P0131 Nissan Sentra
O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1) · Powertrain Code · Medium · Repair: Moderate
What is P0131?
Low voltage from the upstream O2 sensor on bank 1, indicating a possible lean condition or sensor failure.
When the Nissan Sentra triggers code P0131 (o2 sensor circuit low voltage (bank 1, sensor 1)), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Nissan Sentra.
This repair is rated moderate, meaning some experience and specialty tools required.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Nissan Sentra.
Common Causes on Nissan Sentra
- Failed upstream air-fuel ratio sensor (Bank 1 Sensor 1)
- Exhaust leak at the exhaust manifold or flex pipe
- Sensor wiring damage from heat or road debris
- Contaminated sensor from burning oil (common on QR25DE)
Symptoms
- Check Engine Light on
- Poor fuel economy
- Rough idle
- Hesitation on acceleration
- Failed emissions test
Notes for Nissan Sentra
Nissan uses air-fuel ratio sensors (not standard O2 sensors) upstream; use NTK or Denso quality replacements.