Last post on Dec 03, 2013 at 11:06 AM
You are in the GMC Yukon
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GMC Yukon Denali, GMC Yukon XL, Car Safety, Electrical, Engine, SUV
#576 of 585 FOURTH GM Repair
Oct 22, 2013 (10:45 am)
Once again, GM has replaced the pedal sensor three times now. Just got the car back last week and guess what? It happened again. Back to repair a FOURTH time. This is a bunch of BULL. It's not the pedal sensor!
#577 of 585 Re: FOURTH GM Repair [ebonyh]
Oct 22, 2013 (4:52 pm)
My dealer had to build a wire harness from the throttle body to the pedal. Or how ever the wire harness goes. They built a replacement from scratch. Why? Because GM doesn't sell one for replacement! They also replaced the throttle body. But if I had to bet money on what fixed it between the two parts. I would have to say 98% sure it was the wire harness. I think GM got some cheap wires/wire harnesses made in Mexico. And the poor quality of that product would severely hurt their bottom line and they know it. In fact the GM rep. on the 1-800 number was a jerk. And got real nasty after I asked about getting an attorney after my Denali quit and almost put me and my family in a wreck. He was so bad that what ever email he sent to my dealer service writer, really made him upset. As a result my service writer completely took care of the situation. That was like two years ago or more. GM has a BIG WIRE problem they need to own up to it! Tell your dealer to replace or build the wire harness from the throttle body to the gas pedal. Don't fall for the gas cap thing either. Never changed mine and owned our Denali since new in 2003. Hope this helps.
#578 of 585 Re: FOURTH GM Repair [nowwhat2]
Oct 22, 2013 (5:20 pm)
Hey, I need to get my truck fixed. This problem has been driving me crazy! Who is your dealer and how do I get my dealer to understand this info because obviously most dealerships are not on the same page when it comes to this problem. Also when did it get fixed and have you had the problem since?
#579 of 585 Re: Reduced engine power [deanrichardson]
Nov 04, 2013 (8:54 am)
I have had the SAME problem. Reduced Engine Power when the temperature changes. I have had the throttle position sensor changed twice. This last time they changed some wire harness. It is still doing it. More now whether the temp is cool or not. Have you figured anything else out? I am very very frustrated with this ordeal.
Nov 07, 2013 (8:52 am)
I too am having issues with my 07 Yukon.
This may sound crazy...but with all the computerization, maybe not, but has anyone found a correlation with this problem occuring and oil levels?
I first had issues in August. Just prior to getting the dreaded 'reduced power' message, I was getting a "low oil" message/warning. However, dipstick showed proper oil level and I attributed it to a faulty sensor. About three weeks later my wife got stuck on I287. I had not done any research, just figured that a low oil condition would send the car into 'safe' mode so I replaced the sensor and the problem went away until this week.
I was very much up for an oil change and the truck again slowed down on my wife, coincidentally the same time as the change engine oil message came up.
I'm not about to go about throwing parts at this thing as many as you have. I have no justification for it, but my gut tells me its related to some kind of computer/programming snafu.
Anyone else see something similar?
#581 of 585 Something very INTERESTING
Nov 07, 2013 (10:06 am)
Ok, I have a guy that works on my truck out of Broken Arrow, Ok. He is good. As my brother has told me, if this guy can't fix your problem....you pretty much screwed. He is that good. BUT, HERE IS THE INTERESTING SCENARIO.
My Truck is still doing the "reduced engine power", but only at certain speeds. Here is the deal.....when I give it gas and take off and then let off staying at or below 30mph (coasting) it doesn't go into reduced power. ALSO, when I get out of town and throttle the truck up past 60 it doesn' do it either. If I go below 60 and then try to give it gas, REDUCED ENGINE POWER!!! If I stay above 60 the truck has ran good (knock on wood!) BUT, if I try and stay beween 30 and 60, it is a consant headache...REDUCED ENGINE POWER.
So, I called "my guy". I told him my little scenario. He is going to research it a little more. He thinks it could be related to a wheel bearing. Something in the wiring in the wheel bearing/tire area and relating to the signals that are sent to the brain/computer of the truck. Sounds kinda strange but he seems to know A LOT more than I do!!
#582 of 585 Re: Reduced engine power [ebonyh]
Nov 07, 2013 (12:19 pm)
Buy cheap odb2 code reader from harbor freight tools. Hit the clear codes button and it will return to normal, I have an older model reader with a clear codes button. I think it was $39. Keep the odb2 sensor plugged in if you plan to drive the vehicle with this problem as it can be dangerous if you get the "reduced engine power" code in traffic or on the freeway. I almost got rear ended last week on the freeway. Now if I get the code I hit the clear codes button it it returns to normal without pulling over and turning the truck off.
#583 of 585 Re: Reduced engine power [jamika]
Nov 08, 2013 (5:06 pm)
Hello everyone I am a mechanic and i have had this problem in my shop a few times. I have stated here in this forum before there is more than just one cause to this problem.I have found five different fixes.
1. throttle body
2. throttle body wiring harness at the throttlebody
3. the pedal position sensor
4. the pedal position wiring harness
5. the throttle control module
I also know that not all year models have a throttle control module and a replacable pedal position sensor wiring harness.
The gas cap will not fix the problem and using a code reader to just clear the code is a bandaid fix not a proper fix.
I have also found on some vehicles that one or more of these are the problem.The last one i fixed was almost a year ago no more problems.
#584 of 585 Same stuff, different day
Dec 02, 2013 (2:36 pm)
I too have had the dreaded and terrifying "Reduced Engine Power"/"Service Stabilitrack" error. I have a 2007 GMC Yukon XL. It eats oil for breakfast and shuts down randomly. I have a TPS wiring harness on order and will be in tomorrow (12-3-13). I have been told by a GM Dealership that I have to have a computer to reset after switching out the wiring harness. Can anyone tell me if this is true or they trying to pull one over on a blonde woman. I love my Yukon but I'm about to trade it in on a Ford Super Duty with the troubles I've had. Always been a GM buyer but I'm about done with them. Way to dangerous for my family.
#585 of 585 2008 Denali Problem(s)
Dec 03, 2013 (11:06 am)
Just returned from a deployment where my car sat for about 4 months. When I finally got back into it, it drove fine for a bit and then I started getting "service suspension" message and the check engine light was on. I took it into Autozone to get some supplies and had them hook up the diagnostics. Error codes P449 and P045 came up relating to the gas cap and possible solenoids or vapor canister. Basically the gas cap wasn't tight or I was topping off the fuel and some went into the vapor canister... no big deal, just tighten the cap and disconnect the negative terminal on the batt for about 15 seconds and the computer will reset the check engine light. NOTHING addressed the suspension issue. So driving to work this morning and at a stop light my dash started chiming and "stabilitrak disabled", "traction control disabled", and "reduced engine power" came up. Took off from the light and it was rough. I pulled into a parking lot and looked up some stuff on the net. I was letting my car sit while off when I heard a "click" so I tried starting it and the warnings were gone but the check light was still there. But it ran fine so I continued on to work. About a mile down the road, it all happened again as I took off from another stop light. So I pulled over and called a tow truck. I was researching stuff and was going to have it towed to the house where I would replace the throttle body sensor, clean the throttle body, replace it, or whatever. Mind you, it started up no problem. Then the tow truck got there and it wouldn't wouldn't turn over at all! He started telling me it was the starter! So I changed my mind and had it delivered to the GMC dealer service center where I await a diagnosis...
I've read everything from it's a dirty throttle body to the computer needs to be reprogrammed. Anyone else experience this series of issues? I feel like I'm looking down a rabbit hole and I'd rather not fall in regarding the issues you all below have run into. - Vince