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GMC Yukon Reduced Engine Power message



  • After 2 new Throttle bodies my cars are like champ again. Not even think in going to the "STEALERS" lots of BS and nothing fixed, the only thing that I need from them are the parts and even needing parts I could get much cheap from GM Parts Direct.

    Good luck folks.
  • I have been having this same problem. I have a 2003 Yukon Denali XL.. I have had it in the shop 4 times and its still not fixed. I am afraid to go any where in my vehicle and its scares me when it jumps into the"reduced engine power" "stability system disabled" mode. I have to pull out of traffic and sit on the side of the rode. To travel less than 30 miles I had to pull over seven times. I have read each of your statements and I really don't understand what actually fixes the problem...please somebody help.....
    Thank you for your time.
  • I have been having this same problem"reduced engine power" "stability system disabled". I have a 2003 Yukon Denali XL.. I have had it in the shop 4 times and its still not fixed. I am afraid to go any where in my vehicle and its scares me when it jumps into the"reduced engine power" "stability system disabled" mode. I have to pull out of traffic and sit on the side of the rode. To travel less than 30 miles I had to pull over seven times. I have read each of your statements and I really don't understand what actually fixes the problem...please somebody help.....
    Thank you for your time.
  • I want to make sure I am understanding correctly replacing "throttle body" fixed the "reduced engine power" "stability system disabled" issue ? I have had mine in the shop 4 times and it needs to go again...I don't have money to keep guessing what's wrong. I trust my mechanic totally..he is a very fair and good man... and has worked on GM cars for years. I can see the frustration in his face when he addresses "the codes" and they don't solve the problem.
    Thank you for any insight...
  • I had the same issues and had brought it to my mechanic and the Chevy dealer. They replaced everything from the gas pedal to the wiring harness and still same problem. I refused to give them more money and solved the issue myself. I looked over the the wiring harness that had been replaced by the Chevy dealer and found they did a lousy job splicing the wires together. I cut the wires back another few inches and spliced together and have been smooth sailing since. Hope this helps.
  • Hello My Fellow GMC Owners!

    I am posting my recent ordeal with my 2007 GMC Yukon, because I too am extremly frustrated with the incidents and mainly GM, and their poor products, and customer service. Over the last month, I had three seperate incidents whereby I was driving and the check engine light would appear, and within moments, the engine reduced power message flashes, and the vehicle loses power. Luckily, each time I was able to pull over to the side of the road/interstate and out of harms way.

    I took the vehicle to the same GM dealership each time. The first time, they reset codes and cleaned the throttle body. Two weeks later, the incident occurred again. Back to the dealer, and this time, a different set of codes (unsure which ones) and I rode off into the sunset. Only to return three weeks later, with the same issue. On this visit, the decision was made to replace the throttle body.

    Here is my issue - my 2007 GMC has on 77,000 miles and is covered under the 5yr/100,000 powertrain warranty. The throttle body assembly is a covered component under this warranty. In 2010, the warranty was altered by Gm and they no longer cover this part, amongest several others. But this is only for 2010 models and newer! Therefore, models 2009 and older ARE covered. I had to generally go to war with the GM Area District Specialist, about this issue. He wanted to say because they made the changes to the 2010 warranty (removing the throttle body assembly as a covered part), my 2007 vehicle was no longer covered. After a week of constant debating, and the investigaton by a different District Specialist, they covered the part and advised the confusion was their error.

    So, if you have a vehicle with the specified problem and it falls under warranty (within the designated mileage, less than 100k miles) FIGHT to make certain it is taken care of under your warranty. This part is $500+ to repair out of pocket, and you shouldn't have to pay it when it is covered.

    Hope this helps! In addition, I have filed this complaint with the National Highway Traffic Safety Administration (, and your complaints can help our problems be elevated to a recall status, and protect others and even safe a life. Go to their webite or call to file the complaint! There is strength in numbers! Also, please see the attached bulletin below. This way you can read it for yourself. Good luck!


    GM Service Operations
    **Urgent Message**
    DCS 412

    DATE: September 21, 2009

    TO: All US GM Dealers, Service Directors, Warranty Administrators and Parts Managers

    SUBJECT: Changes to the General Motors 100,000 Mile/5 Year Powertrain Warranty for 2010 Model Year Vehicles

    This message is to provide information regarding the a few changes to the GM Powertrain Warranty for 2010 model year vehicles. Previous model year vehicles are NOT affected by these changes.

    For model year 2010, General Motors is announcing a slight change in the components that are covered under the 100,000 mile/5 year limited warranty on all light duty cars and trucks. The Warranty and Owner Assistance Information booklets have already been updated with these changes in all New 2010 model GM vehicles.

    The following items have been eliminated from the Powertrain portion of the coverage for 2010, however, they will continue to be covered for the entire length of the Bumper to Bumper Limited Warranty for all GM vehicles. Select components may also be covered by Federal or State Emission coverage. Please refer to the Labor Time Guide and Policies and Procedures (P&P) manual for further details.

    1) The entire pressurized fuel system (in-tank fuel pump, lines, fuel rail, injectors and return line.
    2) The Engine/Powertrain Control Module (ECM/PCM) and module programming.
    3) The Transmission Control Module (TCM), Transfer Case Control Module and module programming.
    4) The Throttle Body Assembly.
    5) Clutch and Pressure Plate for Manual Transmission.
    6) Sealed Wheel Bearing Assemblies or Hub and Bearing Assemblies (axle shafts, seals and bearings that are part of
    complete axle housings are still covered).

    The following items have been added to the Powertrain portion of the coverage for 2010.
    1) Engine oiling system including the hoses, lines and cooler.
    2) Crankshaft Pulley.
    3) Clutch Master Cylinder.

    The GMVIS (GM Vehicle Inquiry System) and the new Global Warranty Management Investigate Vehicle History screen allows you to identify this new warranty by the abbreviated description under the Applicable Warranties section. The word warranty at the end of the description is abbreviated “WTY”. Previous 100,000 mile/5 Year Warranties have the entire word spelled out.

    See: for the full posting of this memo.
  • I work and a car lot and i had the same problem with 2 of my trucks , i fixed the problem with the first GMC truck changing the battery and the other one was the ground ,.
  • At least on my case, both cars had the TB with problems. The mechanic that I take my cars for electronic problems is MUCH MUCH more experienced than any other DEALER (per say) specialist and he has lots of years specific in electronic diagnostic trobleshooting, so he's basically like a very good neurological doctor that can answer lots of questions and find solutions where things don't look so logical. I had both cars fixed at the same day, but I want to make it clear that even my guy said other problems can cause the "reduced engine power". So on my case so far so good.
  • My mother-in-law is having the same issues with the 'reduced engine power' light. I'm very suprised that there has not been a recall on the faulty parts or even the entire vehicle itself by GMC. This problem can be very dangerous. The most recent incident left my mother-in-law and her 2 children suddenly stuck in the middle of a very busy freeway with no power. I guess once someone reports injury or death then GMC will take action.
  • My yukon Denali 2003 is back in the shop for the 6th time. I can't believe GMC doesn't care about its customers more. I was brought up to believe in America and her products but this is really making it difficult. Unless something is done soon. I know I will not ever recommend a GMC or purchase another one myself.
  • Dear GM Customer Service,
    My vehicle has approximately 160, 000 miles. The barrings have been replace the wires have been grounded, a new battery to make sure ample power is there...I will be going down the street, highway, interstate doesn't matter how fast or slow I go ... it will going along and without warning it powers down and gives me on the display REDUCED ENGINE POWER then it drops to around 10 miles per hour also right behind the display message REDUCED ENGINE POWER it gives the message Stability System Disabled. I can pull off the side of the road after much honking of the horn and stress..turn the key off and wait a few seconds crank it and go again..sometime it doesn't do it again other times in order to travel 20 or 25 miles I have to pull over 7 or 8 times.. do you have any idea how frustrating this is or for that matter how dangerous this can be? GMC please do the right thing...recall or at the very least get the information out to your mechanics how to repair the situation without people having to take the vehicle back again and again and again...
  • Yes Christina, you can tell us what is causing this problem?
    Thanks, Gary
  • keri5keri5 Posts: 1
    I have a 2007 Chevy Monte Carlo and have been dealing with a reduce engine power for the past month. This has cause me frustration as well danger when I drove my vehicle on the highway when I lost all my power.

    I never deal with the dealerships when I need work on my vehicle, I have a mechanic in town who doesn't rip me off. This time he not sure what's going on with my vehicle and doesn't want to want to start guessing.

    The other day I dropped my vehicle off at the dealership wereI purchased my car. when I started to explained what was wrong with my car he said to me you can write it down on this form and we will be in touch with you on Monday or Tuesday. Also, there will be a 90 dollar diagnosis charge. There was no customer interaction, and showing they wanted to work with me.
  • gmcustsvcgmcustsvc Posts: 4,251
    What I need you to do is send me and email with your complete contact information including a good number to reach you, VIN, current mileage, and involved dealer. Please include the post I am responding to in your email.
    Christina GM Customer Service
  • gmcustsvcgmcustsvc Posts: 4,251
    I apologize for your experience. Have you taken the vehicle in to your local GM dealer to be diagnosed? If not i would definitely recommend doing so. Please keep me updated on your situation.
    GM Customer Service
  • I had the same problem as everyone else with the reduced engine power on my 2007 Yukon Denali. I broke down on Jan. 29, 2011 and again on Jan 31, 2011 both times on major highways in dangerous spots. The problem is GM knows about the faulty fuel throttles and they are not willing to do a recall. The fuel throttles are on national back order and I had my car in the shop from Jan. 29 (with the exception of driving it 106 miles before breaking down again) until today Feb 16th. when they finally located the part and fixed it. I've had nothing but problems with GM customer service. I have been in constant contact with GM in Detroit, supposedly at the executive level. They do not care about customers, in all of my issues resulting from my fuel throttle (I was towed twice for this problem once from GM Roadside and once from AAA one of the tow trucks damaged the front of my vehicle, I don't know which one and neither will take resposibility for it, so GM told me "sorry, I feel your pain but its out of our hands"). So therefore I have dents and scratches that need to be repaired at my expense! I have no respect what so ever for GM, I was a loyal customer up to this point, and I am done. They are endangering peoples lives and do not care. I wonder if the executives would be so careless if this were happening to their loved ones. Something tells me not. For all of my troubles I was offered a customer loyalty certificate for the purchase of a new GM....really?
  • breze022breze022 Posts: 8
    After 6months of searching the web I found this site. It has been very help full the only problem I'm having is my 2003 Yukon denali has the same problem as other with the reduce engine power...the only difference is that when I start it up and drive to the store when its time to go it won't start back up after replacing the throttle body,starter,tac module map sensor crank sensor I can't figure it out I've check for loose or broken wire everything is fine can you help me
  • breze022breze022 Posts: 8
    I have the same issues the only thing is the reduce engine power comes on when I drive to work or the store then turn off the truck it won't turn back on and then my display will say reduce engine power I have to wait about 30 minutes then the truck turns back on like everything was normal
  • I have been frustrated by this reduced engine power enigma. When it first started occuring about 6 months ago I took it to autozone for a free diagnostic. The code came back as throttle position sensor, TAC, or TPS. I was convinced for whatever reason that it was the TAC, so I went to the Chevrolet dealer parts counter and requested one after explaining what was going on to the clerk. He advised me that I should have a technition look at it so I scheduled an appointment. Of coarse you can't speak with a knowledgable mechanic at the dealership so I get a call from the customer service rep and she tells me I need a new throtle body and throttle body harness which they could install for only about $900. I told her I would fix that myself and forego the $1000/hr labor charge that they get. Paid $90 diagnostic fee for the same info I got at Autozone for free. I purchased the overpriced harness from GM (as that is the only place to get one) for $140 and a new throttle body from Autozone (for $158 vs. $300 at Chev) whent home and replced the parts in about 20 min. Guess what, same problem so I go back to my thinking that it is the TAC. So I buy a TAC from Chevrolet as tho only supplier for $300 still the same problem. I call the customer service rep at Chevrolet dealership and she tells me that I must have the computer reprogramed after changing these parts. I set up an appointment and pay $100 dollars only this time I strategically wait for the mechanic to come driving up and corner him. He tells me that it could have been several things but it is deffinately fixed now and all codes are cleared. 30 minutes later the same problem. I changed the throttle position sensor as well as the mass air sensor but still have the same problem. I have wiggled the harness on the throttle body as somebody suggested with no changes. A friend of mine has the same truck and is having the same problem. I believe this is common and GM doesnt want to take care of it. After 40 years of GM loyalty I am done buying them but I am stuck with 2 now and don't know what to do. From what I gather no one else does. btw this truck has 180000 miles and runs well except for this
  • turk744turk744 Posts: 1
    Dear GM Customer Service,
    I have been a GM owner since 1969. I religiously buy your products because I believe in AMERICAN MADE PRODUCTS. I have a 2003 Silverado Crew Cab 4x4 Quadrasteer SLT, that has 161,000 miles and I am having the same problem that everyone else seemingly has. I am currently afraid to drive it, because I have to get onto the interstate to travel and I've almost lost my life several times in the past month because my truck just quits or shuts down when I am driving. I took it to the Local Dealership and they said they could fix it for about $190.00, so I let them. When I went to pick it up I looked at the bill and the actual parts were $4.29, the rest of the cost incurred was labor. Before I got home, (12 miles), it had broke down twice. I called the service manager and he said that all they had to do was clean the throttle body and I would have to be patient and keep adding injector cleaner to it every week and it will take some time to clean the system. Well I think that after $500.00 in fuel and additive I am ready to throw in the towel and park it for good. What a shame to have a truck that still looks brand new and can't be driven for fear of losing your life. In my opinion, your vehicles with this problem are no longer safe to drive and I don't think that your "Mr. Good Wrenches" have a clue on how to remedy these current issues. Not knowing how to fix your own products surely will not help you sell vehicles. In short, I'd just like to ask that you please help the people that have kept your company in buisness for Centuries.
  • I am having the same problems with my 2007 Yukon XL Denali, after having my transmission replaced last December, here we go again with something else. I am so frustrated with GM Customer Service and lack of concern for their customers this reduced engine power is very dangerous. Having this power failure on the interstate in the middle of nowhere is a big problem.
  • gmcustsvcgmcustsvc Posts: 4,251
    Can you please email me with your VIN and case number?
    GM Customer Service
  • gmcustsvcgmcustsvc Posts: 4,251
    Have you had the chance to have it seen by a dealer? Will you email me your VIN and situation?
    GM Customer Service
  • bunchz71
    I have a 2007 GMC 1500 series w/160000+ miles. We just acquire the reduced engine power msg. Tried to get your picture and could not get into site. Do you have a different address for this picture, I noticed later on you said your site had been down for awhile. I could use the picture to find the wires in my truckAppreciate any help you can give on this matter. thnx smedsleas
  • I have a 2003 Chevy Z71 Tahoe ... same problem "Reduced Engine Power" it's random. The only problem I do face right now is my catalytic converters, which I'm about to replace. Could be why I'm getting this message?
  • Hello, I have had this same problem. My stabilitrak and traction control lights went off followed by the dimished engine power. Took it to the dealer and they said that it needed a throttle body and throttle body connector, BUT that the part was on national backorder...could be weeks or a month. (that was 02/2011).

    Finally got it replaced on April 4th..cost $500. My Yukon XL has 124K miles on it, bought it new and I asked GM to pay for the part....FLAT out denied! My warranty has expired, so they don't care....even though it is obviously a problem part. Then GM Customer service told me to save my reciepts if I wanted to be reimbursed for the cost if the part was recalled later! They basically don't care.

    In addition to the problem with the throttle body, my 2007 GMC Yukon XL has all the other problems that GM won't acknowledge...Excessive oil consumption and it has to have a new battery EVERY year!

    Won't be buying GM next time....
  • I also have a 2003 Yukon that drops in to Reduce Engine Power mode. The Throttle Body has been replace the ground at th back of the cylinder head on the passenger side has been reworked a new pig tail harness to the trottle body has been replaced and I still have the problem. In my case the condition has been evolving at first it was seldom and random it seam to be when you held the accelerator pedel steady at approx 65miles an hour. It now happens 14 times in 14 miles Saturday morning then I drove 100 mile on sunday afternoon without a problem the only difference was the outside air temperature. I too am looking for a solution to what appears to be a common problem. :confuse:
  • datsamoredatsamore Posts: 10
    Your; need new battery every year problem is most probably caused by the ground strap from the battery to engine block is loose. I went thru too many before I figured that out.
    Now if I could figure out why it keeps going into limp mode!!!!!
  • I will check that out! Thank You.
  • I replaced the Battery and Alternator still having the same problem. P0120, P1516 and P2135
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