AutoCodes – GMC – P11FE 2017 GMC Sierra

P11FE 2017 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 2017 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.

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Code Popularity 130

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 P11FE 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 P11FE 2017 GMC Sierra - O2 Low Reference Circuit High Voltage (NOx Sensor 2) - AutoCodes.com — P11FE 2017 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 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 P11FE 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 P11FE 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 P11FE 2017 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 P11FE 2017 GMC Sierra Code

1. What does the OBDII code P11FE mean on a 2017 GMC Sierra?

P11FE indicates an issue with the O2 low reference circuit reporting high voltage, specifically related to NOx Sensor 2.

2. What are common symptoms of code P11FE in a 2017 GMC Sierra?

Symptoms may include reduced fuel efficiency, poor engine performance, illuminated check engine light, and potential issues with emissions system operation.

3. What causes the P11FE code to appear?

Possible causes include damaged wiring or connectors in the NOx sensor circuit, a faulty NOx Sensor 2, corrosion in the sensor's electrical connections, or a malfunctioning engine control module (ECM).

4. Can a bad NOx Sensor 2 trigger the P11FE code?

Yes, a failing NOx Sensor 2 is a common cause of this code, as it may send incorrect voltage signals to the ECM.

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

Start by inspecting the wiring and connectors for damage or corrosion, then test the NOx Sensor 2 for proper function using a multimeter or diagnostic tool.

6. Can I drive my 2017 GMC Sierra with the P11FE code?

While the vehicle may still be drivable, it is not recommended as it could lead to reduced performance, increased emissions, and potential damage to other components.

7. How do I fix the P11FE code?

Common repairs include repairing or replacing damaged wiring, cleaning corroded connectors, or replacing the faulty NOx Sensor 2.

8. What tools are needed to troubleshoot the P11FE code?

You may need a multimeter, an OBDII scanner, and basic tools for inspecting and repairing wiring or connectors.

9. How much does it cost to fix the P11FE code on a GMC Sierra?

The repair cost can vary, but replacing a NOx sensor typically ranges from $300 to $700, including parts and labor.

10. Can a software update resolve the P11FE code?

In some cases, a software update for the ECM may address false readings, but this solution is less common and should only be considered after physical repairs have been ruled out.