AutoCodes.com
Login with Google
AutoCodes – GMC – P11FE 2015 GMC Sierra

P11FE 2015 GMC Sierra Code - O2 Low Reference Circuit High 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
P11FE 2015 GMC Sierra indicates O2 Low Reference Circuit High 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 140
How popular is this code, among other codes? Low
What is this?
Table of contents Created and updated by William Orellana on Mar 24, 2024
💬 Need more help? Ask Coddy for instant answers — it's free!

Code P11FE 2015 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 P11FE 2015 GMC Sierra - O2 Low Reference Circuit High Voltage (NOx Sensor 2) - AutoCodes.com
P11FE 2015 GMC Sierra Code - O2 Low Reference Circuit High Voltage (NOx Sensor 2)
What does this mean?

What are the Possible Causes of the DTC P11FE 2015 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 P11FE 2015 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 P11FE 2015 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 P11FE 2015 GMC Sierra code?

Need more information on how to fix the P11FE 2015 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11FE 2015 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 P11FE 2015 GMC Sierra Code

1. What does the OBDII code P11FE mean on a 2015 GMC Sierra?

P11FE indicates an issue with the "O2 Low Reference Circuit High Voltage" for NOx Sensor 2, which monitors nitrogen oxide emissions.

2. What are the symptoms of the P11FE code on a 2015 GMC Sierra?

Common symptoms include an illuminated check engine light, reduced fuel efficiency, poor engine performance, or the vehicle entering limp mode.

3. What causes the P11FE code to appear on the 2015 GMC Sierra?

Possible causes include a faulty NOx sensor 2, damaged or corroded wiring, a poor electrical connection, or a malfunction in the engine control module (ECM).

4. How do I diagnose the P11FE code on my GMC Sierra?

Start by scanning for codes, inspecting the wiring and connectors for damage, testing the NOx sensor’s voltage, and verifying the ECM functionality.

5. Can I drive my 2015 GMC Sierra with the P11FE code?

While the truck may still run, driving with this code can lead to further damage, reduced performance, or higher emissions. It’s best to address the issue promptly.

6. How do I fix the P11FE code on a 2015 GMC Sierra?

Repairs may include replacing the NOx sensor 2, repairing damaged wiring or connectors, or reprogramming/updating the ECM if necessary.

7. How much does it cost to repair the P11FE code on a GMC Sierra?

The cost depends on the exact issue but typically ranges from $200 to $600 for parts and labor, with the NOx sensor being the most expensive component.

8. Where is NOx sensor 2 located on a 2015 GMC Sierra?

NOx sensor 2 is typically located downstream in the exhaust system, near the catalytic converter.

9. Can a bad NOx sensor cause the P11FE code?

Yes, a malfunctioning NOx sensor is one of the most common causes of the P11FE code.

10. Does the P11FE code affect emissions testing on a 2015 GMC Sierra?

Yes, the code indicates an emissions-related issue, which will likely cause the vehicle to fail emissions testing until repaired.

Discuss the causes and fixes for P11FE 2015 GMC Sierra OBDII Code

Submit a New Comment

Code P11FE 2015 GMC Sierra comments

No comments found for this page.

AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play