My girlfriends Tucson recently started having some funny shift issues. It's kinda like a slipping tranny or at times it has problems upshifting at it's normal intervals.

I am a mechanic. I'm not a Hyundai certified tech, but I know cars and this isn't right. It's not terrible, but the car only has 1500 miles left on the warranty, so I thought it would be a good idea to get the complaint on record in case the dealer blew it off and the trans went belly up after the warranty expired.

As I predicted, the dealer has made an excuse that there's a problem with the IAT sensor and because of that, he cannot proceed to troubleshoot the transmission until that is repaired. Naturally, this sensor is not covered under warranty and he wants us to shell out ~$500 to replace the sensor before he will inspect any further. There is also a bad brake sensor (not sure what it's called as I didn't speak with the dealer) that's causing the ESC light to come on periodically. This sensor is covered under warranty so I told her to go ahead and have them replace the warranted part and we'd take the car to another dealer to get the trans looked at.

Does this sound fishy or is there really some legit explanation for how the IAT sensor can contribute to transmission problems? At this point, I'm at least glad that we have the malfunction on record with Hyundai. In case this does not get resolved before the warranty runs out, I want to make sure that someone had been made aware of it in time to have done something about it while the warranty was still in effect.

Currently, the dealer is replacing the faulty ESC (??) sensor and explains they are going to "run a relean & reset the tranmission shiftmaps to factory memory". I feel at least the ESC issue could be a step in the right direction rather than blaming some random sensor that threw a code in the computer once or twice.

Anyone have any thoughts?

 

What are the exact codes recovered ? Surely they noted the findings in the CCR of the customer' invoice..

#1 -- IAT code,,, don't replace a thing... install GDS and update the PCM per 09-FL-007 :




• Model: TUCSON (JM) vehicles with 2.0L gasoline engines.

2006 should be #139


What is the ESC/ABS codes ?? There is campaign 092 for brake light switch replace, this will goof the ABS/ESC with a C-1513 code, and it will shut down a CAN COMM line too because of switch code.. all this needs to be cleaned up. If it has a primary pressure sensor code, dont replace the sensor on master cylinder, it is result of switch logic..

Let them reset the "ADAPTIVE VALUES" for A/T after other stuff is cleaned up, ask them to do it with trans fluid at operating temp, then ask them to do the "initialization of the learn process after reset with hot fluid so it start learn process during test drive at no more than 25% throttle with GDS attached to watch throttle % while doing the initial learn before returning car to you... they should be able to file claim for GDS and reset, so don't let them charge you here.

 

Thanks sbr711! That was a very thorough and informative response. It sounds like that's what the dealer did and the tech told her it was their first response in troubleshooting trans problems. GF did notice an improvement in trans performance, but we'll continue to keep a close eye on it and take it back if any shifty-ness continues.

Thanks again!