Question

2009 Nissan Sentra 2.0L changed both sensors and have P1148, P0171, P0031 in error. Why? What can I do?

Answer 1

P1148 Closed loop control

P0171 Fuel trim lean Bank 1

P0031 A/F sensor 1 heater

The part you replace have to be specific for that car according to the VIN, some are California model which require that specification, the other is Federal which is not California specific

Answer 2

P0031 NISSAN - HO2S11 Heater Control Circuit Low
Read more: https://www.autocodes.com/p0031_nissan.html

P0171 NISSAN - Fuel Injection System Too Lean Bank 1
Read more: https://www.autocodes.com/p0171_nissan.html

P1148 NISSAN - Closed Loop Control Function Bank 1
Read more: https://www.autocodes.com/p1148_nissan.html