P2271 fault code: what it means

P2271: Bank 1 rear O2 sensor signal stuck rich.

Engine and gearbox (powertrain) · Minor

Usual causes, most likely first

aged rear O2 sensor
real rich mixture
sensor wiring shorted

P2271 by make

Jeep

Rear O2 sensor (bank 1 sensor 2) stuck rich.

Usual causes: faulty rear O2 sensor; rich running from leaking injector; sensor wiring

What the repair usually costs

Air-fuel ratio / front O2 sensor replace (upstream)NZ$270–NZ$750 · A$260–A$730
O2 sensor replace (downstream / after cat)NZ$180–NZ$480 · A$180–A$460
Direct-injection petrol injectors (set)NZ$1,490–NZ$3,850 · A$1,350–A$3,520

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Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.