Hyundai Repair: 2005 Hyundai Sonata Malfunction Ind. Light, 2005 hyundai sonata, malfunction indicator light

Question
HI,
My Malfunction Indicator light just came on. A week prior I notice 2 to 3 times where my car would "jerk/lurch" while driving. Almost like stubbing your toe and stumbling. It just lasted a few seconds. Not sure if I had bad fuel put in the car? Or something worse?

Answer
Hi, Char.  Most likely, this issue is transmission-related.  When the transmission control module (TCM) sees an issue that will prevent the transmission from operating properly, it will put the transmission in 3rd gear, typically with a harsh shift, and keep it there until the car is turned off.  It will also at that time request the engine control module (ECM) to turn on the check engine  lamp.  

In order to determine more information about your specific issue, it'll be necessary to read the trouble codes from the ECM and TCM.  Local chain parts stores have advertised that they'll read the codes for free, but some may not have the capability of reading the codes from the TCM.  Accept the code numbers and report them back here in a follow-up, but do not use their diagnostic advice.  In many cases, not only do the parts personnel provide incorrect diagnostic advice, but they also do not understand what the code means.