P2271 OBD-II Trouble Code: O2 Sensor Signal Stuck Rich Bank 1 Sensor 2

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P2271 code

P2271 is a diagnostic trouble code (DTC) for "O2 Sensor Signal Stuck Rich Bank 1 Sensor 2". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P2271 DIAGNOSTIC Get a fair and transparent estimate upfront

P2271 trouble code definition

O2 Sensor Signal Stuck Rich Bank 1 Sensor 2

What the P2271 code means

This code indicates the downstream O2 (oxygen sensor) on bank 1 has failed an onboard test run by the PCM (powertrain control module). Bank 1 is the set of cylinders that includes the number one cylinder.

What causes the P2271 code?

The PCM monitors the sensor data on deceleration and expects to see it indicate a lean condition in a specified amount of time. The time frame for this test is different with every manufacturer. If the O2 fails this test, it is assumed the O2 is faulty.

What are the symptoms of the P2271 code?

The only symptom will be a Check Engine Light. Downstream O2 sensors, as indicated by the sensor 2 position, are used to determine if the catalytic converter is operating efficiently. It will not have any effect on drivability of the vehicle.

How does a mechanic diagnose the P2271 code?

For the most part, this code is fairly foolproof as an indicator of a failure. If there are no other codes, the technician will likely just replace the sensor. The PCM is performing the same test the technician would perform manually, although with a different method.

Although, if the technician has reason to believe there are other circumstances that could set this code, he or she should perform the necessary diagnostics to confirm or prove wrong his concern. These concerns would be out of the ordinary circumstances such as customer working on their own vehicle that could have inadvertently set such a code. This example only serves as one example. All other ideas about concerns would be purely speculation.

Common mistakes when diagnosing the P2271 code

Visually inspecting the exhaust system for leaks, the electrical harness for corrosion or other damage is very important and often forsaken. There are numerous other failures that can set this code, although they usually set their own code or codes. These codes should be diagnosed first. At times, but rarely, an actual rich running condition could exist that could set this code. If a technician were to miss such a condition, the O2 sensor could be replaced and not fix the problem.

Identifying which O2 sensor is which is sometimes cumbersome. Replacing the wrong sensor happens at times. Anytime an O2 sensor is replaced, care should be taken when identifying the correct sensor.

How serious is the P2271 code?

This code is not serious to the drivability of the vehicle for the simple reason that this code is usually only an indicator of a bad downstream O2 sensor. Barring other problems that might contribute to the setting of this code, this code is minor.

What repairs can fix the P2271 code?

  • Replace the bank 1 sensor 2 oxygen sensor
  • Repair O2 the bank 1 sensor 2 wiring harness
  • Replace the O2 connector
  • Fix any exhaust leaks
  • Repairing all other drivability codes and issues first
  • Repair the PCM (Not a common failure)

Additional comments for consideration regarding the P2271 code

All O2 sensors do the same thing, they measure the amount of oxygen in the exhaust stream. The more oxygen there is the leaner the vehicle is running. What’s important about this particular code is recognizing where it is mounted in the exhaust system. When an O2 sensor is labeled a downstream sensor, it means it is mounted after the catalytic converter. If this is the case, it is used for emissions and not for the calculation of the air fuel ratio. The O2 operates the same as an upstream O2, but the data it produces is different.

An upstream O2 will oscillate rapidly between 0.1 volts and 0.9 volts indicating the PCM is making rapid changes to the amount of fuel injected in order to maintain the most efficient conditions for the motor.

A downstream O2 will not oscillate rapidly. It should move very slowly in its voltage range indicating the catalytic converter is successfully reducing the amount of HC’s (hydrocarbons) emitted from the exhaust.

Many newer vehicles use an O2 sensor that uses a wider voltage range of 2.0 to 4.0 volts. These sensors are more accurate and are more accurately called air fuel ratio sensors. Although, they are still referred to as O2 sensors.

Need help with a P2271 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

trouble codes
P2271
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P2271 code.

SCHEDULE P2271 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(6,144)

Rating Summary
5,685
221
51
35
152
5,685
221
51
35
152

Chris

11 years of experience
13 reviews
Chris
11 years of experience
Ford F-150 - Check Engine Light is on - North Salt Lake, Utah
We were having problems with our check engine light, and Chris was exceptionally thorough until he found the problem and could help resolve the situation. We appreciate having someone who cares enough to get the job done right, not just done. We will definitely use Chris' services in the future. Thanks Chris.

Leng

21 years of experience
2 reviews
Leng
21 years of experience
Mazda MPV - Check Engine Light is on - Seattle, Washington
Leng arrived on time and explained the issue that my van is having. I will make a follow up appointment for the fix. Friendly, easy to talk to, and professional - thank you very much!

Okela

13 years of experience
11 reviews
Okela
13 years of experience
Land Rover LR4 - Check Engine Light is on - Brooklyn, New York
Okela was incredible! He is super thorough and took time to walk us through the issues with our LR4. Couldn’t recommend more! Thank you Okela!!

Robert

37 years of experience
188 reviews
Robert
37 years of experience
Land Rover LR2 - Check Engine Light is on - Atlanta, Georgia
Robert arrived on time. Did a diagnostic check quickly. He was friendly, and gave great service. He knows how to work on a Land Rover.


More related articles

P0368 OBD-II Trouble Code: Camshaft Position Sensor "B" Circuit High (Bank 1)
What What the P0368 code means Your powertrain control module (PCM) has detected an incorrect voltage reading or waveform from your vehicle’s camshaft position sensor circuit for camshaft sensor “B” in engine bank one. The camshaft position sensor is a...
P0991 OBD-II Trouble Code: Transmission Fluid Pressure Sensor/Switch E Circuit Intermittent
P0991 means that the PCM has detected a variation in the transmission fluid pressure due to a faulty pressure sensor, or transmission failure
P2455 OBD-II Trouble Code: Diesel Particulate Filter Differential Pressure Sensor Short to Voltage
P2455 P2455 code definition Diesel Particulate Filter Differential Pressure Sensor Short to Voltage What the P2455 code means P2455 is an OBD-II generic code that the engine control module (ECM) has detected the diesel particulate filter differential pressure sensor (DPFPS)...

Related questions

I need to know what the trouble code P19DA means

Hi there. The code P19DA means that the fuel pump is not sending a signal back to the PCM. This is usually caused by a burned motor in the fuel pump or a burned meter wire in the fuel pump...

Car starts and runs perfectly for 3-4 minutes then stalls and won't restart for several hours.

Hi there. From the description you have provided, your vehicle's P0335 code is not being corrected by replacing components. Assuming, the replacement components are correct by application and of OEM (original equipment manufacturer) quality. It could be, the crankshaft reluctor...

Can a exhaust leak trigger service engine light

An exhaust leak can trigger a Check Engine Light due to the fact that depending on the location of the leak, the leak itself is introducing more oxygen into the exhaust gases. As you may know the oxygen sensors which...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com