Three problems related to transmission not engage have been reported for the 2010 Hyundai Santa Fe. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2010 Hyundai Santa Fe based on all problems reported for the 2010 Santa Fe.
Dealer reflashed (upgraded?) the computer during an unrelated door lock repair. Afterwards, the transmission disengages at low speed/coasting, then reengages violently. When requested to restore the computer to the original factory program, the dealer said it cannot be done. There have been subsequent reflashes installed to improve the situation, but to no avail. Dealer says "the computer just has to learn my driving habits". It's a dangerous situation when you're not aware of the disengagement, the engine rpm increases, then a sudden engagement occurs.
I was accelerating while entering traffic from a side street and the computer for the transmission put the transmission in neutral. I lost power as the engine rpm spiked up. The transmission was still in drive and the transmission did not engage again until I took my foot off the accelerator and then reapplied it. Aside from this problem being a vehicle defect, this situation could have caused an accident. I have taken the vehicle into the dealership twice for this problem since the end of July. The first time I took it in the dealership was able to reproduce the defect but they could not reproduce the defect the second time. Unfortunately this type of failure does not show up in the cars computer. Each time the car was returned to the dealership the transmission software was updated and the car was driven for a period of time as a relearning exercise. Obviously this did not correct the problem and without a failure code in the computer to pinpoint the problem the dealership is unsure which computer or component needs to be corrected. With this defect this vehicle should not be on the road because of the risk of an accident.
As the engine starts with the gear shift in "park", the 2010 sante fe lurches forward as if the transmission has not disengaged. The forward lurch ranges from a sensation of motion to an inch of tire rotation. Furthermore, this happens again when the vehicle is in motion when idling between 1200-1500 rpm and when accelerator is released and pressed again at around 20 mph to 25 mph. It has happened at speeds as high as 40 to 45 mph. It feels like someone bumped into me from behind. In one instance I quickly applied the brakes assuming I was rear-ended.