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Chevy Impala "REDUCED ENGINE POWER" message



  • i am having same issue with my 2010 chevy impala. i contacted gm dealer headoffice told them if i get killed or someone else ill sue them for everypenny> i have contacted a lawyer he said i got strong case. they sell these iece of [non-permissible content removed] and there is so many ppl on saying same thing happening to their impalas.they are ignoring it only want the money if will be funny when they have none.when ppl sue them
  • jlg7jlg7 Posts: 16
    Im having the same problem with my Chevy Traverse. GM really needs to step up to the plate and do a recall on this issue before someone gets killed in an accident. Same problem seems to be happening in the Saturn cars and Equinox too! Hey GM since you monitor these boards, YOU need to fix this problem now!!!!! :lemon:

    I have the same promlem, mine is included with Traction control needs service.
    for icy weather, when its warm no problems but suxx in the winter I love my chevy but dont know what to do went to garage change wheel bearing but came back shortly after
  • lil100lil100 Posts: 12
    Now I am having trouble again with my Impala - just had the gas pedal replaced - now apparently it's the gas caps or something. This is ridiculous. I think I"m going to write a letter to write letters to newspapers and tv news shows. If GM is not going to do anything - we need to start doing something.
    Very unhappy.
  • trumble09trumble09 Posts: 13
    edited February 2013
    Battery didn't help after a weekend test drive "Reduced Engine Power/Service Throttle" were back, My dad started tracing wiring and found this in the PCM Box.

    PCM Pic 1
    PCM Pic 2
    PCM Pic 3

    The Blue in the terminal is a bunch of Icemelt salt that had found its way into the airbox with water and rode the wires down into the PCM plug and corroded some terminals, including the Throttle body wire connection. He cleaned the terminals with air and got the corrosion off them and the gunk out of the plug and got the moisture out and for 3 days my car has been running with no hiccups even when the traction control has kicked on a bunch of times on slick snowy roads (which caused the reduced engine power before) The PCM is located in the bottom of the airbox as it requires air to cool it, although it doesn't require salt. Someone who owned the car before me apparently had the PCM box off ripped a gasket and put it back on with half a gasket. Luckily so far it doesn't seem like permanent damage was done to the PCM.
  • gmcustsvcgmcustsvc Posts: 4,251
    Hello dandd2009,

    If you need assistance locating another dealership in your area to get this looked into, please let us know! Send us an email at with your request and ZIP code.

    Sarah, GM Customer Service
  • gmcustsvcgmcustsvc Posts: 4,251
    Good morning newhaven,
    Was your garage one of our GM dealerships? If so, we'd be happy to follow up on your visit there. Please email us at (include your name and contact information, the last 8 digits of your VIN and mileage, and as summary of the situation so far).

    Sarah, GM Customer Service
  • I have a 2011 Chevy Impala LT, I have been experiencing 3 messages SERVICE STABILITRAK, SERVICE TRACTION CONTROL AND REDUCING ENGINE POWER. This has been going on for months and the dealership wants to charge $129.00 for diagnostic. I took it to Autozone and got it for free. Just as I suspected that the Throttle Position Sensor (TPS) is broken or burned out. I also did a google search and found that many others are having the very same problem. The car would jerk and downshift. This morning I also received another message after I pulled over, STARTER DIABLED, SERVICE THROTTLE. I had to wait for minutes before starting again and 15-25 min there after.
  • Look at my posts above I had the same issue, my throttle body was covered under the powertrain warranty but after 2009 they removed it. If you're still in bumper to bumper it may be covered, if not you can review other posts for cost of a replacement throttle body. They replaced my throttle body and it persisted. Other possible causes for the throttle body code include a bad throttle body wiring harness, or a gunked up PCM plug like we found in my car.
  • I recently bought a new 2012 Impala LS and am very happy with it so far. I like to read up on issues with my cars and often check the different forums to see what the latest issues are. I also own a 2006 Toyota Matrix and just had some recall work done. This is from TOYOTA:

    The ECM for certain 2005 through 2008 Toyota Corolla and Corolla Matrix models equipped with the 1ZZ-FE
    engine and two-wheel drive may have been improperly manufactured. There is a possibility that a crack may
    develop at certain solder points or on varistors on the circuit board. In most cases, if a crack occurs at certain
    points or on certain varistors, the engine warning lamp could be illuminated*, harsh shifting could result, or the
    engine may not start. In limited instances, if cracking occurs on particular solder points or varistors, the engine
    could stop while the vehicle is being driven which may increase the risk of a crash.

    The end result of this failure seems to be very similar to the Chevy reduced power problem many owners are experiencing. The vehicle may shut down at highway speeds and cause a crash.

    My point is Toyota has seen the problem and is trying to correct it. I hope to get many good years of service from my Chevy but I also hope GM recognizes the problem many of their customers are experiencing and does something about it. I plan to remain a GM customer since I think they still build a quality product. I can see how many of the people on this forum are getting frustrated with this possibly life-threating problem.
  • I'm having the same trouble with my 2011 Malibu. Service traction, engine power reduced and engine esc lights all come speed 50mph an once it's running below 20 the car feels like its going to fall apart. With only 55k miles I shouldn't be experiencing such a problem! Seems to be a huge problem many People are experiencing!
  • Gmoney, what did it cost you to have the TPS replaced? Thanks!
  • I am having the same exact issue where the car will suddenly say service traction control..esc...reducing engine power. I have 39,000 miles on the car and it's out of bumper to bumper. I took the car to chevy dealership and they said it was the throttle body and that they would cover under powertrain even though it's not included in that. The problem is the part is back ordered and it's been 8 days and they say they dont know how long it will take to get the part because they have over 4,000 orders for this part. Chevy has known that this was a problem yet they did nothing about it... it should have been recalled. I have to get a rental car cause this is undriveable and i could have to have the car for up to a month. What i'm probably going to do is take it to a mechanic and pay to have them fix it and then file a suit in small claims court against chevy for knowingly putting faulty equipment into there vehicles. I sent a link to this page to chevy and also had constant contact with them about this issue. I would love to get some of the people from this forum and other forums of people with the same issues and see if a class action lawsuit can be taken against chevy.
  • I was told by my local Chevy dealer that it would cost me 99.99 for diagnostic I went elsewhere-where I was told it would be $20 for a diagnostic test...anyway the problem was a sensor that just needed cleaning...we went through a car wash and the next warm day it was fine...took it in today for repairs and the guy didn't charge me a penny told me to save my money and come back if the problem reoccurred! Don't pay out your hind end go to auto zone and get a free diagnostic test...dealerships are a rip off
  • I have a 2009 impala as well and we are having the same problem. While driving the service traction control/ and engine power reduced comes on. Also, the car will just shut off and say started throttle disabled. As I read so many people are having the same problems that I am having. Yet GM is ding nothing to fix this problem. Sounds to me that there needs to be a recall on this so the problems can be fixed this happened to me while driving on the interstate with my 3 children, I just thank god that I was in the slow lane so I could make it to the side of the road before we got hit. What is it going to take for GM to admit that something is wrong and fix their mistake, someone being killed or hurt?
  • gmcustsvcgmcustsvc Posts: 4,251

    Will you be working with a dealership to get this checked into? Please let us know if we can be of any assistance! We can be emailed at (include your name and contact information, the last 8 digits of your VIN and mileage, and a summary of the situation so far).

    Sarah, GM Customer Service
  • Not sure as of yet. I would say no, dealerships want to charge way to much when you can get the job done for less. The only way that I will take it to a dealership is that GM pays the bill. After all the trouble that I have had with GM over this, I will not longer purchase a GM vehicle. There is apparently a problem with the chevy impalas and GM does not want to fix it.
  • jwade05 I talked to a district rep from chevy today and i told her the previous person i talked to had told me that they had over 4000 orders for throttle bodies and she actually told me that was on the low end and its alot more then that. This should have been recalled on the impalla and the malibu. My car did the same thing the first time and i was on the freeway also. I have purchased 6 cars over my 23 years of driving and 5 have been chevy's.... this is seriously making me consider going to a different car manufacture
  • i am having service traction control and engine power reduced problems......i need help......i dont know what the part is that makes it do it......please help
  • I just got my Impala (used) in July, and I've already begun having issues with this "service stabilitrak" message and "reduced engine power" message. It had about 39,000 miles when the problem started. The first time it happened, I was driving in town and didn't really pay it much mind as it didn't really affect my driving, and eventually after a few days the check engine light went off. I did research it and from some of the comments I saw at first, I thought it would be ok, until I was in the middle of Georgia on the highway during rush hour and the message came on and eventually the computer shut down the throttle and the car slowed down and stopped. Fortunately people around me were paying attention and allowed me to pull over before the car stopped completely so no accident occurred, but it was very scary. I shut the car off and after a few minutes was able to continue, but this shouldn't have to occur. The light has come on twice since then, and usually within a few days the service engine light goes off again. I haven't taken it to the dealer because without the service engine light on, I am pretty sure they will have trouble diagnosing it and the light always goes off before I have time to take it in. It happened again last night, and even after the car was shut off and turned back on (which I have learned to do), the reduced power message remains. I am planning to take it to the dealer, but I can't afford to pay repairs out of pocket so I sincerely hope this issue is covered by warranty.
  • from reading the other posts on the forum, I believe it is something throttle related. I have the same problem with my 2011.
  • gmcustsvcgmcustsvc Posts: 4,251
    Keep us posted, cjq11983. If you want for us to check into anything further with you on this, don't hesitate to email us at with more details (including your name and contact information, the last 8 digits of your VIN and mileage, and a summary of the situation so far).

    Sarah, GM Customer Service
  • I am also having the same issue with my 2006 impala. I bought this car brand new in 2006 and I have not had any problems until two years ago when my car started to slow down while driving and then the message appeared engine power reduced. It did it a few times that year and then it never happened again until a few days ago. Please keep me updated with your progress on your impala!
  • I am having the same issue. Just started today. Wouldn't this be covered under the Powertrain warranty? I bought Certified Used to not have these problems. But I am past the Bumper to Bumper.
  • dasupadasupa Posts: 13
    How strange that Toyota's hybrid had problems with its acceleration and not only was there a recall, they had to pay millions of dollars (just heard it on the news last week). Yet, Chevy has a very similar issue (instead of sudden acceleration, we get sudden deceleration) and not a word is spoken by anyone but the victims.
  • gmcustsvcgmcustsvc Posts: 4,251
    Have you had this checked into at any point over the last few years that it's been happening, rbowens?

    Sarah, GM Customer Service
  • gmcustsvcgmcustsvc Posts: 4,251
    If you have questions about warranty, nighteagle79, we'd be happy to get you more information. Please email us at with your name and contact information, the last 8 digits of your VIN and mileage, and summary of your inquiry.
    Sarah, GM Customer Service
  • gmcustsvcgmcustsvc Posts: 4,251
    Depending on when your vehicle went into service and how many miles it has on it you may still be within your bumper to bumper warranty (3 years/36000 miles). Please don't hesitate to email us at if you have any questions! Include your name and contact information, the last 8 digits of your VIN and mileage, and a summary of your inquiry.
    Sarah, GM Customer Service
  • Just had the same issue as most of the posts I have seen. Started the car, and it ran horribly, with the messages; service traction control, service stabilitrak, reduced engine power, and the check engine light was on. Took it to the Chevy dealer, and he was not surprised. He made the comment that "these cars each have a personality of their own", and "this problem occurs more often than you know" after I mentioned that there were hundreds of complaints on the internet. He said it could be one or more of about 4 things. Unfortunately, the car has 60,000 mi. (2010 model) so it is out of warranty, but this is a safety concern. I do a lot of highway travelling, so I really don't want this to happen again at 70mph., and I won't let me wife drive the car until I know it is fixed. I am waiting right now to see what the service dept comes up with. I will post their "fix" once they get back to me.
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