AutoCodes – GMC – P11FC 2017 GMC Sierra

P11FC 2017 GMC Sierra Code - O2 Low Reference Circuit (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: P11FC 2017 GMC Sierra indicates O2 Low Reference Circuit (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 198

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
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Code P11FC 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 P11FC 2017 GMC Sierra - O2 Low Reference Circuit (NOx Sensor 2) - AutoCodes.com — P11FC 2017 GMC Sierra Code - O2 Low Reference Circuit (NOx Sensor 2)

What does this mean?

What are the Possible Causes of the DTC P11FC 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 P11FC 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 P11FC 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 P11FC 2017 GMC Sierra code?

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Need Help with the 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 P11FC 2017 GMC Sierra Code

1. What does OBDII code P11FC mean on a 2017 GMC Sierra?

P11FC indicates an issue with the O2 low reference circuit for NOx Sensor 2, which monitors nitrogen oxide levels in the exhaust.

2. What are the symptoms of code P11FC in a 2017 GMC Sierra?

Symptoms may include the check engine light turning on, reduced fuel efficiency, increased emissions, and potential performance issues.

3. What causes code P11FC to appear?

Common causes include a faulty NOx Sensor 2, damaged wiring or connectors in the O2 low reference circuit, or issues with the ECM (engine control module).

4. Can I drive my 2017 GMC Sierra with code P11FC?

Driving with this code is possible but not recommended, as it could lead to increased emissions, reduced performance, and potential damage to other components.

5. How do I diagnose code P11FC in a 2017 GMC Sierra?

Diagnosis involves scanning the vehicle with an OBDII tool, inspecting the wiring and connectors for damage, and testing the NOx Sensor 2 and its circuits.

6. How do I fix code P11FC on a 2017 GMC Sierra?

Repairs may include replacing the NOx Sensor 2, repairing or replacing damaged wiring, or reprogramming or replacing the ECM if necessary.

7. How much does it cost to fix code P11FC on a 2017 GMC Sierra?

Repair costs vary but typically range from $300 to $800, depending on whether the NOx sensor or wiring needs replacement.

8. Is code P11FC covered under warranty for a 2017 GMC Sierra?

If your vehicle is still under the emissions warranty, the repair might be covered. Check with your dealership for confirmation.

9. What tools are needed to troubleshoot code P11FC?

Tools include an OBDII scanner, multimeter for testing wiring, and potentially a NOx sensor-specific diagnostic tool.

10. Can a dirty exhaust system cause code P11FC?

While unlikely, an excessively dirty or clogged exhaust system could contribute to sensor issues, so itâ€™s worth inspecting the exhaust if this code appears.