Hyundai Sonata LF: Engine Control System / Accelerator Position Sensor (APS) Description and Operation
Accelerator Position Sensor (APS) is installed on the
accelerator pedal module and detects the rotation angle of the
accelerator pedal. The APS is one of the most important sensors in
engine control system, so it consists of the two sensors which adapt
individual sensor power and ground line. The second sensor monitors the
first sensor and its output voltage is half of the first one. If the
ratio of the sensor 1 and 2 is out of the range (approximately 1/2), the
diagnostic system judges that it is abnormal.

Inspection
1.
Connect the GDS on the Data Link Connector (DLC).
2.
Measure the output voltage of the RPS at idle and various engine speed.
ConditionOutput Voltage (V)Idle Approx...
Other information:
C..
Replacement
1.
Raise the vehicle, and make sure it is securely supported.
2.
Remove the wheel cap (A).
Be careful not to damage to the wheel cap (A) when removing the it.
3.
Remove the front wheel and tire (A) from front hub...