'09 Sonata (I4 GLS) Transmission Jerks while downshifting when cold!
 

Hi all,

I have an '09 Sonata (I4 GLS) with 33k miles on it. Bought new and am the first owner. Drive it a lot and use both auto and shiftronic modes. Lately, the tranny is giving problem. When the engine is cold and the car comes to a stop, it gives a big jolt when downshifting, at lower speeds, (while downshifting from 3rd to 2nd gear). I've noticed it occurs when the speeds reaches to around 35-30 mph and (I think the tranny shifts from 3rd to 2nd). I tried it by downshifting manually (using shiftronic mode) but couldn't replicate the problem. Took it to the dealer who couldn't replicate the problem. Did the 30K service which included the tranny flush but that hasn't solved the problem either. The problem only occurs when the engine is cold.

Any clues? Anybody else have the same issue?

Is it possible that while downshifting it downshifting to 1st instead of 2nd ? is there anyway to tell that?

Thanks.

'Stuttering' of the TCC (Torque Converter Clutch) lock-up solenoid in the cold temps??

.... hmm I don't know if its the TCC. Went on another 800 mile trip over the weekend and on the 2nd day (after a 10 hr strop), started the car and it did the same thing. The difference was it was doing it even after the engine was warm and it was so bad that I had to use the shiftronic. Didn't go back to auto again for the whole trip. But today in the morning, it only did it 2-3 times while it was cold and then smooth shifting.

have you serviced the trans yet?? some trans systems are very sensitive to the fluid level and condition. fresh fluid may be just the ticket. if the trans has been service recently, and this has developed since, it could be due to an incorrect fluid being used. you will need to check the fluid used if this is the case. your owners manual will be able to specify what fluid rating should be used for your vehicle.

df

Yes, I had the 30k service done at the dealership and it included transmission flush etc so the oil level is correct (I've been checking it regularly) and it was correct spec oil as well .... and I'm still stuck with the problem

sorry, i re-read the original post and saw that the trans was serviced. it's a good thing it was done with the proper fluid, though, as that can sometimes be a cause of this sort of thing.

i would say keep accurate logs of when this occurs, so that way you can get the proper information to the dealership so they can look at it. they may need to keep the vehicle overnight to drive it cold, though, especially if it is an intermittent problem.

accurate logs would reflect the ambient temp, distance from the start of the drive, and whether the vehicle was under load (uphill) or not (downhill) or just flat regular roads.

best of luck with this.


df

I have the SAME issue!
 

I have the same problem. It isnt related to the car being warm or cold....its the outside temperature. (Look up "09 Sonata transmission downshift" on edmunds for others with same issue....that have had it fixed). I had the problem fixed last month by having the dealer reset the computer. It came back last week! I was going to take it in again today, when the problem magically went away on my way home from work. The difference? Today its 75 degrees. It hasnt been anywhere NEAR this warm in months...(Or as I soon realized, since the problems began to occur in the first place). I have 63k miles on my car, and most people with the same problem have varying mileages.... The only common issue seems to be the weather. Needless to say......alot of people have been posting questions like yours in the last few months... . One post recommended "updating" the computer, not just resetting it. This person claims it is a permanent fix. Lookup "09 Sonata transmission downshift" on edmunds for more info on this. I have an appointment set for Friday, and a few blog postings printed out for the dealer so they know the problem is widespread. Hope this helps!

09 Sonata Trans issues
 

Good reading here. Just had the adaptive learning reset on my 09 for similar complaints. (2009 Sonata GLS, I4, 12k miles) Definitely have a hard 2 - 3 upshift (sometimes hard downshifting too). Also, mine drops into 5th early (38 - 42 mph) then lugs. Have to put a lot of foot into it to get a lower gear. Dealer seems a bit clueless. As stated above, reset the adaptive learning which seemed to make things better for about a day. Then back to lousy shifting.

Does anyone know of a TSB that might speak to the issue. It would be nice to know more when speaking with the service writer next time a make the 60 mile round trip to the dealership.

The remedy --- no further complaints heard yet
 

Itis not a fluid-service issue.

It is not a TCC issue.

I have done at least 5 of the 2009 4 cylinder auto trans has a harsh down shift 1 or 2 times after cold start, and fine the rest of the day until next cold start up........

When inspected with GDS, likely/almost always there is no DTC, thus system is operating within normal parameters.. program logis is that the duty cycle for solenoid(s) is not long enough to slip the shift (smooth) and instead the solenoid is just being turned on (click.. full oil pressure.. thunk as the clutch pack engages quicker)..

Here is the repair... Install the 2010 model update (it is a campaign for 2010 cars)... There is NO APPLICABLE updates that come up on GDS in ECU Upgrade.

The programs you need is #160 for the engine control, and #161 for the auto trans control.. Have tech call assist, and get a case number related to your car, and they will tell tech how to put the 2010 updates into the 2009 car (cannot be done automatically).

Advise them to print the GDS screen showing the program #160 in the event line, and do same for event #161..... take these 2 prints and attach to repair order as documentation to what was done so DPSM will authorize payment.

After the updates is installed ----> Reset the ADAPTIVE LEARN for the auto trans..... DO NOT reset adaptive learn for engine.. I had to do the whole process over.

Thanks! Great detail WIll post again once I run this past the dealer Service Mgr.