Code P2138 Limp Mode Service Engine Light

[Kate1225]

Hello! So about a month after I bought my 2010 Nissan Sentra I started my car one day ( I have a 6 speed), went to take off and my car wouldn't accelerate. The slip light came on, the VDC off light came on and then the service engine soon light came on. My car had basically gone into limp mode. I turned the car off and restarted it and it drove like normal as if nothing had happened. The code is P2138 Pedal Position Sensor / Throttle Position Sensor D/E Correlation. How do I know which I need or if I really need either at all and it isn't just the wiring? I'm gonna have to take it to the dealer, but I just don't want them to force me to buy parts I don't even need. That is the only code there is. This happens like once a month. Any help would be greatly appreciated.