Having problems with your 2001 Hyundai XG300 ?
The car down shifts on it's own. With out moving your foot.
Most probably the Throttle Position Sensor has gone bad or is going bad. Scan for any trouble codes (DTC's) using an OBD!! scan tool. Your XG uses a drive by wire/sensor system called the ETS - Electronic Throttle System. There is a control module which operates the step-motor connected to the throttle plate. The gas pedal you press is cable connected to a sensor called the APS (Accelerator Position Sensor - which could also be the cause of your 'downshift by itself' issue. Both these sensors are simple potentiometers and can wear out and develop bad spots in the wiper plates/contacts.
Repair Help & Product Troubleshooting for 2001 Hyundai XG300
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