Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

GMC Yukon Reduced Engine Power message



  • So previously I have posted my frustration with the REP and throttle body problems with my 2007 GMC YUKON XL.

    I have also expressed my absolute disgust with GM's response to the many problems that I have had with my vehicle since it was purchased new.

    My vehicle needed a new battery every year until the problem suddenly stopped. The dealership never acknowledged a problem or said what they did to correct the problem. They just kept putting in new batteries.

    When I complained about EXCESSIVE Oil consumption the dealer told me that it was well within the "guidelines". Now that my vehicle is completely off warranty and still going through oil, the dealer is telling me that there is a bulletin out regarding an engine part that malfunctions and it would only cost a couple of thousand to fix the issue.

    I hope that people are reading Edmunds before the ever buy a GM vehicle!
  • I hate to say attorney because that is the very last resort. I went through a lemon law attorney and GM finally agreed to a buyback. Most attorneys will review your case at no charge, but you have to know that you are going to have to buy a new car. GM finally agreed to a buyback through a lemon law attorney. It worked out that I got more than the trade in value. You should call one and depending on the state you live in they may be able to help. I am so happy to be rid of the problems even though I have a car payment now. I feel much safer with my kids. It was worth it for me. Good luck.
  • yukon11yukon11 Posts: 2
    I was driving on the highway going about 75 miles and when all of sudden my 01 GMC Yukon stalled on me showing REDUCED ENGINE POWER, the issue I have with this is I had this problem about 9 months ago and had to replace the throttle body which is very costly and now I'm
    having this issues again not even a year later. Due to the number of complaints I see via e-mail and online, GMC should consider investigating the THROTTLE BODY before someone gets seriously hurt or killed.
  • dob49737dob49737 Posts: 1
    edited July 2012
    do you know where that ground wire clamp was?....I had one attached to a black wire right behind the engine, going towards the engine block in the rear,,,,,i wiggled it a couple of times and the end loop piece just came off....I reattached some wire to the black/white striped wire and attached it to the firewall.....only time will tell.....

    If you can let me know where that clamp was i would be grateful.

    I will report if any further problems occur....
  • Is this problem with just the older models or is it the same way with the newer models as well. Basically I have a 07 with 73 k so I'm out of my bumper to bumper warranty but its going through the whole engine reduced problem every couple of days. Of course when I went to the dealer the supposedly fixed but I don't want to dump any more money in this truck. If this isn't a problem with year 10 and up I'll just get a newer vehicle
  • Update on my 2003 suburban with 250k. No longer my daily driver. Reduced engine power light originally just happened when the weather was sub zero. I live in Austin now so not much cold weather, however the same thing happened the other day, pulled on to the service road and accelerated to 60 mph and then 'ding, ding, ding, the engine went to idle and reduce engine power illuminated. I pulled over(luckily traffic not to heavy) turned off the engine for about a minute and started it up and it ran fine. I'm reluctant to do any repairs because on this forum it seems most people get the throttle body replaced and the same issue continues. I'm still searching for a permanent solution if there is such a thing.
  • cubbearcubbear Posts: 3
    In a previous post I listed all the items I had done. Then I took it to a local auto repair shop. They promised me if they couldn't fix it there would be no charge. Well, they kept it three days and couldn't fix it. True to their word, no charge. When I got it back home it was running really rough and the REP warning was on plus the check engine light. While it was running, I started wiggling wire harnesses. Like magic, when I wiggled the harness against the firewall near the fender on the drivers side down low - low enough I could barely see what I was doing with a flashlight and the engine would start running okay and then rough again. I wiggled it again and it quit. No problem for several weeks - running like new. I drove it to the dealer because the check engine light was still on. They could see the codes but could not duplicate the problem. If it happens again, they said take it in immediately with moving the wiring harness so they could verify my finding. Plus, with all the money I have spent, they will repair it for no charge. How about that!!! I'm hoping it never happens again.
  • gmcustsvcsarahgmcustsvcsarah Posts: 1,964
    We're glad to see that you've been able to find a resolution for the rough running engine concern you had had. All the best!

    GM Customer Service
  • I would be more that interested if this could turn into a class action suite. Would like to be kept informed.
  • i have a 2004 tahoe , im driving in mexico , reduced engine power , abs and check engine lite comes on dash , nobody here can tell me whats wrong , been stuck here for a month , visa running out can you help me truck wont start , battery starter alternator all good , codes ok please i need your help robbie
  • chelsmithchelsmith Posts: 2
    Almost got stranded to with car telling me to service stability track and received reduced engine power message. I have also been driving this thing with basically two gears after getting it back from a shop that repaired a botch family member brake job. It won't change gears until after almost 4000 rpm then after that will not kick into overdrive and runs approximately 3000 rpm at 75mph. I took it to autozone when that started happening and they couldn't find a transmission code only a fuel related one. As of now engine power is fine but transmission issue is not. Seems more electrical than anything because of all the past issues. Dealership wants $50 to run scan and then $125 per hour to fix. This single mom doesn't want to be taken advantage of and would like some help from others on what the problems may be. I've read about possible wire harness problems and computer upgrades that may fix these issues? Do other shops besides the dealerships have capabilities of upgrading software? I'm in north Atlanta area.
  • jen1017jen1017 Posts: 6
    I really can't believe this....I originally posted here back in January with this problem..spent will over $1300 getting a new throttle body and wiring harness, had to take it back less then a month later because the gauges were going crazy while driving on the 6 months later and evening rush hour traffic on the 10 freeway in Southern California my truck 2003 Yukon goes through the reduced engine power abs light flashing, gauges going crazy, weird squeaking noise from the steering wheel, I'm back at the shop trying to find a resolution to the problem and hopefully its all covered under warranty!!!
  • jen1017jen1017 Posts: 6 the module and wiring harness they replace back in January came unwired..the spliced wiring came apart. Dealership that my shop towed it to acts like its no big deal that it happens all the time. I'm not convinced that this problem is not going to happen again, dealership doesn't seem to care and refuse to pay for the original tow to my shop and the tow from my shop to theirs. How is the tow my cost when it was their stupid part and splice job that came apart. I love my Yukon but really starting to think I wont own a 2nd one!!!
  • jen1017,
    We hope everything is going well with the repairs. If we can look into anything, please don't hesitate to get in touch with us at

    Sarah, GM Customer Service
  • Any0ne actuall file a complaint with the National Highway Safety Transportation Board? I just did it would be complaint 10473993.
    Oh has anyone actually tried to communicte with the GM customer service people? I think they are a fake entity they sound concerned but never get back on anything.
  • Good morning rongavaldon,

    When we look into the details of the different situations that the Edmunds community is posting about, we prefer to discuss the details privately as we do need to collect contact information and we handle each different concern on a case by case basis. Not to mention the excellent moderators of this web community would kick us out if we weren't legitimate.

    We can be contacted at if you would like to discuss any vehicle concerns you're having with us!

    All the best,
    GM Customer Service
  • In previous postings I have described my problems with Reduced Engine Power (REP)for the past three years - a summary:

    1- The original problem was caused by a rodent or squirrel chewing on the wiring harness in two different places which, as it turned out, GMC repaired with butt splices
    2- The truck ran okay for several months before the problem returned - the cable where it connects to the Throttle Body was replaced a second time by GMC - The Throttle Body was cleaned
    3- Several months went by and the problem was occurring on a regular basic - the Throttle Body was replaced but failed again within a few days - GMC wanted to replace the cable AGAIN - I said NO and ordered a replacement cable online and repaired it with good solder joints and shrink tubing - this was a much better job than GMC did on the two previous repairs - I learned MIL Spec soldering years ago and have not lost my touch - But, I am sorry to say the problem did not go away
    4- The Throttle Body was cleaned again but the problem remained
    5- I remembered the wiring harness was repaired by GMC in TWO places originally so I wiggled the cable at the 2nd repair and REP would come and go as it moved
    6- I took the truck to GMC but they wouldn't even look at it until I could get the truck there while the REP was occurring - moving the cable at the dealer would not recreate REP
    7- When REP occurred I limped into the dealer - WARNING: Do NOT let the dealer turn the engine off to read the mileage - give them an approximate mileage
    8- I showed the dealer where I wiggled the wiring harness again - it still would not cause REP to go away - I went for a test drive in a new GMC while they troubleshot the problem
    9- During my test drive the service department called and said they were replacing the cable to the Throttle Body AGAIN because of the computer codes read which INFURIATED me - I told them to not touch it
    10- We returned to the service department and smoke must have been coming out of my ears
    11- I showed the actual service technician where I had seen the problem - the service manager didn't even tell him about it - while I was standing there he took the wrap off the cable where the original repair had been made and said "There's the problem, it was repaired using butt splices, and should have been soldered according to the service bulletin."
    12- He repaired it correctly and it's been working perfectly ever since.

  • I bought a 2007 Yukon Denali a month and a half ago and it has been a nightmare with this thing ever since! First off, 24 hrs after we bought it the chrome back passenger door handle broke off. A few days later the check engine light came on. Took it to local GM Dealer and they said it was throwing the EVAP CODE, (something to do with the exhaust), quoted me 500 dollars to fix it. A couple days later slowed down to pull into a parking spot and it just died out of the blue! Immediately put it in Neutral and it started right up and run fine after that...For A Week. We took the kids outta town the next weekend and it was fine the 100 miles to our destination but on the way home that evening we were sitting in traffic for about 30 mins waiting to get on the interstate and it started Stalling. It ran fine on the interstate for a few miles then outta nowhere the Stabilitrak and Check Engine Lights started flashing. The computer screen read 'Service Stabilitrak, Traction Control On and Reduce Engine Power'. It went to shaking violently and lost all power. This lasted for about 10 miles then stopped and went back to running fine till about 20 more miles down the road and started again but this time it didnt go away. Eventually it started backfiring real bad. So we 'Limped' it as close to home as we could then had it towed home from there. Needless to say, we have a very expensive yard ornament now. I've read about this exact problem on a thousand different forums with a bunch of different 'fixes'. Anybody have this problem recently? And how much did it cost to get it fixed?
  • Good morning bethleann,

    We're sorry to hear that the Yukon you recently purchased has been giving you these troubles already! If you were planning on working with a GM dealership and wanted for us to look into this further with you, please send us an email at with more details, including: your name and Edmunds username, phone and address, the last 8 of your VIN and current mileage, and the name of your involved dealership.

    Sarah, GM Customer Service
  • Good morning,

    I have just experienced the exact same problem as message #480. 07 Denali XL 74000 miles. While towing a small load with transmission in tow mode (3 motorcycles, small enclosed single axle trailer) total weight aprox 2800 lbs on the hitch. Arrived at my destination 122 miles, let truck sit with load not attached. Re attached load started with remote key and when I put key in truck and put in gear and flashing on the dash Stabilitrak On, Traction Control and Check Engine Engine at Reduced Power. I let truck idle while in gear for aprox 50 yards. Stopped put in gear turned truck off unweighted hitch disconnected the battery & reconnected the battery twice. Started truck with the key this time and it ran fine for aprox 50 miles then displayed the same syptoms again. Repeated the process & it ran fine again until I shut it off 100 miles later. Lights are on again and this time wont go out.
    How much should I expect to pay the worst case scenario? ? ?
Sign In or Register to comment.