A failed or contaminated bank 2 sensor 2 oxygen sensor that is stuck at a high voltage; A wiring fault in the sensor circuit, such as a short to voltage or a chafed harness near the exhaust; An exhaust leak upstream of the sensor that lets outside air in and confuses the reading; A leaking fuel injector on bank 2 that keeps the exhaust genuinely rich at the sensor; High fuel pressure or a faulty fuel pressure regulator causing an overall rich condition; A restricted air intake or dirty mass airflow sensor that skews the base mixture rich; A failing catalytic converter on bank 2 that no longer stores oxygen and lets raw fuel reach the sensor

DTC codes / P22xx · Fuel and air metering (injector circuits) / P2273

P2273O2 Sensor Signal Stuck Rich (Bank 2 Sensor 2)

Q: What does code P2273 mean?

O2 Sensor Signal Stuck Rich (Bank 2 Sensor 2). P2273 means the downstream oxygen sensor on bank 2 is reporting a rich exhaust condition that never changes, so the engine computer cannot see the exhaust lean out as it should during normal fuel control. The computer has detected that the sensor's voltage stays high for longer than expected, indicating a stuck-rich signal rather than a momentary rich mixture.

P2273 means the downstream oxygen sensor on bank 2 is reporting a rich exhaust condition that never changes, so the engine computer cannot see the exhaust lean out as it should during normal fuel control. The computer has detected that the sensor's voltage stays high for longer than expected, indicating a stuck-rich signal rather than a momentary rich mixture.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Often no symptoms besides the warning light, especially if the sensor is lazy rather than failed
A slight drop in fuel economy because the computer may add fuel based on the false rich reading
Rough idle or hesitation when the engine is cold, as fuel trim is skewed by the stuck signal
Black sooty exhaust or a strong fuel smell in severe cases where the sensor is truly stuck rich
Failed emissions inspection because the readiness monitor for the oxygen sensor will not complete

Common causes, most likely first

A failed or contaminated bank 2 sensor 2 oxygen sensor that is stuck at a high voltage
A wiring fault in the sensor circuit, such as a short to voltage or a chafed harness near the exhaust
An exhaust leak upstream of the sensor that lets outside air in and confuses the reading
A leaking fuel injector on bank 2 that keeps the exhaust genuinely rich at the sensor
High fuel pressure or a faulty fuel pressure regulator causing an overall rich condition
A restricted air intake or dirty mass airflow sensor that skews the base mixture rich
A failing catalytic converter on bank 2 that no longer stores oxygen and lets raw fuel reach the sensor

How to diagnose and fix it

Connect a scan tool and read live data for bank 2 sensor 2 voltage and fuel trims to confirm the signal is stuck high
Inspect the sensor wiring and connector for chafing, corrosion, or a short to voltage, and repair as needed
Check for exhaust leaks between the engine and the sensor using a smoke test or by listening for ticking
Test fuel pressure and inspect bank 2 injectors for leakage or a stuck-open condition
Verify intake air flow and clean or replace the mass airflow sensor if readings are out of range
Replace the bank 2 sensor 2 oxygen sensor if the circuit and mixture checks pass but the signal remains stuck
Clear the code and complete a drive cycle to confirm the monitor passes and the code does not return

Why a rich code is not always the sensor

A stuck-rich downstream sensor is frequently caused by a genuine rich mixture from a leaking injector or high fuel pressure, so replacing the sensor first often does not fix the code.
An exhaust leak before the sensor can pull in outside air and make the sensor read lean, but a leak after the sensor can trap rich gas and make it read stuck rich, so leak location matters.
The downstream sensor on bank 2 is often the hardest to reach, and a lazy sensor that responds slowly can set this code without ever failing a simple resistance test.
A failing catalytic converter can store less oxygen over time, causing the downstream sensor to stay rich even when the engine mixture is correct.
Some vehicles set P2273 when the sensor heater circuit is weak, because a cold sensor cannot switch properly and the computer interprets the steady high voltage as stuck rich.

Can I keep driving with P2273?

You can usually drive short distances to a repair shop, but avoid heavy acceleration and long trips because a genuine rich condition can overheat the catalytic converter and waste fuel. If the check engine light starts flashing or you smell raw fuel, stop driving and have it towed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.