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DTC code page

P2273: O2 Sensor Signal Stuck Rich (Bank 2 Sensor 2)

Quick answer: The downstream oxygen sensor on Bank 2 is reporting a rich-looking signal that appears stuck or implausibly biased high.

Drivers also search this fault as bank 2 sensor 2 stuck rich, rear O2 stuck rich bank 2, downstream oxygen sensor stuck rich bank 2.

Severity: medium Family: powertrain Related paths: 17
Meaning

What P2273 usually means

P2273 is the Bank 2 rich-side partner to P2272. The ECU sees the Bank 2 downstream oxygen sensor acting stuck rich or strongly biased high. Sometimes that is the downstream shadow of a real rich-running problem on Bank 2. Other times it is a biased rear sensor, catalyst damage after misfire or EVAP flooding, or wiring trouble in the Bank 2 post-catalyst branch. The important thing is that P2273 is not a direct injector verdict by itself.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Look for Bank 2 rich, misfire, EVAP, or catalyst history before isolating P2273 by itself.
  • Check whether the rich-looking story is only downstream or also supported by upstream fuel-trim and O2 data.
  • Inspect the Bank 2 rear sensor connector and exhaust path for damage or contamination.
Driving risk

Can you keep driving?

P2273 often is driveable short-term, but prolonged rich operation or repeated misfire behind it can finish off the Bank 2 catalyst.

Moderate urgency: This code often allows short-term driving, but the right fix usually comes faster when you diagnose it early instead of waiting for more codes.
Likely causes

Common causes behind this code

  • Bank 2 Sensor 2 oxygen sensor biased high or contaminated
  • Catalyst damage or saturation after prolonged rich running or misfire on Bank 2
  • EVAP or rich-running history affecting rear-sensor and catalyst behavior
  • Connector or wiring fault on the Bank 2 downstream sensor path
  • Recent Bank 2 exhaust work creating contamination or installation issues

Cause phrases often tied to this code: rear O2 sensor bias high bank 2, catalyst contamination, rich exhaust history, wiring issue, sensor contamination.

Diagnostic order

Suggested workflow

  1. Verify P2273 is Bank 2 Sensor 2 and review freeze-frame context.
  2. Compare Bank 2 rear behavior with front-sensor and fuel-trim data to see whether the rich condition is real upstream.
  3. Look for P0175, P2099, misfire, or EVAP flooding history that may have affected the catalyst.
  4. Inspect Bank 2 rear-sensor wiring, connector condition, and exhaust-area damage.
  5. Replace the rear sensor only after the signal proves irrational or non-responsive.
Avoid guesswork

Common mistakes

  • Treating P2273 like a guaranteed injector or fuel-pressure problem.
  • Ignoring catalyst and misfire history that may have changed the Bank 2 rear signal.
  • Replacing the converter before proving whether the rear sensor is biased.
Repair path

Practical fix guidance

  • Fix active rich-running, misfire, or EVAP flooding issues first when they are present.
  • Replace Bank 2 Sensor 2 when it is proven contaminated, biased, or electrically unstable.
  • If the rear sensor tests well, evaluate Bank 2 catalyst condition with the rest of the code pattern in mind.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P2273

Useful when the driver knows the wording but not the exact DTC yet.

  • bank 2 sensor 2 stuck rich
  • rear O2 stuck rich bank 2
  • downstream oxygen sensor stuck rich bank 2
Related search intent

Queries this page can answer naturally

  • P2273 code meaning
  • what does P2273 mean
  • bank 2 sensor 2 signal stuck rich
  • rear O2 biased rich bank 2
FAQ

Quick questions about P2273

Is P2273 the Bank 2 version of P2271?

Yes. Both are downstream stuck-rich codes, but on different banks.

Can catalyst damage trigger P2273?

Yes. A contaminated or weak catalyst can change the downstream oxygen-storage pattern enough to make the rear signal look stuck rich.

Does P2273 automatically mean the rear O2 sensor is bad?

No. The rear sensor is only one branch. Upstream rich operation, catalyst condition, and wiring all matter.