AutoCodes – GMC – P11BF 2017 GMC Sierra

P11BF 2017 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 2017 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 192

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 Mar 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P11BF 2017 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 2017 GMC Sierra - O2 Reference Voltage Circuit Low Voltage (NOx Sensor 2) - AutoCodes.com — P11BF 2017 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 2017 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 2017 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 2017 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 2017 GMC Sierra code?

Need more information on how to fix the P11BF 2017 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11BF 2017 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 2017 GMC Sierra Code

1. What are the common symptoms of OBDII code P11BF in a 2017 GMC Sierra related to the O2 reference voltage circuit low voltage (NOx Sensor 2)?

- Common symptoms include poor engine performance, reduced fuel efficiency, illuminated Check Engine light, and potential emission issues.

2. What are the possible causes of OBDII code P11BF in a 2017 GMC Sierra?

- Possible causes include a faulty NOx sensor, damaged wiring or connectors in the O2 reference voltage circuit, a malfunctioning powertrain control module (PCM), or a low battery voltage.

3. How can I diagnose OBDII code P11BF in a 2017 GMC Sierra?

- Diagnosis involves using an OBDII scanner to retrieve the code, checking the NOx sensor and related wiring for damage, inspecting connectors for corrosion, and testing the PCM for proper functionality.

4. What are some repair tips for addressing OBDII code P11BF in a 2017 GMC Sierra?

- Repair tips include replacing the faulty NOx sensor, repairing or replacing damaged wiring and connectors, ensuring proper battery voltage, and reprogramming or replacing the PCM if necessary.

5. Can I drive my 2017 GMC Sierra with OBDII code P11BF related to the O2 reference voltage circuit low voltage (NOx Sensor 2)?

- It is not recommended to drive the vehicle with this code present, as it can lead to further issues and potential damage to the engine or emissions system.

6. How much does it typically cost to repair OBDII code P11BF in a 2017 GMC Sierra?

- The cost of repairs can vary depending on the exact cause of the code, but it may range from $200 to $800 or more, including parts and labor.

7. Is OBDII code P11BF related to the O2 reference voltage circuit low voltage (NOx Sensor 2) a common issue in 2017 GMC Sierra vehicles?

- While not extremely common, this code can occur in 2017 GMC Sierra models due to sensor or circuit issues, and it is important to address it promptly to prevent further problems.

8. Can a DIY enthusiast fix OBDII code P11BF in a 2017 GMC Sierra, or is it best left to professional mechanics?

- Depending on their skill level and access to tools, some DIY enthusiasts may be able to address this code by following proper diagnostic procedures and repair guides. However, complex electrical issues may require professional expertise.

9. Will resetting the Check Engine light clear OBDII code P11BF in a 2017 GMC Sierra?

- Resetting the Check Engine light may temporarily clear the code, but if the underlying issue causing P11BF is not addressed, the code is likely to reappear after driving cycles.

10. How urgent is it to repair OBDII code P11BF in a 2017 GMC Sierra?

- It is recommended to address this code promptly to prevent potential damage to the engine or emissions system, as well as to ensure optimal vehicle performance and fuel efficiency.