AutoCodes – GMC – P11B3 GMC

P11B3 GMC Code - HO2S Performance During Deceleration Fuel Cut-Off Bank 1 Sensor 2

Quick Answer

The oxygen content of the exhaust is measured via the nitrogen oxide (NOx) sensors. Common causes include Faulty Nitrogen Oxide (NOx) Sensor 2, Nitrogen Oxide Sensor 2 harness is open or shorted, Nitrogen Oxide Sensor 2 circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P11B3 GMC indicates HO2S Performance During Deceleration Fuel Cut-Off Bank 1 Sensor 2.
Common causes: Common causes include Faulty Nitrogen Oxide (NOx) Sensor 2, Nitrogen Oxide Sensor 2 harness is open or shorted, Nitrogen Oxide Sensor 2 circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 658

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 30, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P11B3 GMC Description

The oxygen content of the exhaust is measured via the nitrogen oxide (NOx) sensors. The nitrogen oxides (NOx) sensors are part of the selective catalytic reduction system, a device used to reduce NOx emission on diesel engines. There are two NOx sensors, one placed upstream of selective catalytic reduction, to measure inlet NOx concentration, and one placed downstream. They are connected with the control module via CAN and all the information is exchanged through it. Since it is a smart sensor, all the electrical monitoring is performed inside the sensor and only the results are sent to the ECM. Each NOx sensor contains a sensing cell, a pumping cell, and a heater. A sample of exhaust gas passes through a diffusion gap between the sensing cell and the pumping cell. The NOx sensor maintains a constant reference voltage across the sensing cell. An electronic circuit within sensor controls the pump current through the pumping cell in order to maintain a constant voltage in the sensing cell. The amount of current required to maintain the reference voltage in the sensing cell is proportional to the concentration of NOx in the exhaust. The ECM varies the amount of diesel exhaust fluid (reductant) added by varying the reductant injector duty cycle in response to changes in engine exhaust NOx levels. The smart NOx sensors consist of two components, the NOx module and the NOx sensor element that are serviced as a unit. A circuit or performance condition with a NOx sensor is detected by the NOx sensor module. The smart NOx sensor module communicates the condition to the ECM over the serial data line. The ECM sets a DTC when a serial data message is received from the NOx sensor module. The Diagnostic Trouble Code (DTC) will be set when the NOx sensor module detects a fault in the NOx sensor circuitry or a performance fault in the NOx sensor.

OBDII Code P11B3 GMC - HO2S Performance During Deceleration Fuel Cut-Off Bank 1 Sensor 2 - AutoCodes.com — P11B3 GMC Code - HO2S Performance During Deceleration Fuel Cut-Off Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P11B3 GMC?

Faulty Nitrogen Oxide (NOx) Sensor 2
Nitrogen Oxide Sensor 2 harness is open or shorted
Nitrogen Oxide Sensor 2 circuit poor electrical connection

How to Fix the DTC P11B3 GMC?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P11B3 GMC 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.

Need more information about the P11B3 GMC code?

Need more information on how to fix the P11B3 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11B3 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P11B3 2014 GMC Sierra — HO2S Performance During Deceleration Fuel Cut-Off Bank 1 Sensor 2
P11B3 2015 GMC Sierra — HO2S Performance During Deceleration Fuel Cut-Off Bank 1 Sensor 2
P11B3 2016 GMC Sierra — HO2S Performance During Deceleration Fuel Cut-Off Bank 1 Sensor 2
P11B3 2017 GMC Sierra — HO2S Performance During Deceleration Fuel Cut-Off Bank 1 Sensor 2
P11B3 2018 GMC Sierra — HO2S Performance During Deceleration Fuel Cut-Off Bank 1 Sensor 2

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 P11B3 GMC Code

What does the OBDII code P11B3 mean on a GMC vehicle?

The P11B3 code indicates a performance issue with the downstream oxygen sensor (Bank 1, Sensor 2) during a deceleration fuel cut-off event.

What are the common symptoms of the P11B3 code in a GMC?

Symptoms may include an illuminated check engine light, reduced fuel efficiency, or irregular exhaust emissions.

What causes the P11B3 code to trigger?

Common causes include a faulty downstream oxygen sensor, damaged wiring or connectors, or an exhaust leak near the sensor.

How do I diagnose the P11B3 code on my GMC?

Start by inspecting the wiring and connectors for damage, checking for exhaust leaks, and testing the downstream oxygen sensor for proper operation.

Can a dirty air filter cause the P11B3 code?

While unlikely, a clogged air filter can indirectly affect engine performance and emissions, which may lead to related sensor issues.

Is it safe to drive with the P11B3 code active?

Driving with this code is generally safe, but itâ€™s best to address it promptly to avoid potential damage to the catalytic converter or reduced fuel efficiency.

How do I fix the P11B3 code on a GMC vehicle?

Repairs may include replacing the downstream oxygen sensor, repairing damaged wiring, or fixing exhaust leaks near the sensor.

How much does it cost to fix the P11B3 code?

Repair costs can range from $100 to $300, depending on whether the oxygen sensor or other components need replacement.

Can a software update resolve the P11B3 code?

In some cases, a reprogramming of the engine control module (ECM) may resolve the issue if it's related to incorrect sensor calibration.

What tools are needed to troubleshoot the P11B3 code?

Youâ€™ll typically need an OBDII scanner, a multimeter for testing electrical connections, and possibly tools to inspect or replace the oxygen sensor.