GMC Yukon Reduced Engine Power message

bonddogbonddog Member Posts: 6
edited June 2015 in GMC
I purchased my 2006 Yukon last September 2005. I now have 24,000 miles on it. Over the last month I have had it into the dealer three times for the same problem. The problem is that while driving the vehicle it will suddenly lose almost all power. The Information Center will display the messages: "Stability Control Disabled", "Engine Power Reduced". And the vehicle will not go over 20 mph on a level surface and bearly 3 mph up a moderately steep hill. Each time I have had it into the dealer for repair they have beeen stumped by what the cause of the problem is. They said that GM/GMC told them that "GM is aware of the problem but does not have a fix for it at this time". How can a manufacturer sell a vehicle that has a defect and not have a fix for it? When the power goes out in a busy intersection or on a highway this is a major safety issue. Has anyone else experienced this problem.
Thanks, Steve

See Also: Reduced Engine Power Message Displayed on GM Vehicles


  • rshtrsht Member Posts: 277
    From your description, it sounded to me that there May be a couple of areas you want to check; but before you do anything, I suggest you barrow a good battery charger to fully charge your battery first. Upon fully charged your battery, try to start the engine and then turn it off and back on to see if your clock still resets to 12:00? If it does, you may have a problem with wiring/connection to the ignition switch... As far as the battery charge, how old is the battery? Have you checked the battery fluid/acid level in each cell (be careful, not to smoke or have spark around when checking)? Its possible that you may have a bad alternator like bunchz71 said in the previous post. You can do a primitive check with a volt meter from the battery terminals with ignition off (~12.6VDC) and with the engine running (~14VDC); but the best is use a proper battery/alternator tester, perhaps your local AutoZone, Advanced Auto or similar can help and ID if its the battery or the alternator is due for a replacement.
  • stephc1stephc1 Member Posts: 6
    Hi Steve...I just had the same problem yesterday...and the problem went away just as fast as it came on. I researched it online and saw that it's something that comes and I called the dealership this morning to see what they had to say and the service guy told me he was very familiar with the problem and it seems to occur if you don't turn the vehicle off when getting gas or when the gas cap is not on tight enough. When I got that "reduced engine power" thing I got scared and went home right away...turned the vehicle off, waited a few, started it back up and it's fine now. Very strange. Good luck and if you find anything out about this problem please post it. I love my Yukon...but I sure wasn't too happy with it yesterday! Stephanie
  • guestguest Member Posts: 770
    Update...the day after my last post I was driving and my Yukon just shut down completely. I have looked on the internet and have found A LOT of people with the same complaint. I called GMC and filed a complaint...told them that this should be a recall since it's such a serious saftey issue. Didn't get much sympathy from them and am very upset at this point. I'm making payments on a vehicle that isn't safe to drive. It's sitting in the shop now...noone seems to be able to agree on how to fix it. If anyone has any further info on fixing this problem PLEEEEAASE let me know! Thanks! Stephanie :cry:
  • bonddogbonddog Member Posts: 6
    Hi Stephanie, sorry to hear you have this problem. When in your last post you mentioned that the dealer told you that it was probably a loose gas cap or not shutting off the engine while filling up I knew you'd be back. Those were very bogus excuses. I had the problem again last week and they replaced the Throtle-body on my engine (which is what they fixed the time before that). So far the Yukon had been running fine. But it's only been a week. I got GM involved this last time. They setup a file and promised to call me back and follow up. They never did. We need to all stay in-touch in case we have to force a recall with a class action suit. Keep me posted. Steve, in New York. :lemon:
  • stephc1stephc1 Member Posts: 6
    Things have gone from bad to worse with my 2003 Yukon XL.
    You need to be CAREFUL!! Mine was fine for a week and then went nuts again with all the kids in the car. Mine was in the shop for a week...ran fine for a week and then died again. Seems like whenever they mess with the wires it behaves for a little while. Dealership is NO help...GM is NO help...I have no idea where to turn at this point. I have a beautiful vehicle...sitting in the driveway, can't use it. GM and the dealership didn't seem to give a damn that this is a MAJOR safety fact when I called the dealership this morning I was so upset I was crying...the manager said that he "didn't like the way I was speaking to him" and said there was nothing he could do for me. I wasn't even letting him have it! I am SO fed up and confused. I even went to a FORD dealership today to see what they had that actually ran and stayed running...only found one SUV I liked enough to test drive...but all I did was bring it home, park it next to my Yukon, and make fun of it...I hated it...I just want my Yukon. If you find any further info on this please let me know. There are several TSBs regarding this issue but GM didn't seem overly impressed with that either. Hopefully someone will be able to solve this problem. Stephanie :lemon:
  • brycemanbryceman Member Posts: 1
    Hello from a new member of the Club. We just purchased an 03 Yukon one month ago. Yesterday my wife called and said the sound on the stereo had stopped working. A few hours later she called and said that it would not start. This morning I tried a jump start. It did start, but then I could not rev the engine over 1000 RPMs. I tried to take it for a spin, but couldn't get it over 5 mph. Lo and behold there was the "Reduced Engine Power" message you've all been talking about. This is a real concern. If that happened on the freeway we'd be in serious trouble. It sounds like taking it in to a shop may be futile though. Keep me in the loop on what's happening with you're rspective vehicles. GM does need to deal with this.
  • stephc1stephc1 Member Posts: 6
    Don't pay huge money for diagnostics...please read!!!! I finally found someone that fixed my YXL and fixed it right...The problem is the ground wires. My mechanic tightened one that he found loose and the other one the clamp was messed up so the ground wire was flopping around and not making a good connection. When he touched the ground wire he could hear the fuel pump going on and off and other things making noises. It was a $3 dollar clamp that fixed it...too bad I spent almost $2000 on diagnostics with the dealership that was trying to tell me I had a bad transfer case module as well as a bunch of other BS and another mechanic before I brought it to this guy. Make sure your mechanic checks all the grounds (I didn't know that there's more than one) and tightens them as well as making sure the clamps are in good condition. My clamp was broken causing a bad connection.'s a $3 part that caused this hellified problem! I'm just glad to have my vehicle back in good running thanks to the dealership or GMC! :)
  • stephc1stephc1 Member Posts: 6
    Just wanted to let you all know that the last repair I posted about seems to have really worked. I was nervous for a while...waiting for my vehicle to die again but so far so good. (I'm probably going to jinx myself by writing
  • bctbct Member Posts: 8
    I was wondering if anyone knows of a way to convert the rear drum brakes on a 1999 Yukon Denali to disc. Any help would be great, stopping a 3 ton truck is not fun with those stock brakes. That may be why they changed the rears to disc on the 01.
  • beaudoinbeaudoin Member Posts: 3

    please check this site and you will find a complete conversion kit available to you ...hgb
  • jtallenjtallen Member Posts: 2
    Hi there. I'm glad I found your postings. I just bought a 2001 Yukon Denali and it stalled on me the very day I was driving it home from the dealership. It started back up so I didn't think much about it. The next day it died and I had a hard time doing anything. It would sputter and die over and over. If I did get it started it would die if I got it up to 10 mph our so. Can you tell me where these ground wires are that you were talking about? Are they grounds for the fuel pump? are they located inside the tank? Any info you can give would be greatly appreciated. I am so sick that I spent that kind of money and it breaks down the same day I buy it.
  • bctbct Member Posts: 8
    The rear end in my 1999 Yukon Denali just blew up. Haven't taken it apart yet but something actually came through the cover from the inside out. I was wondering if anyone knew if I could get a rear end from a junk yard with disc brakes on it that would just bolt in place. I figure that if I have to change the rear end I might as well upgrade it to discs instead of those drums, plus the tow truck driver managed to kill the wheel cylinder on the passenger side anyway. Any help would be great, thank you. :sick:
  • hershbbkhershbbk Member Posts: 1
    Hello everyone,
    I also have a 2003 Yukon. I have had the engine light on the last few weeks, have had it diagnosed, One place stated it was Fuel Pump and Fuel Filter, another o2 Sensor and another Mass Air Flow Sensor. I replace Fuel Filter. Light went away for a while. Its back on I had it diagnosed after unpluging the MAF Sensor and it gave the same codes as a bad MAF Sensor. This morning I went to start my car, it started then stopped, and the code that you all are talking about speared for the first time. Reduced Engine Power, and it will not start. Can anyone tell me what ground wires were found bad, or if anyone has a fix to get the vehicle started?
  • fundadfundad Member Posts: 27
    That doesnt surprise me a bit. Most "hard to find" electrical problems are bad grounds. A friend of mine works at a Chevy shop and told me that they are told to replace parts before looking for bad grounds. He said he was actually told to do this for "repeat work". Anytime you take a vehicle in to any shop for repair work you get ripped off. Do you really believe those hourly rates to do work. Had an intake crack and was told $1400 to replace it. I bought a new intake off the internet for $199.00 (dealer wanted $799.00) and it only took 90 minutes from first opening the hood till I had it running with the new one on. The dealer told me 7.5hrs labor @ 80.00/hr to do it plus parts. What a crock.
  • beaudoinbeaudoin Member Posts: 3
    Hi I spoke to Steph mechanic by phone the problems you are experiencing are all pointing to a low fuel pressure, the computer looks at all perimeters and makes a call via codes,the reduce power light is st when the abs sees a wheel spin, or thinks its sees a wheel spin and disables the throttle from being active hence you cannot move forward any faster, disabling the 4x4 to two wheel drive should allow the vehicle to move forward most causes of this particular code is set by rust build up under the front wheel speed sensors. Bonddog, I would suggest that a fuel pressure test be performed using a know good fuel pressure gauge should have 60psi minimum (critical) with the key being cycled on, pump is purchased as a complete module assembly very expensive and fuel filter should be performed when replacing the pump. In summary the lean codes that were set were probably set due to low fuel volume, If you turn the light off and changed the filter and got a few extra miles you can bet on a pump, sorry for the news....hank "Reduce power is altogether another bag of tricks to worry about.
  • clintdownsclintdowns Member Posts: 2
    :mad: Hello to all. I am new at this, this is the first time that I have looked at this site. I just took my truck into the shop today for the second time in three weeks for the reduced engine power coming on. When it happens, it runs like [non-permissible content removed]. the first time I tool it is they sais that the machine told them to replace the throttle positioning sensor, well guess what, it told them the same thing today. One more time and do I have what they consider a lemon. Any feedback, what do I do. :mad: :mad: :mad:
  • clintdownsclintdowns Member Posts: 2
    By the way I have a 2006 Chevy crew cab LT Silverado :lemon: :lemon: :lemon: :lemon: :lemon:
  • bulldog15bulldog15 Member Posts: 1
    I have a 2006 Grand Prix with 10,000 miles. Two months ago I started getting "service traction control"/"reduced engine power" messages and couldn't get the car to go over 15mph. Took it into a Pontiac dealer and they replaced the throttle body. Two days later, same thing happened and the dealer replaced the accelerator sensor. Three days later, back in the shop where they replaced the powertrain computer module. Two days later, back in where it stayed for five weeks while they tried to figure out what to do. Finally, GM tech pinpointed the problem and the dealer replaced the fuse box. I've had it for two weeks now without further problems however, I'm keeping my fingers crossed.
  • bonddogbonddog Member Posts: 6
    I started this thread last August 2006. Since they replaced my Throttlebody I have not had the "Reduced Engine Power" problem. It's been 9 months now and trouble free. It turned out it was the throttlebody all along but the GMC mechanics did a lousy job of fixing it the first few times in that they didn't notice that they had crimpped some wire when they installed it causing it to malfunction. Believe it or not some newer Corvettes have experienced this problem too.
  • bunchz71bunchz71 Member Posts: 10
    Hello all,

    I just wanted to share with everyone with the problem that I had with my 2003 1500HD Crew Cab with 6.0 Liter. My truck would go into reduced engine power off and on. Sometimes one a week, sometimes 5 times on a 20 mile trip. My problem was a broken wire on the plug in going in to the throttle body. In the picture is the plug in that had caused me all of my pain and grief....... My problem was very intermittent and was hard to diagnose. I started vehicle and with all codes clear. I wiggled the wiring harness in the picture and vehicle spit and sputtered, throwing it into reduced engine power mode, and then smoothed out to a smooth idle. I disconnected the plug and pulled wires out of plug end and found a broken wire. Mine was a brown wire with white stripe. BUT, what was interesting, was that this vehicle had apparently had the smae problem with previous owner, becuz there was another wire (yellow wire) right beside the one that I found broken already soldered up and taped from where it had apparently happened before. This was my problem and not my truck is running great, and actually even idles better that before. Hope this helps with any problems that anyone else is having. I know this problem can be very irritating.
  • heymiltonheymilton Member Posts: 3
    I just wanted to let you know that I had the exact same problem in my 2001 yukon xl. Reduced engine power happened about 6 times in a couple of months. I was taking it to the dealer for a recall and on the way there it happened again.
    Frustrated I told them to look at it and fiqure it out. I searched out the best mechanic and he was knowledgeable and worked on it. Said it was a bad ground , charged me 80 bucks and I was on my way. Problem was 5 miles down the road i got reduced engine power again. Turned around and took it back to them. long story short they had it for a week and said they could not fiqure it out . they wanted to throw parts at it starting with a 400 dollar one. I read your thread and told them to check out the wires at the throttle body, they told me they already did, and refused to look at them again. I went and got the truck and decided to go with your suggestion , took apart the cannon plug and found NO broken wires. Decided to replaced the metal contact pins themselves. cut them off and went to a different dealership to parts and look thru a ton of contact until i found the exact ones. replaced them and soldered them just in case and I HAVENT HAD THE PROBLEM SINCE. Im guessing it was just a bad contact pin, just enough to trip the computer.

    Thanks for the info , your time writing your thread probably saved me hundreds of dollars.

    I have never taken a vehicle in my entire life to a dealership for repair , they are thiefs. Look and ask around for a local repair shop with a good reputation. you will save alot of money, and I am NOT talking about a Firestone or something like that, more of a mom and pa shop

    BTW,,,,,,,,,,,,I am a american airlines aircraft mechanic for the last 20 years
  • bunchz71bunchz71 Member Posts: 10
    Cool, Glad I could help. I had actually already started replacing stuff on my truck. I replaced the Foot pedal, that has the 2 TPS built in to it. It was $120, and it still did not fix the problem. I dont understand why Chevy didnt just keep the throttle cables lol. I never heard of these problems when the throttle was cable-less. haha. I ended up just replacing the entire pigtail end to fix my truck. The pigtail end and about 18" of wire was $140 @ the chevy dealership. I about freaked when he told me how much it was. But I figured, this will fix my truck and I wont have to worry about this annoying problem. If you do want to replace yours as I did, here is the part number.

    AC Delco

    ACD# PT1572
    GM# 88986255

    Hope this helps.
  • afwafw Member Posts: 2
    I have continually had the same messages displayed on my 2004 Yukon XL. (Reduced Engine Power/Stability Control Disabled/Service 4 Wheel Drive along with the check engine light.) Yesterday for the first time it would not go over about 20 mph. First time it happened the dealer said it was the battery. It was okay for a few weeks, lights on again, but went out the following day. Then it happened a third time, took it to another shop and now is back in the shop again. I will be getting him the information everyone has posted. Have those who thought they had the problem resolved still doing okay, no more lights & messages? By what I have been reading, many people are having the same problems. How do I report this problem to GM? Would a letter writing campaign to GM help this matter?
    Of course, this problem started about 4000 miles after warranty expired.
  • stephc1stephc1 Member Posts: 6
    Hi, After the repairs I mentioned about a year ago (bad ground) I have never had anymore problems. *knock on wood*
    When I contacted GM they really just did not care. This issue shows up in the TSBs but what it comes down to is this: Until it kills someone, they won't do anything. I'd really like to know if this has been the cause of any serious accidents. If GM knows, they aren't talking.
    Best of luck to you. I know how frustrating this problem is and I don't wish it on anyone. :)
  • bunchz71bunchz71 Member Posts: 10
    Since I have replaced the plugin where my broken wire was, I have not had ANY problems. It was obviously my problem. My recommendation to anyone that has this problem very intermittently, is to start the vehicle while it is not in Reduced Engine Power Mode and have someone sit in the vehicle, while you wiggle all the wiring, plugs etc on the throttle body. This is the way I solved my problem. The plug in that i had to replace was not cheap, but its worth it to know that it is not going to go into reduced engine mode while a semi is on my [non-permissible content removed] on the interstate.
  • siemsensiemsen Member Posts: 1
    I want to thank everyone for the fantastic information. I have a 2001 Yukon and have been experiencing reduced power intermittenly on a daily basis. It only happens at startup. I shut it off, wait a few seconds, start it back up and then give it a good rev. 8 out of 10 times that does it. The other two takes another cycle. It runs great until I shut it off again. The idiot light comes on occasionally as well. If I run it pretty hard, it usually shuts off. So far my mechanic has replaced the catalytic converter, computer, and performed a fuel system flush. Luckily it is a "mom and pop" establishment and they have not charged me for the computer, fuel flush, or any of the time they have taken to diagnose it. I'm sure they feel that charging me for a cat which did not correct the problem was enough. I'm going back armed with the information you all have provided on the loose ground wire diagnosis. Hopefully that will do it. I will let you know.
  • azchevfanazchevfan Member Posts: 1
    I have a 2003 Silverado 2500 HD with a 6.0 liter engine. I recognize that I have a different machine, but I would think that there are similar engine components between the vehicles. I have been experienceing Reduced Engine Power message several times over the past 4 days. Local parts store diagnostic check said Throttle Position Sensor is bad. Sensor is not available at parts stores... only through dealership. Parts dept at dealership said TPS only comes as a complete package with a new Throttle Body Assembly. I purchased it and installed it only to have Reduced Engine Power message displayed again.

    I got truck home (at 15 MPH!) and started to examine wiring harness that plugs into the TPS. On my truck, the yellow wire was worn through and is shorting out. A simple wiring connector was the solution, rather than a $260 part. I encourage anyone to check wiring first.
  • bunchz71bunchz71 Member Posts: 10
    looks like you had the exact same problem as I did. It was even the yellow wire that was broke first. The yellow wire was broken with previous owner, this time with me, it was the wire beside it. I dont fully understand the reason for the breaking of wires there. The only thing that I can figure is that its right by the oil filler cap. Maybe it just gets bumped a lot while adding oil etc. Was your plugin like $120??
  • heymiltonheymilton Member Posts: 3
    hey bunchz71

    I just had the problem again!!!@! unbelievebly fustrating.
    are you saying that you replace this connector ACD# PT1572 and the wiring to fix the problem???? It was not the brown or yellow wire on the other side??

    I am ready to dump this thing.

    Btw did the wiring come with this connector or is this the price for just the connector??

  • bunchz71bunchz71 Member Posts: 10

    This is what I replaced. Click on the link below and see the plug-in. The connector comes with about 15" or so of "ALL WHITE WIRES". You need to replace one at a time so you do no get them crossed. It comes with 8 wire conectors also. I am not saying that your problem was the same as mine, but its possible. The main reason I went ahead and changed out the whole plug was because the wire was broke off about 1-1/16 from where the wire went into the connector and it made it hard to get a good solder job on the broken wire. I would recommed again wiggling wires with the engine running and have someone sit in the vehicle and let you know when it goes into Reduced Engine Mode. Its best to do it this was that way you know which wires you moved to create the error. Let me know if you need more help. I ll help if I can.
  • a1coblera1cobler Member Posts: 1
    Just wanted to alert everyone to another thing to check besides the Idle Control Wires and contacts. My 2003 Yukon XL had quit several times too by loosing power right in the middle of 70 mph on the highway. Received the Reduced Engine Power message on the last time it quit. While looking for a dealer to take my truck to I found this forum, which gave me a clue for my mechanic to look at. Here's the deal. In addition to replacing your Idle Control Body you can also have your mechanic take a loose the idle control body and check to see if it is clogged up. My idle control wires and contacts were fine. However the control body itself was extremely gummed up over 4 yrs of wear. My mechanic took it apart and used some carbuerator cleaner to thoroughly clean it out. Put everything back together and I have been good since. Cost me a few dollars for an hour worth of his time.
  • beaudoinbeaudoin Member Posts: 3
    Hey Bonddog,I dont want to burst your bubble on this but being a tech, and being very familiar with these issues,I just want to say that an Idle control valve does not have the capabilities of making the reduce power message come on. It is strictly for an idle control of the engine,the reduced power light and I have worked on this problem several times is usually caused by rust build up under the front abs sensors....I suspect that you will see your problem re-occur. hank
  • heymiltonheymilton Member Posts: 3
    Alright here is my latest. After this thing died and I could not get it going again. It was stuck in reduced enging power I finally had to make some drastic moves.
    The dealership wanted to replace the tac module on the firewall. But after I thought I had fixed it when I replaced the brown and yellow wire ends that connected to the trottle body and had 2 months of success I fiqured it had to have something to do with that. I ended up replacing the throttle body. The cheapskate in me found one in a junkyard on a totaled out yukon. It cost me 175 shipped to the door. Replaced it in about 20 minutes, and it fired right up. Runs like a champ.

    I am hoping this solves the problem and not just another teaser for a couple of months.
  • bunchz71bunchz71 Member Posts: 10
    Did you disconnect the battery for any reason during the swap-out ? If so this may have cleared out the code and started back up with no problems after the code was cleared. Hopefully you have fixed your prob. I still have not had any trouble with mine since i replaced the harness. Sounds like there is about 50 things that can make the Reduced Engine Power. lol
  • twidget2twidget2 Member Posts: 1

    My wife called on her way home and had the "REDUCED ENGINE POWER" message and the check engine light was on, 2003 GMC Sierra 1500, she did not think she would make it home, just a few blocks away. I checked the net and found this post and started checking at the battery and almost right away found that the negitive battery lead was not tight where it connects to the block, it was not arcing loose, just not snug, a 1/2" wrench to thighten the bolt and the engine idle returned to normal, the message and check engine light is off and it drives normal. Thanks for the help!!!
  • 07classic107classic1 Member Posts: 1
    I have an 07 1500 Sierra Classic with the 4.8 that just started having this problem. The first time was just before thanksgiving but after shutting it down it fired up and ran right so I just pulled the codes and they read that the TPS was "out of range". The check engine light turned off after messing with a few things: gas cap + intake. The thing is the problem just resurfaced again. I've got an appointment with the dealer as its still under warranty. From the sounds of things they are going to jerry rig a fix so can anyone provide any info that might help save me from constant trips to the dealer? :(
  • danny57danny57 Member Posts: 1
    it seems that everyone is talking about yukons. my son has a 2000 pontiac firebird with a 3.8 liter v6 engine. he has had the car for 16 months. he had problems with the engine so i bought another 3.8 v6 and now we are seeing the "reduced engine power" light come on. what gives? :confuse:
  • chipjumperchipjumper Member Posts: 2
    guys, after sifting through many posts and many different forums (like i have come to this conclusion:

    -Replace wire harness to throttle body (get the AC Delco OEM harness) probably

    This is from GM:

    The PCM detects that the commanded and actual throttle positions are not within a calibrated range of each other.
    The above condition is met for less than 1 second.

    Step 1. Tighten ground G103 located next to the right cylinder head (passenger side) just below the head and mounted into the block. The ground uses a 13 mm bolt head mounted vertically to the engine block just above the bell housing. G104 located behind the left cylinder head has also been found to cause this concern.

    Inspect throttle body torque. If the throttle body is improperly torqued to the intake manifold, remove throttle body and retorque the throttle body mounting nuts per SI in a two step process: 45 lb. / inches. on the 1st pass, and then 89 lb. / inches on the final pass.

    Verify all electrical connections especially right at the TAC module. There have been reports of the plastic retaining tab in the connector missing causing poor contact especially on rough roads

    Road test vehicle to determine if code re-sets/condition re-occurs. If not return it to customer.

    Step 2. If condition is not corrected using above procedure, or re-occurs, replace throttle body assembly.
  • chipjumperchipjumper Member Posts: 2
    In regards to the person with the 2000 Firebird ---

    I didn't know that car came with a Driver Information Center (DIC). Are you sure you're just getting a "Service Engine Soon" light or can you actually read, "Reduced Engine Power"?

    Those cars didn't use electronic throttles, at least I didn't think so.
  • problems2problems2 Member Posts: 3
    I have a 2003 Yukon XL Denali the Traction Control Light comes on the the Message Reduced Power comes on the it stalls and i can stop and restart it will run fine the rest of the day. Is there any new suggestions is it still ok to drive or need a immediate fix. This has just started since it has got cold and i nedd to put brakes on the rear could this be part of problem
  • bmcgbmcg Member Posts: 1
    Exact same problem just started for me for me...On startup, Traction Control Light comes on and the message Reduced Engine Power comes on. Engine is limited to 2000rpm. The 1st time this happened I shut the truck off, turned it back on, and it's fine. Other time I tried 3 starts with no luck, an hour later...I tried it again, and it's fine. Vehicle is an '03 Escalade. Any input would be appreciated, Thanks
  • problems2problems2 Member Posts: 3
    Well i have finally solved my problem we replaced the throttle body and the wiring harness and took all grounds loose sanded them the tightened them back. I got this from a message a fellow left on this site and it worked for me not had this problem for two weeks and i was having it daily.

    Thanks to all
  • momtofourmomtofour Member Posts: 2
    I cannot thank you enough for taking the time to post all of this information; I especially appreciate the photobucket picture, so I could locate what everyone was talking about. I went outside immediately, gently wiggled the wiring harness, restarted my 2003 Chevy Suburban... the REDUCED ENGINE POWER message was GONE... okay the engine light icon is still on, but I can drive my car now to the parts store... and thank you also for providing the part info and numbers and pictures... this has saved me a bunch of additional time...

    I thought we were going to be involved in a horrible accident today on the highway... YES, this happened on the highway and we had an 18-wheeler baring down on us with no where to pull off... I did have the forethought to put on my hazards, and most people were able to change lanes and pass us... but the 18-wheeler could not move over, and for some reason was refusing to slow down at a more reasonable speed... he was inches from my bumper before he finally changed lanes... I had 3 of my 4 children with me, all under the age of 5 in carseats... I was so scared...

    I cannot believe GM has not recalled or addressed this problem proactively... They will be hearing from me via certified letter...

    So thank you EVERYONE, but most especially, you... you covered all the bases for us... and lastly, I'm sure you saved us a bundle of money, something we cannot afford to be frivolous with these days...

    Laura (mom2four)
  • moe1954moe1954 Member Posts: 1
    I have a 2004 Yukon. My engine light has come on about 4 times sense I bought the thing. I keep taking it back to the dealer and they run dynostic on it and say that the fuel cap is not put on right. The last time I went there they put a new cap on it but the new cap goes on to easy and it dosn't seal good. It dosn't have the same seal in it the last cap I had, and now the light is back on. I guess I will put it in the repair shop if you cannot help me with this. I don't know if I should keep buying fuel caps or is there some wiring somewhere I can check. I don't know where to locate this. Thank you.
  • rshtrsht Member Posts: 277
    Not sure if you still have the old fuel cap? Some times the pressure relief valve inside the cap may be partially stuck, use a paper clip to gently push (through the little pin hole in the center of the cap) on valve to make sure it moves smoothly; as far as the cap seal (if you still have the old one), I would clean the seal and its contact surface on the filler opening. If all failed, personally, I would then hook-up an ODB-II scanner (your local AutoZone store can do it for free if you don't have a scanner) to see what is/are the trouble code(s) that associated with the Check Engine light... If the problem is with the fuel cap, the Check Engine light should go off fairly soon after the cap is on tight (~5-clicks...).

    Just for reference, one time I left the cap off, my Check Engine light came on before I was even out of the gas station parking lot. After I put the cap back on, less than a mile, the Check Engine light went off by itself...
  • flex4flex4 Member Posts: 1
    i have yukon XL 2001 model some time when i drive a car showing message REDUCED ENGINE POWER so you can help me on this :confuse:
  • rshtrsht Member Posts: 277
    Have you had the chance to read Message #22 from "bunchz71" on this topic of discussion? He/she posted a link to a picture on where the bad connection was that caused the "Reduced Engine Power" message. Your Yukon is a couple of years older, so the position of the wires/connector may be in a different location.. Hope you locate the trouble maker easily with the information from this forum.
  • ea4presidentea4president Member Posts: 1
    This morning I went shopping, came home everything was fiine, I tried to go back out a couple hours later, and I got a "ENG REDUCED POWER" message. I tried to turn it off and restart the car maybe that would fix it... nope. The car still ran so I tried to go around the corner, the first time i stopped at a stop sign I had to restart the car. Then the message didn't appear anymore. I continued to a gas station, got the same message when i got back in the car, and called for service. If anyone has any clue how this happens or how to fix it please let me know. :confuse:
  • drew36drew36 Member Posts: 1
    I've had a 2005 Express 3500 for awhile now and about 1 year ago I popped a deer on the way to work. This took out the left front quarter along with all the electronics in that area, this was the first I saw of theses lights but a module mounted on that side was busted. Got the van fixed and no problem for 15-20,000 miles. The above mentioned lights came on and all the symptoms as stated from everyone are exactly the same . Shut the engine off and restart works for now. This has happened twice since the wreck on smooth roads with no rain or harsh conditions. One dealer charged to "reprogram" the computer and then told me they would start by replacing the in tank fuel filter, 500+ bucks.I think I will start by checking the engine grounds and the mounting of the fuse box which is oddly enough on the left side under the hood where the deer left his mark. It sounds like these people have a good lead on this problem and several solutions . If you have this same trouble please go to the first post and read all entries ,you'll most likely find your answer.
  • chucka4chucka4 Member Posts: 1
    2001 Yukon V8 reduced engine power error

    SPOT ON WITH THE HARNESS!!!!!!! My wife called today with the "reduced engine power" alarm. She restarted it and got it home. I found this website and this post. Took note and went to the connector. moved it around an got the same error. went and looked......YELLOW WIRE WAS BROKE!!!. Now, it looks to be about a 8 strand wire which was bent at the connection. I think that they should have used wire with more strand and made it longer to reduce the "KINK". I soldered a long piece in with more strands. Problem fixed.

    THANK YOU GUYS!!!!!!!!!!!!!!!!!!!!!!
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