Sonata NF (2006-10) :: 2009 - Abrupt Downshift At 20 Mph When Cold

My 09' has developed the abrupt downshift issue at 20 mph when cold. Once the transmission is warmed up, the problem goes away. There is a Service Bulletin on this problem so it is known and a fix is in place. The fix according to the Service Instruction is to remap the transmission software.

How this remap affected their vehicle. My car has been returning great gas mileage, and I am concerned that this fix could hurt that. If mileage is adversely affected, I'd rather live with the downshift IF it won't hurt anything.

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Sonata NF (2006-10) :: 2009 - Harsh Downshift To 3rd When Cold

I just bought a 2009 Hyunda Sonata, 4 cylinder limited edition with 82k miles on it about a month ago. It was maintained to the suggested maintenance schedule by Hyundai dealers prior to me owning it.

after about 2 weeks, it started having issues when slowing down. I narrowed it down to being a harsh downshift from 4th to 3rd when breaking when cold. After driving for 10 minutes it doesn't do it anymore.

My temporary fix is to manually downshift it into 3rd when I have to slow down. It seems to be that it stays in 4th too long and shifts late into 3rd, but I wouldn't think downshifting late would really matter.

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Sonata NF (2006-10) :: 2009 - Transmission Jerks When Automatically Downshifting

I have an 09 Sonata that jerks when automatically down shifting just before coming to a stop or slowing to make sharp turn. Car has 130k miles and I've never changed transmission fluid. BTW...it's been a GREAT car!

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Sonata NF (2006-10) :: 2009 - Tranny Harsh Downshift When Coming To A Stop

I have a 2009 2.4/auto with 32000...original owner...just noticed a weird tranny issue develop over this past cold week in NY...when coming to a slow stop the trans will harsh shift as it down shifts from 2 to 1...

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Sonata NF (2006-10) :: 2009 Hyundai GLS Won't Start / Fuel Pump Kicks On

2009 Hyundai Sonata GLS 4cyl 135k miles...

Everything has been going fine. On Thursday I stopped at a gas station. Came out and the car won't start. Had it towed back to the house.

It cranks, but won't turn over.
Fuel pump kicks on.
Spark plugs were worn, so changed them, can't hurt.
They spark, although it looks like it may be weak.
After changing the spark plugs and trying to start it, pulled them and you can smell fuel, so it is getting into the engine.

Checked the connections of the wire harness (all I believe)

Anything specific to this model that would suddenly not run. I drove it 3 times that day, no problems starting, running, driving, anything. So I'm kind of stumped on the sudden development.

The check engine light had been on, but I did disconnect the battery when I was looking at something else before I checked the codes. So it isn't throwing any now.

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Sonata NF (2006-10) :: 2009 - Gas Pump Continually Clicks Off While Filling Tank

I have a 09 sonata NF. The gas pump continually clicks off while filling the tank. I saw this issue discussed here before but I cannot find it. Has to do with a vapor canister and valve?

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Sonata NF (2006-10) :: GLS V6 Jerks Randomly

I have a 2006 Hyundai Sonata GLS V6. Recently the area I live in received 2 feet of snow and ice. I of course cleaned off all the snow and ice and started her up. I didn't drive anywhere that day since the roads were not clear. The next day I drove 15 minutes and upon reaching my destination's parking lot, the Sonata went into a jerking motion.

It seemed as if it wanted to stall out, like I was driving a manual. However it's an automatic. I stopped the car, and later when I went to leave it did it again. Once I got out of the parking lot and above speeds of 20 mph everything was fine. No more jerking motion.

The next day, after some time driving it does it again. My car never actually "stalls" or shuts off, it just jerks and once I can press the gas and go, it stops.

There are no odors or sounds and the car only does the jerking motion sometimes.

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Sonata NF (2006-10) :: Hard Downshift When Cold

My 2010, 4 cyl. auto started giving me hard downshifts awhile ago, when cold. Mainly going from 4 to 3, and 3 to 2. I had the tranny fluid changed a few months ago at 56,000 miles, but no difference. So, that left me with the dealer and this is their diagnosis:

Updated ECM and TCM and hard shift still present. Vehicle will require new PCM (TCM?) to resolve problem.

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Sonata NF (2006-10) :: Hard Downshift When Engine Was Cold And Under 30 Mph

My car also had the hard downshift when engine was cold and under 30mph. I seen where Sbr 711 had posted the TSB 10-AT-007-1

I printed this and took to the local dealer & also showed where it was mentioned as a recall.. The advisor looked up on his computer and showed no recalls for the 09 sonata?

I went ahead and scheduled the reprogram update and was told the technician can pull up more info on recalls than the advisor can? Any way they did the reprogram today and $89. later still no recall? How do I prove that in fact this is a recall & get refunded?

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Sonata NF (2006-10) :: Automatic Rough Downshift Into 1st Gear

My 09 Sonata GLS has 50k miles on it. I bought it as a demo model with 9k on it (regret that) as new ... who knows how it was treated.

at 40k miles I noticed that in the morning when I was braking the car would feel like it was slipping out of gear momentarily and it was pretty rough. After a few minutes it would stop and I could continue on my way. The car is an automatic. I noticed it if I let the car decelerate enough that it dropped into first on its own, or if I used the brakes. I figured it must be due to the cold weather or something and was hoping it would clear up. This was only happening after 8 hours of non-use, overnight in the cold.

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Sonata NF (2006-10) :: Rough Downshift While Coming To A Stop From About 20 Mph

My 2009 Sonata (4 Cyl.) has begun to downshift very rough while coming to a stop from about 20 mph. At first I thought it was the brakes, but now I'm convinced it's the transmission. Essentially it "jerks" a couple of times before stopping. It started happening at 30,000+ and only happens when transmission is still cold. Once I've driven for a bit it doesn't happen.

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Sonata NF (2006-10) :: 2008 - Jerks When Slowing To A Stop

When I slow down to stop my 2008 Sonata it jerks. It is an intermittent issue. The car has 95,000 miles and when I called the dealer I was told they would start with changing the transmission fluid and go from there. I read on some other posts of this same type of issue being fixed by installing the latest software for the transmission, but this was related to 2009 & 2010 Sonatas. Is it possible that installing some new software would work on my 2008?

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Sonata NF (2006-10) :: Transmission Jerks When Downshifting (intermittent)

My daughter has a 2010 Sonata with a 4 cylinder and an automatic transmission. She is pretty frustrated with an intermittent problem. Every once in awhile, especially if the engine is cold, the car jerks while slowing down. She believes it is the transmission when it down shifts. I have driven the car and have not been able to duplicate the problem myself. The dealer recently changed the mapping for the transmission in hopes that would work but it hasn't. The dealer hasn't been able to duplicate the condition either.

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Sonata NF (2006-10) :: Hard Downshift At Around 20 Mph - Electrical Hum Coming From Engine Bay

I have 2010 Sonata with 4 cylinder engine and 50,000 miles. For a while now, my car has a real hard downshift at around 20mph. When i put the car in shiftronics mode and do not downshift manually, at the 20mph hard downshift the car is shifting from 4th to 3rd. A while back i had the TSB for hard downshift and also did a tranny fluid flush. Neither has seemed to solve the problem.

Also, the car has a annoying electrical hum/whine that is coming from the engine bay. When i shift car into neutral the hum/whine goes away. Also sometimes when shifting into lower gears the hum/whine will go away for a short period of time.

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Mercury - Grandmarquis :: 1988 - Jerks Intermittently - Don't Downshift

1988 Mercury Grand Marquis

It jerks on occasion. Seems to do this at the point when it should downshift, but does not downshift. If I press down on the gas so that it downshifts then it runs fine.

Does it worst in cruise control. If I take it off of cruise control I can 'feel' when it is about to jerk and I can prevent it from jerking by either letting off on the gas a little bit, or pushing down on the gas so that it downshifts. Some of the time in cruise control it downshifts very smoothly.

It was getting worse and some good injector cleaner added to the gas seemed to solve the problem but it never did go away completely.Lately it has been getting a lot worse, mainly on moderate upgrades. Have not had a chance to get more good injector cleaner recently. The jerk is almost like the computer tells the engine to shut but then changes its mind.

1988 Ford Crown Victoria

Did a similar thing, mostly on fairly flat ground at around 35 MPH constant speed, when it seemed to be indecisive on whether to downshift or not.

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Sonata NF (2006-10) :: 2.4 Transmission - Clunk / Shake When Shifts And Downshift For No Apparent Reason

Well, After reading about the weird transmission issues these cars have...mine finally started to do it. It will clunk, shake the car when it shifts and downshift for no apparent reason. All of this does NOT happen all the time. The noises that come from my transmission do though.

I can have the car in Drive and have my foot on the brake and I can hear a grinding/low power steering fluid like sound that comes and goes. Its worse when I shift from Park to Reverse though. It sounds like air being released followed by a bunch of faint grinding noises.

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Avalon 2005-12 :: 2007 Downshift Immediately And Jerks When Apply Brakes

I have a 2007 Avalon and really enjoy the car. The only fault I can find is the weird shifting. It seems like every time that I apply the brakes, the car will downshift immediately and the whole car will jerk left/right due to the sudden downshift. Sometimes it will shift back up and cause the car to jerk a little but will be smooth after. Some times I apply the brakes and it does nothing.

I also get the occasional hard shift but the bigger issue here is the downshift while braking. It kind of ruins the driving experience on an otherwise great car as one tends to use the brakes often. It's especially annoying while going down a hill and applying the brakes. I have watched the tachometer before and noticed it jumps up to 3k or so from a normal 1500 or so RPM's. It may not be downshifting per say, but it's definitely doing something.

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Sonata NF (2006-10) :: Oil Pump Chain Position?

I had an oil pump failure in 1 2.4 L Sonata, 2006. I am ready to install the new oil pump balance shaft unit but cannot find where the timing marks on the pump pulley and crank should be? The service manual I bought simply says the correct position is critical. Any position or a simple diagram or link? It is a chain drive pump.

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Sonata NF (2006-10) :: V6 Water Pump Replacement?

I am trying to replace a water pump on a 2006 Hyundai Sonata, 3.3L, V6. But I hit a snag. I have removed the drivebelt but I can't get the water pump pulley off due to clearance. The water pump pulley is hitting the engine mounting bracket. All the manuals said I could remove the water pump pulley and the water pump and made no mention of removing the engine mounting brackets. I was wondering if there was a way to remove the water pump pulley, and the water pump, without dropping the engine and removing the engine mounts? If I do have to remove the engine mounts, do I need to remove the mounting brackets on both sides?

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