P2271 O2 Sensor Signal Bias / Stuck Rich Bank 1 Sensor 2

P2271 O2 Sensor Signal Bias / Stuck Rich Bank 1 Sensor 2

OBD-II DTC Datasheet

O2 Sensor Signal Bias / Rich Stuck Bank 1 Sensor 2

What does this mean?

This is a generic transmission code which means it applies to all OBD-II vehicles from 1996 onwards. Car brands may include but are not limited to VW, Honda, Dodge, Hyundai, Ford, GMC, Acura, etc. However, specific troubleshooting steps may differ from vehicle to vehicle.

This Diagnostic Trouble Code (DTC) P2271 applies to the post-catalytic converter O2 (oxygen) sensor on bank # 1, sensor # 2. This post-cat sensor is used to monitor the efficiency of the catalytic converter. The converter's job is to reduce exhaust emissions. This DTC will set when the PCM detects the signal from the O2 sensor as stuck Rich or misaligned Rich.

DTC P2271 refers to the downstream sensor (after the catalytic converter), sensor #2 on bank #1. Bank #1 is the side of the engine that contains cylinder #1. There may be a third sensor on the output, if this is a problem, P2275 is set.

This code basically tells you that the signal given by a specific oyxgen sensor is stuck on a rich mixture (which means too little air in the exhaust).

Typical oxygen sensor O2:

symptoms

Chances are you won't notice any handling issues as this is not sensor # 1. You will notice that the Malfunction Indicator Light (MIL) comes on. However, in some cases, the engine may run intermittently.

Possible reasons

Reasons for this DTC may include:

• Dirty or defective HO2S2 sensor (sensor 2)
• HO2S2 Wiring / Circuit Problem
• Incorrect fuel pressure
• Defective fuel injector
• Leaking engine coolant
• Defective purge solenoid valve
• PCM out of order

Diagnostic and repair procedures

Visually inspect wiring and connectors for corrosion, scuffed / abraded / kinked wires, bent / loose wiring pins, burnt and / or crossed wires. Repair or replace as needed.

Check for exhaust leaks or other problems and repair as necessary.

Using a digital volt ohm meter (DVOM) set to ohms, test the harness connectors for resistance. Compare with manufacturer specifications. Replace or repair as necessary.

If you have access to the advanced scan tool, use it to monitor the sensor reading as seen by the PCM (engine running at normal operating temperature in closed loop mode). The rear heated oxygen sensor (HO2S) usually sees voltage fluctuations between 0 and 1 volt, for this DTC you will probably see the voltage stuck at 1 V. Rotating the engine should cause the sensor voltage to change (react).

The most common fixes for this DTC are an exhaust air leak, a problem with the sensor / wiring wiring, or the sensor itself. If you are replacing your O2 sensor, buy an OEM (brand name) sensor for best results.

If you are removing the HO2S, check for contamination from fuel, engine oil, and coolant.

Other troubleshooting ideas: Use a fuel pressure tester, check the fuel pressure at the Schrader valve on the fuel rail. Compare with manufacturer's specification. Inspect the purge solenoid valve. Inspect the fuel injectors. Inspect the coolant passages for leaks.

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