could I be getting the p1148 or p1031 code from having a broken gas cap?

Question

And how much should it cost to get fixed?

Answer 1

No, the broken gas cap will not cause the P1031 or P1148 codes. The P1031 code is for the Air Fuel Ration Sensor, a bad sensor could cause both codes. The price of the sensor varies from shop to shop and if you use aftermarket or factory parts. Also, before replacing any parts, make sure there are no intake or exhaust air leaks.

P1031 NISSAN - Air Fuel Ratio Sensor 1 Heater Control Circuit Low Bank 1

Read more: https://www.autocodes.com/p1031_nissan.html

P1148 NISSAN - Closed Loop Control Function Bank 1

Read more: https://www.autocodes.com/p1148_nissan.html