My wife was driving her 2002 Sonata yesterday when it began to act up. I'm not sure if the Check Engine Light came on before or after the transmission started to act up. She says (I haven't had time to drive it yet) that the only way to make it go is to manually shift it up once (in the Shiftronic section). Is it possible that it is an engine issue that could cause the transmission to act funny? This has 130,000 miles and a V6. Unfortunately we just last month had the timing belt and water pump replaced. Would the CEL come on if it was a transmission issue? I've never seen that before, but then I've never had a transmission go out on a newer car like this.
Thanks,Scott

 

Anyone? Anyone??
I drove the car Friday night. It will go into Reverse just fine and back up just fine. So, I backed out of the drive, put it into Drive and it...went nowhere. The tach raced up as I tried to move forward. I didn't over tax the engine. Not to worry. I then moved the lever into Sport Mode (and did nothing else) the car moved forward as normal. It acted like it didn't want to upshift while in Sport Mode, but maybe that is normal? So I moved it back to Drive and the transmission shifted up like normal. I drove it this way around town and a little on the highway. The engine runs smooth as silk. And...NO Check Engine Light. When I got home I checked the transmission fluid. It was at the proper level, slightly orange and smelled odd.
I called our local (50 miles away) Hyundai dealer and he gave me his best guess: If the CEL is NOT on then it is likely a fault in the transmission and it's time for replacement or rebuild. If the CEL is ON then it is possible that it is a sensor issue and no big deal.
So, that is what I have found out. What do you think? I've never seen anything like this. I don't even have to move the lever while in Sport Mode and it will go. When I pull up to a stop it won't drop into 1st unless I were to move the lever over to the right into Sport Mode. Is it a short somewhere? Thanks,Scott

 

If its working okay in the manual mode then I don't think there is anything wrong with the transmission itself. The problem is likely in the shifter assembly. When you shift into Drive the transmission is not recognizing that and is staying in neutral.

If you are able to shift through the gears okay in manual mode and somebody is telling you that you are going to need a transmission rebuild I would be very leery of that.

 

That is the most encouraging news I've heard so far! One thing I can't recall, and I have an XG350, is the transmission supposed to upshift like normal while in Sport Mode or will it need to be done so manually? It seems to want to stay in 1st till I shift it or move it to 'D'. I can't recall if that is normal. I don't use Sport Mode as I drive like a Grandpa.

 

Is this hard to replace? Anyone on here ever had to do it? I'm calling around to salvage yards to see what is available. This may be fixable. Would a Chiltons manual have any good photos of this? Thanks,Scott

 

That'd be normal.

The transmission is supposed to down shift while in manual shift mode (sport) if you allow the car to slow down too much for any given gear. I've not tried to redline the engine in manual shift mode to see if it would upshift automatically because I don't like to needlessly abuse my car. I suspect it will not upshift under those conditions and don't care to test it out.

 

TCM will request use of MIL from PCM... If MIL been illuminated at any time, code(s) is stored somewhere... find a 1529,,, then you need to access the TCM for the trans codes...

Start there and report back with codes recovered.

 

Ok, the next time I'm able to I will put a code reader on it. O'Reilly's said they couldn't read it if the CEL wasn't on. Not sure I believe that, but I have a friend who is a mechanic, but is recovering from surgery. Maybe I could have him look at it. I did drive it in to work today. It made it. I did notice that sometimes while in 'D' it will creep forward under light throttle and then if you give it more it will rev up and stop moving till I move it into Sport Mode. Not encouraging. Thanks,Scott

 

The CEL came on last night on the way home so I was able to get a code reader on it. I found this: code # PO755 shift solenoid B
code # PO750 shift solenoid A

So, what's next for this car? Thanks,Scott

 

Replace the wire harness inside the trans case (grey connector on the case) for the solenoids,,, you not going to like the cost either.. and what it takes to replace it.. I hope you not mind removing side pan and valve body.. then be aware of the linkage and screen that will fall off trans case when valve body pulled off. You need to do this so the grey plug will pass to get it out.

Replace the 2 solenoids also.. they not terribly expensive..

You will need a torque wrench, RTV, and SP-III to refill trans.