Asked by Jul 05, 2011 at 10:06 PM about the 2009 Hyundai Sonata V6 GLS FWD

Question type: Maintenance & Repair

I have a 2009 Hyundai Sonata purchased new and currently have 55,000 miles.  At approx 20-25,000 miles the car started misbehaving.  When reaching a speed of anywhere from 40-65 mph, I would take my foot off the accelerator expecting my speed to reduce, only to have the car continue at the same speed all the while the RPMs would rapidly drop and immediately pick up though I stepped on the accelerator.  The RPMs would continue to do this until I actually stepped on the brake drastically reducing my speed.  I gave in and took the car to the dealer.  $228.00 and a day later, I was told that I had a "Gummy Throttle Body" that they had to clean.  Well, the car has just started behaving in the same manner!  I am a single woman and don't want to be taken advantage of!  Is there something that I should be doing differently in order to avoid this issue???  Is this a common issue with this car?  Any words of wisdom would be greatly appreciated!  

14 Answers


First of all why was that not covered under the warranty? and it still should be. If not fixed to your satisfaction bring it to a different dealer ASAP

2 of 2 people found this helpful.

Thanks for your reply Joe! Those were my thoughts as well! Thus the reason for taking the car back to the dealer. So safe to assume this is not a normal issue?? I'll go back to the dealer again and complain as well as question the warranty. If no satisfaction, I'll go elsewhere and try.


Absolutely not a normal issue. I have an '07 Sonata and love it, have had no problems whatsoever with the dealer, partly because I factored that in (the dealer) before making my purchase...the big highway store super showrooms tend to do a lot of sales volume but don't normally do so well on the service side.


O.K. Joe...two weeks later and I'm here with an update hoping for your input yet again :) I finally got to a different dealer this past weekend. When explaining my issue I was asked if this was the first time having this problem. I was honest with them...told them it happened at approx. 25,000 miles at which time I had taken it to where I had bought the car. I told this guy that I wasn't going to tell him what the first dealers so called diagnosis...but that I wanted them to look into it blind so to speak based solely on what I provided them with as well as what they witnessed from the car. He understood, agreed, and scheduled me for this past Monday. My entire ride there consisted of the car doing "it's thing". Would you believe when I took the tech for a ride it didn't misbehave?!?!?!? Not even once! Grrrr So we went back to the garage and he hooked it up to the diagnostic thing to see if by chance any codes came up even though I had no lights on. This is what my receipt states. "SCANNED FOR DTC FOUND PO449 EVAP EMISSION SYSTEM VENT VALVE RESET TCM ROAD TEST OK AT THIS TIME" I was told that it may or may not have anything to do with the way the car was behaving. Um...ok? Well, this took place Monday. Today is Friday. I'm shocked to tell you that the car hasn't been doing the rpm thing since Monday when they reset the TCM. So did that correct my problem? Permanently? Temporarily? If a code appears when they do the scan, doesn't that mean that there's a problem and a repair and/or replacement is needed rather than just resetting the TCM? (whatever TCM is) NEW ISSUE! Related to them doing the reset or just a coincidence? Extremely high heat today of approx. 105! Left work and drove approx. 30 mins with the a/c on and fan blasting. Had to stop at UPS so the car was turned off for approx 10 mins. Started it back up to leave. Drove approx. 5 mins when to my surprise my check engine light came on! First time ever for a light of any kind to come on! So again, totally coincidence? Or could this be related to the reset that was just done 4 days ago? Or heat related...even though the temp gauge was normal. sigh Getting slightly frustrated. Sorry...didn't mean to write a book :(

1 of 1 people found this helpful.

Of course it won't misbehave when you bring it to the mechanic, don't you know that? OK -- sounds like they did the right thing, a scan (first), found a code and fixed. It is possible, but not guaranteed, that was the problem. A code means there is a problem but it doesn't necessarily mean a repair, it could be just a reset, and with today's electronically controlled engine computers, all it takes is one part to be out of whack and car just won't run right. So hopefully that was all it was for the throttle issue, have to wait and see; just like anything else, some mechanics/dealers are better than others. As for the new code, it's hard to say but a wild guess is it's unrelated to the other issue. Only way to know for sure is to run another scan. If you have an Autozone store near you sometimes they will run your scan for free and on the spot. Check engine light could be any of literally hundreds of things, even a loose gas cap.

1 of 1 people found this helpful.

Oh TCM should be (I think) Throttle Control Module, so that's why it was likely related to or the direct cause of your throttle issue.

1 of 1 people found this helpful.

I'm still amazed, but yes! It was in fact the gas cap! I'm guessing with the extreme heat we had yesterday that my cap loosened a bit?? Who would have thought that something like that would result in a check engine light! Re: my initial issue...knock on wood, but the car has been running as it should be since the reset. I want to thank you so much for your words of wisdom! Don't write me off just yet though :) I'm sure I'll be back with more concerns. You've been great Joe! Thanks again <3

1 of 1 people found this helpful.

The TCM is the transmission control module. This model Sonata has ETC (electronic throttle control) that is controled directly by the PCM (powertrain control module).

3 of 3 people found this helpful.

They charged $228 to perform an induction cleaning?!?!?!?!?!?!? When I worked at a Chevy dealer, we thought the $60 we charged was a rip off.

1 of 1 people found this helpful.

Far too many acronyms for me! All I know is that I have a Sonata, and my receipt states that they reset the TCM.


Well, considering I paid the $228...I would have gladly welcomed the $60 ;-) Makes me sick now though to find out that I should/could have refused to pay considering the warranty. That along with the fact that they didn't even fix the problem. I'm talking as though the issue has been resolved! Still keeping my fingers crossed after taking it to the other dealer and the reset was done. It's been 6 days and no issues so far :)

I have a 2009 Sonata as well. My car is in the shop for the tcm as well. My car wouldn't drive past ten miles an hour and finally quit all together. If they try to charge me for anything, I am going to yell loudly. It is covered under warranty!


having worked on this particular brand for the last 10 years it sounds to me like you have a problem with the throttle position sensor. it is a newly available part from hyundai( you used to have to replace the entire throttle body). there is also a reprogram for the ecm(engine control module) that goes with it. with you having the problem in the past the dealer should have no problem getting the repair covered even if you are out of warranty.after 10 years i have some strong advice to anyone who reads this post. if you take your car to a dealer for repirs and are just outside of warranty ask your service advisor if hyundai will do anything to help you out with the repairs. if its a small repair most of the time in my experience they will cover the repairs entirely. i have also seen 50/50 splits with the customer. but you will never know if you dont ask. they will not offfer this to you you will have to ask. oh and inside of every hyundai wners manual is huyundais consumer affairs hotline. this is your number to call and complain about anything youd like to

5 of 5 people found this helpful.

Hi,I have a hyundai sonata 07&since I had the car...It's giving me trouble.When I stop at a light or stop period with my foot on the brakes,it's make a strong vibration.Would I need motor mounds

1 of 1 people found this helpful.

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