P2A04

O2 Sensor Circuit Range/Performance Bank 2 Sensor 2

Moderate severity

The rear oxygen sensor on bank 2 shows abnormal behaviour during long-term plausibility evaluation. Often a sign of an aged sensor or weakened catalyst.

Common causes

Sensor aging
One of the most commonly reported causes for this code — check this first.
high
Typical part cost: $130-440
Catalyst aging
A plausible cause — test and verify before replacing parts.
medium
Typical part cost: $130-440
See all causes + fix costs
Create a free Wrenchify account to unlock the rest for P2A04.
Unlock causes
Free forever · No credit card

First things to check

1Confirm the code with a scan tool and check for additional related codes.
2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.

Get the full step-by-step diagnosis

Create a free Wrenchify account to unlock the rest for P2A04.

Unlock diagnosis

Free forever · No credit card

Related codes

See related trouble codes

Create a free Wrenchify account to unlock the rest for P2A04.

Unlock related codes

Free forever · No credit card

Frequently asked questions

What does P2A04 mean?

P2A04 means "O2 Sensor Circuit Range/Performance Bank 2 Sensor 2". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.

What are the most common causes of P2A04?

sensor aging; catalyst aging; sensor element aged beyond calibration window — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.

Can I keep driving with this code?

The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.

Get the full P2A04 diagnosis for your vehicle

Year, make, model + step-by-step repair help — free plan included.

Diagnose P2A04