AutoCodes – GMC – P2271 2016 GMC Sierra

P2271 2016 GMC Sierra Code - HO2S Signal Stuck Rich Bank 1 Sensor 2

Quick Answer

The Heated Oxygen Sensors (HO2S) are used for fuel control and catalyst monitoring. Common causes include Faulty Heated Oxygen Bank 1 Sensor 2, Heated Oxygen Bank 1 Sensor 2 harness is open or shorted, Heated Oxygen Bank 1 Sensor 2 circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P2271 2016 GMC Sierra indicates HO2S Signal Stuck Rich Bank 1 Sensor 2.
Common causes: Common causes include Faulty Heated Oxygen Bank 1 Sensor 2, Heated Oxygen Bank 1 Sensor 2 harness is open or shorted, Heated Oxygen Bank 1 Sensor 2 circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 192

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 28, 2022

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code P2271 2016 GMC Sierra Description

The Heated Oxygen Sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the Engine Control Module (ECM) operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0 - 1, 000 mV. Once sufficient HO2S voltage fluctuation is observed by the ECM, Closed Loop is entered. The ECM uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.
The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the ECM to calculate the air-to-fuel ratio sooner.
The Diagnostic Trouble Code (DTC) will be set when the ECM does not detect an HO2S voltage less than 100 mV before accumulated mass airflow exceeds a calibrated value.

OBDII Code P2271 2016 GMC Sierra - HO2S Signal Stuck Rich Bank 1 Sensor 2 - AutoCodes.com — P2271 2016 GMC Sierra Code - HO2S Signal Stuck Rich Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P2271 2016 GMC Sierra?

Faulty Heated Oxygen Bank 1 Sensor 2
Heated Oxygen Bank 1 Sensor 2 harness is open or shorted
Heated Oxygen Bank 1 Sensor 2 circuit poor electrical connection
Low or high fuel system pressure
Fuel contamination
Faulty fuel injectors
Exhaust gas leaks
Engine vacuum leaks

How to Fix the DTC P2271 2016 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

Replacing the Rear Heated Oxygen Sensors (HO2S) usually takes care of the problem.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2271 2016 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P2271 2016 GMC Sierra Code

1. What does the OBDII code P2271 mean on a 2016 GMC Sierra?

P2271 indicates that the downstream oxygen sensor (Bank 1, Sensor 2) is detecting a consistently rich fuel mixture, meaning there is too much fuel and not enough oxygen in the exhaust.

2. What are the common symptoms of code P2271 in a 2016 GMC Sierra?

Symptoms may include a check engine light, poor fuel economy, black smoke from the exhaust, and potentially rough idling or reduced engine performance.

3. What causes the P2271 code to appear on a 2016 GMC Sierra?

Common causes include a faulty downstream oxygen sensor, exhaust leaks, a malfunctioning fuel injector, a rich-running engine, or wiring/connectivity issues with the oxygen sensor.

4. Can I drive my 2016 GMC Sierra with a P2271 code?

While the vehicle may still be drivable, prolonged operation with this code can lead to increased emissions, poor fuel economy, and potential damage to the catalytic converter.

5. How do I fix the P2271 code on my 2016 GMC Sierra?

Repairs may include replacing the downstream oxygen sensor, repairing exhaust leaks, inspecting and repairing wiring, or addressing issues with the fuel system causing a rich condition.

6. How can I diagnose the P2271 code on my 2016 GMC Sierra?

Use an OBDII scanner to confirm the code, inspect the oxygen sensor and its wiring for damage, check for exhaust leaks, and test the fuel system for rich-running conditions.

7. Is the P2271 code specific to the 2016 GMC Sierra?

No, P2271 is a generic OBDII code that can appear on many vehicles, but troubleshooting steps and symptoms may vary depending on the make and model.

8. How much does it cost to fix the P2271 code on a 2016 GMC Sierra?

Costs vary depending on the repair needed. Replacing an oxygen sensor may cost $150-$300, while addressing exhaust or fuel system issues could cost more.

9. Can a dirty air filter cause the P2271 code on a 2016 GMC Sierra?

A dirty air filter is unlikely to directly cause P2271, but it can contribute to a rich-running condition, which might trigger the code. Replacing the air filter is a good maintenance step.

10. Will clearing the P2271 code fix the issue on my 2016 GMC Sierra?

Clearing the code with an OBDII scanner will turn off the check engine light temporarily, but the underlying issue must be addressed to prevent the code from returning.