GMC Yukon Cruise Control Problems

jan63

I have a 2007 Yukon. My cruise increases from 3 to 7 miles per hour depending on the slope of the decline. I have taken it to the dealer and they said that was in normal range. I have had a 2002 Tahoe that never had that issue as well as I rent veihcals of all kind with out having to break on every decline to avoid speeding. Has anyone else experienced this and has any dealership repaired the problem?

ahightower

I have an 05, so maybe it doesn't apply. But I will concur that it, and every other car I've had, will downshift and use engine braking to maintain the set speed downhill. It'll increase some, maybe 3-4 mph before anything happens, but it does do something.

kvfallon

I have a 2007 Yukon XL Denali and have a problem with hesitation while trying to accelerate while going uphill. This occurs mostly from a cold start. I also have problems with the cruise control functioning properly; on the highway while accelerating it will jump and kick in violently and it also "jumps" and accelerates too much while on the the downside of a hill. Does anyone else have these problems and what did you do about it? I have taken it to Lou Sobh GMC in Atlanta and they say there is no problem.

jan63

I have taken my to the Chevy dealer where I purchased my GMC 2007 (used) with no luck. They said it's common and due to fuel savings it can fluctuate. I was not satisfied with the answer so I emailed GMC. That was no help. GMC called the dealer and then called me back saying what the dealer already told me. ????? I am taking it to a local GMC dealer next week. I gained 12 miles down hill - it is as if the cruise kicks out on the decline. And on the incline waits until it is below the speed and had to really accelerate to meet the set speed.

carclo

My brandnew (412miles!) GMC 2500 pulled my 4 horse trailer perfectly up a winding steep grade to my favorite trailhead. But the trip back home was wild. In LOW, I had to go to my brakes more than every 10 seconds to keep my speed down. That trailer pushed me ever-faster down that grade. Either the Low gear is not low enough, the Vortec engine doesn't allow enough compression for braking, or I need a different ratio. I have a 3:1.. but my dealer says that likely the 4:1 will pull uphill better but NOT give me more braking! Anyone have any comments? Any solution? My old 1991 GMC would crawl down that same hill in Low. I think the cruise control problems are related to a downhill engine/gear braking problems.

colonelz

My 2007 Denali XL will downshift too quickly when going up the slightest incline, sometimes even two gears - increasing revs unnecessarily and wasting fuel. While I know a six speed has closer shift points, I just do not think this is normal, especially on gradual inclines. Anyone out there have similar experience or know of a GM fix in the works? Other than that, it's a great vehicle (so far).

brewboy

I have an 2007 Denali build date March 2007 and it does the same thing. According to some on another forum the best solution is to reprogram the engine and transmission with a Diablo Sport Predator programmer ($300. I have been told thats what GM did to the Escalade when they set up the 6.2L L92 engine for 403HP as opposed to our 385HP.

colonelz

Thanks! Does your Denali downshift even at the slightest incline? I have not noticed the problems going downhill like the others have, but the uphill, or better defined, up gradual incline shifts drive me nuts!

Do you have a link the the other forum? Also, will applying the programmer void the warranty?

brewboy

I find it actually tries to hang on to 6th gear on slight inclines and then actually engages in what GM calls "Busy shifting" they put out a TSB on that with a fix you may wish to investigate.

Document ID# 1892711 6L80 Auto Transmission Busy Shifting, MIL Illuminated, DTC P1751 Set (Replace Control Body Spacer Plate) #07-07-30-002-(01-30-2007)

Its says vehicles built before December 2006 but I think I still have the problem.

The programmer plugs into the UDC connection under steering wheel and when you take vehicle for service you just re-enter the OEM program and the truck is back to factory settings.

The other fourm is The Chevy Avalanche Fan Club

colonelz

Thanks,
I will get with my local GMC dealer who seems to really want to please their customers. Will keep thread updated!

colonelz

Took a trip this weekend (about 200 miles) in the 2007 Denali XL and noticed a improved (although not perfect) cruise control performance. Very little downshifting while going up gradual grades, 17.2 mpg with a/c on, traveling about 68-75 mph.

Difference??? The only thing I did was increase the tire pressure (20 inch rims) from 34 to 38 psi.

yukon123

Does anyone know how to fix the cruise control for an 07 Yukon Denali XL? It only works once in awhile. It is almost like it doesn't recognize I pressed the button. Has anyone else had this problem? Thanks!

keithb79

I have the identical truck and am having the identical problem. Haven't taken it in yet, but it is really annoying.

Have you found anything out yet?

yukon123

No I haven't taken it to a dealership yet. Tried to search the web for an answer first before I have to pay $80 just to diagnose the problem.

snorris

Keith, Have you found anything out on your cruise yet? I have a 07 Yukon 4x4. The cruise will shut off sometimes, other times it will not reset after you hit resume, other times it will not set at all. It just does it's own thing. Gm say's that can not find out what is wrong with out an error code. I told the dealer mech to take it for a weekend, plug in his diagnostic unit and get the code when it went out. He say's it only went out once and he could not get a code. Then the dealer said they just got a service bulletin on the cruise and the frt passengers window working intermittenly. They put in the new code told me it was fixed. I drove less than an hour and it is out again. I have had nothing but problems with this Yukon. Next step is to talk to the dealership owner and tell him it is time for them to step to plate and take care of it. :lemon:

rsht

Have you checked your brake light switch, if its adjustment is too far/sensitive to the brake pedal's movement? That may be a possibility... just a thought.

snorris

Could you explain a little more in detail. I will call the dealer and ask them. I'm all so going to take it to a independent mechanic. Thanks for the tip.

rsht

Any time if you step on the brake pedal, it will not only turn-on your brake lights but also disengage the cruise control on your vehicle (if its engaged at the time). On our particular model, the brake switch is installed next to the brake pedal mechanism as with most vehicles under the dash area; however, the switch also interfaces with (or a component of) the BCM (Body Control Module) interfaces with the Cruise Control system. So, you may want to ask you Service Tech to check the brake switch for proper installation/adjustment as a diagnostic starting point... In case your service department tells you there is nothing they can do without some sort of Trouble Code, ask them if they can re-program the BCM for you, hope that may resolve the problem.
Good Luck!!

snorris

Thanks for the info. I will be over there next week and will see the dealer. :confuse:

yukon123

Thanks for the information. I will look into it. The problem is getting the cruise control to work in the first place. Sometimes I can press and press the button and nothing happens (before you ask I do have the other button pressed for cruise control) and then other times it will just work. Also when it does work, which is rarely, if I hit a bump in the road it will turn off. To me it seems like maybe a loose wire connection that works when the wires are together but bumps or certain movements might disconnnect them. Could this be a possibility?

snorris

I have the exact same problem you do. Read msg #19 from rsht and that will explain the brake/cruise. I was refered to a very good mechanic who told me the same thing and that if it is set wrong it can interfere with the cruise. He told me next time mine went out to tap the brake,pull up on the pedal with your toe,tap the side of the pedal etc then try the cruise. I did this and mine came back on! when I hit resume. Then while it was on I pulled up on the brake pedal with my toe (just a little bit) let it go and the cruise went off, hit resume and it came back on. He also said when it goes off, traffic permitting, pull over and and check your brake lights. Sometimes they will be on because of the brake misadjustment and that will lock out the cruise. Next stop is back to the dealer, tell them to check the system and reprogram the brake control modual. Will let you know the out come. Hope this helps.

snorris

O.K. looks like the intermittent cruise problem is fixed. Changed the brake switch and the brake sensor switch. Hope this helps you other guy's having the same problem. It's a shame the customer has to do the leg work, research etc and tell the dealer what to look for. Seem's like if there is no error code etc they are clueless. Oh well hope this does it.

yukon123

I took the Yukon to the dealership 2 days ago & found out the same thing. They changed the brake switch and sensor & $125 later my cruise control finally works! I figure the $$ it saves on speeding tickets will pay for the fix. My dealer did actually find the problem & solution quickly.

snorris

Glad yours works now. Hope the other people have the same out come...Sam

gmcglenn

Same problem with 2007 Denali Cruise. Works sometimes, most times not. Decided to change the brake switch since the slightest movement of the brake pedel would shut down the cruise. I wanted to have a look at it, so I decided to take it out.
Switch is attached to the brake pedel and connects to the rod going to the master cylinder. Remove one bolt which holds the retaining clip in place. Defeat the interlock on the retaining clip and slid up to remove. Slide the switch assembly off the post connecting to the master cylinder rod and the switch is free. Unplug the wiring harness you can get out of that uncomfortable position with the switch in hand.
What I determined was that the switch has a somewhat friendly user removable access which exposes the contacts within. Defeat the four plastic release tabs (tow on each side) and pry the cover off. Inside are one set of open contacts with two contact points, and one set of closed contacts, with another two sets of points. The open contacts close when the brake pedel is pushed, completing the circuit for the brake lights. The closed set open, causing the cruise control to disengage.
Everything looked as good as new, but I decided to clean the closed set of contacts. Using electrical contact cleaner and a gun barrel cleaning patch I wedged the contacts open, inserted the solvent soaked cloth and let the contacts close. Then pulled the cloth out to clean the face of the contacts. There was a hint of black residue on the cloth, so I repeated until the cloth came out clean.
I snapped the cover back in place, reinstalled the switch and the cruise control has worked flawlessly ever since.
I my case, a new switch would have fixed the problem, but the contact cleaning is a pretty simple process and saves a trip to the dealership!

rrayw747

Thanks for the step by step. It worked with my 2008 Yukon, but now I've got trouble with the door locks. rrw

gmcustsvcsarah

rrayw747,

Sorry to hear that you are experiencing some difficulties with your door locks - if you were planning on visiting a dealership to get this looked into, please send an email to socialmedia@gm.com and let us know. We're available to assist in whatever way we can!

Best,
Sarah
GM Customer Service