First - you are in "limp-home" mode. On your model If the TCM detects a sensor or solenoid related condition, the TCM sets the transaxle in 3rd gear fail-safe to protect the transaxle and to provide a "limp-home" mode for the customer. If we are talking about the same relay, it shuts this relay off to prevent damage to the transmission.
You need to find out if any DTCs were set for the car or transmission. At quick glance I don't think you need a special scanner for this. Please go to Auto Zone or O'Reilly's and for free they can pull the codes to the car. Most important. Once they check your codes, if they find something and you don't get it fixed and need to get back with us, please make sure you tell us exactly what the code was, number and all. Example, if the code was E0568 O2 Sensor bad. Then make sure you give us all of that. While there for free also they can bring their tester out and check your battery, alternator and starter.
If you don't figure it out once the codes are pulled then please get back with us but make sure you provide all the data for the codes per the instructions above.
Also, you may have a minor recall on the transmission. I have attached the info on Limp Home mode and below that the Recall.
SOURCE: Hyundai Tech Net Times Volume 13 Issue 3 2003
TITLE: Third Gear Fail-Safe
APPLIES TO: The following models are equipped with a new generation transaxle (oil pan on side): 1999-2003 Sonata, 2001-03 Elantra, Santa Fe, XG, 2003 Tiburon.
The following models are equipped with a new generation transaxle (oil pan on side): 1999-2003 Sonata, 2001-03 Elantra, Santa Fe, XG, 2003 Tiburon. With this transaxle, the TCM continuously monitors all the sensors and solenoids on the transaxle when the vehicle is in operation. If the TCM detects a sensor or solenoid related condition, the TCM sets the transaxle in 3rd gear fail-safe to protect the transaxle and to provide a "limp-home" mode for the customer.
The TCM normally supplies 12 volts to the A/T control relay, which energizes the solenoids. If the TCM detects a condition that may prevent the correct operation of the transaxle, it turns off the current to the A/T relay, which cuts power to the solenoids. This causes the underdrive and overdrive clutches to be applied, providing 3rd gear fail-safe. The TCM then sets a DTC.
01 - RECALL BULLETINS
Santa Fe 2001-2002
CAMPAIGN 915 - 2001-02 SANTA FE CORRODED AUTOMATIC TRANSAXLE OIL COOLER TUBE
Sunday, November 2nd, 2008 AT 9:56 AM