Hello, purchased used w/30k miles. For a period of 6 months my "speed shift" option would engage without prompting, requiring me to shift and would not go back to "automatic mode" and then would mysteriously go back to auto on its own! We were not knowingly activating this feature and tried everything to control option ourselves to no avail. Dealership could not get it to do this or throw any codes on 3 separate occasions. Has not been happening for past 2 months, however, don't trust it not to reoccur! Any ideas? Thank you!
slips into manual/shift from automatic on own & won't allow us to decide on 2007 Hyundai Sonata
by janeyoung13 in Hastings, MI on June 25, 2010
ANSWER by dandd on June 25, 2010
This sounds like the mode switch is acting up, this is the switch that controls whether you are in autoshift or select mode. I would carefully inspect the mode switch and play around with it to see if you can get it to malfunction. Some of the contacts may be getting worn. I would also do this with a scan tool connected while reading the data to see if you can 'catch' the switch malfunctioning.