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P11BF 2014 GMC Sierra Code - O2 Reference Voltage Circuit Low Voltage (NOx Sensor 2)

Quick Answer

The Nitrogen Oxides (NOx) sensors are part of the selective catalytic reduction system, a device used to reduce NOx emission on diesel engines. Common causes include Faulty Nitrogen Oxides (NOx) Sensor 2, Nitrogen Oxides Sensor 2 harness is open or shorted, Nitrogen Oxides 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: P11BF 2014 GMC Sierra indicates O2 Reference Voltage Circuit Low Voltage (NOx Sensor 2).
Common causes: Common causes include Faulty Nitrogen Oxides (NOx) Sensor 2, Nitrogen Oxides Sensor 2 harness is open or shorted, Nitrogen Oxides 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 157

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Mar 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P11BF 2014 GMC Sierra Description

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 Engine Control Module (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 the 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 if the ECM software detects a fault in the NOx sensor circuitry or a performance fault in the NOx sensor for greater than 2 s.

OBDII Code P11BF 2014 GMC Sierra - O2 Reference Voltage Circuit Low Voltage (NOx Sensor 2) - AutoCodes.com — P11BF 2014 GMC Sierra Code - O2 Reference Voltage Circuit Low Voltage (NOx Sensor 2)

What does this mean?

What are the Possible Causes of the DTC P11BF 2014 GMC Sierra?

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

How to Fix the DTC P11BF 2014 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P11BF 2014 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.

Need more information about the P11BF 2014 GMC Sierra code?

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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 P11BF 2014 GMC Sierra Code

What does the OBDII code P11BF mean on a 2014 GMC Sierra?

P11BF indicates "O2 Reference Voltage Circuit Low Voltage (NOx Sensor 2)," meaning the second NOx sensor is detecting a low reference voltage, often related to emissions monitoring.

What are the symptoms of code P11BF in a 2014 GMC Sierra?

Common symptoms include the Check Engine Light turning on, poor fuel efficiency, reduced engine performance, and possible emissions test failure.

What causes the P11BF code to appear in a 2014 GMC Sierra?

The code can be caused by a faulty NOx sensor, damaged wiring or connectors, a malfunctioning engine control module (ECM), or a low reference voltage issue.

How do I diagnose the P11BF code on my GMC Sierra?

Start by inspecting the NOx sensor and its wiring for damage, use a multimeter to check the reference voltage, and scan for additional related trouble codes.

Can I drive my 2014 GMC Sierra with the P11BF code?

Itâ€™s not recommended to drive for extended periods with this code, as it could affect emissions and engine performance, potentially leading to further damage.

How do I fix the P11BF code on a 2014 GMC Sierra?

Repairs may include replacing the NOx sensor, repairing or replacing damaged wiring, ensuring proper electrical connections, or reprogramming the ECM if necessary.

What tools do I need to troubleshoot the P11BF code?

Youâ€™ll need an OBDII scanner, a digital multimeter, and possibly wiring diagrams for the NOx sensor circuit to properly diagnose the issue.

How much does it cost to repair the P11BF code on a GMC Sierra?

Depending on the cause, costs can range from $200 to $600 or more, with NOx sensor replacement typically being the most expensive repair.

Can a bad NOx sensor cause damage to my engine?

While a bad NOx sensor wonâ€™t directly damage the engine, it can lead to poor performance and increased emissions, which may strain other components over time.

Is the P11BF code covered under warranty for a 2014 GMC Sierra?

If your vehicle is still under an emissions warranty or extended warranty, the NOx sensor or related components might be covered; check with your dealership.