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


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,395

Rating Summary
4,978
202
50
30
135
4,978
202
50
30
135

Anthony

6 years of experience
18 reviews
Anthony
6 years of experience
Jeep Grand Cherokee - Check Engine Light is on - Carmichael, California
Anthony was great! We are very happy that we chose to go with this company instead of the overpriced and slow service we get from the Jeep dealership. He was on time and did the job just as expected. He identified a couple of other things that need to be done before the problems get worse. We appreciate having a technician give us direct feedback regarding our vehicle, rather than a service advisor (salesperson) that we've had to deal with in the past at the dealership. We'll be booking the addtional services very soon and will definitely request Anthony again now that he is familiar with our vehicle!

Michael

37 years of experience
113 reviews
Michael
37 years of experience
Subaru Forester - Check Engine Light is on - Santa Fe Springs, California
Michael was punctual and courteous. He knows what he’s doing and I would absolutely recommend him to anyone.

Anthony

6 years of experience
18 reviews
Anthony
6 years of experience
BMW 740Li - Check Engine Light is on - Roseville, California
Very helpful in finding out the fault codes in my bmw 740 li. It was simple fix and that the two tube hose just had to be connected and my drive train malfunction went away. This saved me from having to go the an expensive dealership. Anthony has a good attitude about his work.

Breck

19 years of experience
613 reviews
Breck
19 years of experience
Ram 1500 - Check Engine Light is on - Houston, Texas
Breck did a great job working on my truck. Showed up on time, found any issues I had on my truck and explained everything to me so that I understood what was going on. Went above and beyond, definitely will book him for future appointments.


More related articles

P0910 OBD-II Trouble Code: Gate Select Actuator Circuit/Open
P0910 code means there is an issue detected by the ECM within the gate select actuator circuit often due too open circuits.
P0760 OBD-II Trouble Code: Shift Solenoid C Malfunction
P0670 code means there has been an irregularity detected within shift solenoid C often due too hydraulic blockages or low transmission fluid.
P0261 OBD-II Trouble Code: Cylinder 1 Injector Circuit Low
P0261 P0261 code definition Cylinder 1 Injector Circuit Low What the P0261 code means This trouble code indicates that the powertrain control module has detected a lower reference voltage coming from the number 1 cylinder’s fuel injector than what was...

Related questions

I need help with diagnostic trouble codes that suddenly appeared making vehicle almost undriveable.

Firstly, you should have the battery disconnected and the PCM disconnected. Check their connectors for any problems and apply dielectric lube to the connectors so the connection is clean from corrosion. If the problem continues then replace the PCM. All...

My 3 year old water pump is leaking. Is it covered under warranty?

Whether Pep Boys should warranty the water pump or not is only dependent on the warranty details. I can say that most warranties from repair shops are for twelve months and 12,000 miles. You will need to refer to the...

Check engine light spontaneously comes on

Hi there, thanks for writing in about your 2003 Geo Tracker. There are numerous potential causes for the problem you are having. It could be anything from a bad spark plug to a failed sensor. The only way to know...

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