buy the CD changer shown in back of the Suburban catalog from my dealer to add to the truck when I pick it up. The dealer discouraged me telling me that other customers have not been happy with this changer. The recommended I got to a stereo place and have one installed. This is a small family run dealership so I respect their opinion but I am curious what experience other Suburban owners have had with the GM CD changer. I would really like to get it since it looks like it has been engineered to work with the stereo and fit into the center console.
  • m5stevem5steve Posts: 4

    Just picked up my GMC Sierra C3 a couple weeks ago. Really love the truck, but I have two issues that neither my dealer, or any C3 owners I've found (at forums) have seen. The C3 is basically a Denali pickup, so perhaps you've seen these issues and can let me know what the fix was.

    The first is the steering wheel mounted stereo controls. The mute button doesn't work. Press it, and the radio/cd/cassette is muted, but only for a couple seconds, then it comes back.

    The second has to do with the lumbar support. Mine seems to pump itself up all the time. For me, the most comfortable seating position is with the lumbar and side bolsters completely deflated. But every time I get in the truck, I have to deflate them again.

    Any ideas??
  • ryanbabryanbab Posts: 7,240
    those gm cd changers are expensive

    they wanted $600 for a 6 disc installed in my truck.
  • rhanson3rhanson3 Posts: 69
    Did the Tech 2 also correct the transmission shifting points? I am switching from the factory 265-70-16 to the Denali wheels 265-70-17. Someone told me that the Denali size is not programed into the tech 2, that I should go with a 265-75-16 which is programed in the tech 2 and is less that 1/2 of 1% different. Comments and any further details that I can print out and give to my service rep to read. Your help is greatly appreciated. Bob
  • ryanbabryanbab Posts: 7,240
    Does gm offer the combo


    on any of their vehicles? (i am not quite sure)

    If the answer is yes then they can reprogram it. If they say no tell them to call technical assistance. They will help them out

  • dfwk2500dfwk2500 Posts: 68
    If the computer adjusts by 1/4 inch increments, I'm confused. Presumably that is 1/4 inch in diameter. My YXL came with either Steeltex R4S or A/T depending on if you wanted off road tires. Either set is 245/75/16 and dealer said no change to system regardless of which tire you get. Diameter new is 30.4 for the R4S and 30.6 for the A/T -- 1/5 an inch difference. Since the tread depth is 14/32 on the R4S and 16/32 on the A/T, when worn out, both tires are the same diameter -- 29.65. Take the off road A/T's for instance, the margin of difference will be from 30.6 to 29.65 over the life of the tire, almost a full inch. Presumably if I change my tire size and the overall diameter difference is less than an inch, is there really a need to adjust the computer? It can't be that exact if the 245/75/16 tires from the factory are slightly different and the size changes almost an inch as the tires wear out. Am I way off base with this approach? I really don't plan on doing anything more than going up to 265's.
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