I have a 2011 Sonata SE (paddle shifters for manual shifting), 2.4 with 174,000. One-owner and well maintained. Transmission fluid changed every 40,000 miles with Amsoil.

Problem:

The transmission when in "Drive or D" will sometimes switch to manual mode while selector is still in "D". The dash will show the gear the transmission is in and often attempt to further downshift for no reason. If I don't shift the stick into "Manual Mode" then back to "D", I fear it would shift down until the engine over revs. When I try to switch to the Manual mode and input an upshift, the transmission is finicky on shifting out of the gear it is in, and often ignores the input or just downshifts if it does respond to the upshift, shifting up. I have to move the console shifter back and forth from Manual to "D" to get the car to stay in the "D" mode, but the transmission often reverts back to the manual mode even if in "Drive."

I have scanned the computer and no codes related to the transmission are read. The car has a seat sensor for the SRS, but it has been on for a while and never produced this problem, it just generates a light on the dash with no issues but that the SRS is not working.

I'm thinking about changing the input and output sensors on the transmission, but thought I would post the problem on the forum to see if there is a solution to this issue. Any thoughts are appreciated as I won't work on the car until this weekend.

Thanks,

Barry

 

Hi Barry!
I'm having the same problem with my 2011 Sonata SE. Did you ever get the issue resolved?

Thank you!

Sean

 

Hi Sean!

I had the same issue with my Sonata SE. It turned out the problem was with the transmission range sensor (also known as the shift position sensor). I replaced that sensor, and the problem was resolved. This might help in your case too!

 

Hi Yernaz!
Thanks for your reply! Where's the transmission range sensor located? (I want to make sure I get the right part)

TIA!
Sean

 

You're welcome! The transmission range sensor on the 2011 Sonata SE is typically located on the outside of the transmission, near where the shift cable connects to the transmission itself. It's mounted on the transmission housing, just below the battery tray. To access it, you might need to remove the air intake or battery, to get a clear view and working space. Make sure to get the sensor that matches your specific model year and engine type.

 

This look like the one? It's got quite a few names:
https://www.jimellishyundaiparts.com...270026700.html
(The caveats for the application of it are funny! I'll call the dealer and get the part based off my VIN.)

FWIW, every time the dealer touched the car, only for recalls, something stopped working: the first recall paddle shifters stopped working. Second recall, the computer/steering wheel controls stopped working. Hyundai is like a British car, but Asian. lol.
You have similar experiences?

 

Yes, that looks a lot like the one I used a few years ago. If it's the same sensor, replacing it should help fix the issue.
And yes, that has happened to me sometimes. After taking the car to the dealer, new issues would pop up, even if I was just there for a routine service or a recall. It can be really frustrating!

 

Hi Yernaz,
I replaced the Automatic Transmission Gear Position Sensor, part number, 4270026700. And unfortunately it didn't fix the problem.

I found this video talking about common problem's with our cars. At this part of the video, he talks about the Vehicle Speed Sensor being a common problem. I'm going to look into replacing that now:

Thanks,
Sean

 

Sorry to hear that replacing the transmission range sensor didn’t fix the issue. Since that didn't solve the problem, the next steps could involve checking the wiring harness for any loose connections or damage, as well as the shifter assembly itself. There might be a fault in the shifter mechanism that’s causing it to switch between modes unexpectedly. If those seem fine, it could be worth looking into the Transmission Control Module (TCM) or even a software update for the vehicle's computer

 

I'll try that. If I had the right computer analysis software/hardware, one could determine the source of the issue. I'm going to check with the dealership to see if they can determine the source of the random downship.

Thanks!

Sean