Question 1

What does P0131 mean?

Accepted Answer

P0131 - O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1). Upstream O2 sensor on bank 1 is consistently reading lean.

Question 2

What are the symptoms of P0131?

Accepted Answer

Check engine light, Poor fuel economy, Rough idle, Hesitation

Question 3

What causes P0131?

Accepted Answer

Vacuum leak bank 1, Faulty O2 sensor stuck lean, Exhaust leak before sensor, Low fuel pressure, Dirty fuel injectors

Question 4

How much does it cost to fix P0131?

Accepted Answer

Typical repair cost: $80-$300. If P0171 is also present, fix the lean condition first — the O2 sensor may be reading correctly.

P0131 — O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)

Don't guess — diagnose P0131 the right way