AutoCodes – GMC – P11C0 2015 GMC Sierra

P11C0 2015 GMC Sierra Code - O2 Reference Voltage 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: P11C0 2015 GMC Sierra indicates O2 Reference Voltage 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 243

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 P11C0 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 P11C0 2015 GMC Sierra - O2 Reference Voltage Circuit High Voltage (NOx Sensor 2) - AutoCodes.com — P11C0 2015 GMC Sierra Code - O2 Reference Voltage Circuit High Voltage (NOx Sensor 2)

What does this mean?

What are the Possible Causes of the DTC P11C0 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 P11C0 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 P11C0 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.

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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 P11C0 2015 GMC Sierra Code

1. What does the OBDII code P11C0 mean on a 2015 GMC Sierra?

The code P11C0 indicates an issue with the O2 reference voltage circuit, specifically a high voltage reading for NOx Sensor 2.

2. What are the common symptoms of code P11C0 on a 2015 GMC Sierra?

Symptoms may include reduced engine performance, increased emissions, poor fuel economy, and the illumination of the check engine light.

3. What causes the P11C0 code to appear on a GMC Sierra?

Common causes include a faulty NOx sensor 2, damaged wiring or connectors in the O2 reference voltage circuit, or a malfunctioning engine control module (ECM).

4. Can a dirty or clogged NOx sensor cause the P11C0 code?

Yes, a dirty or clogged NOx sensor can disrupt its operation and cause issues with the reference voltage circuit.

5. How do I diagnose the P11C0 code on my GMC Sierra?

Start by inspecting the wiring and connectors for damage, check the NOx sensor 2 for proper operation, and use a scan tool to monitor live data from the sensor.

6. Is it safe to drive with the P11C0 code on a 2015 GMC Sierra?

While it may be safe to drive short-term, ignoring the code can lead to increased emissions and potential damage to the exhaust system or engine components.

7. How do I fix the P11C0 code on a GMC Sierra?

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

8. Can a software update for the ECM resolve the P11C0 code?

In some cases, a software update for the ECM may resolve the issue if the problem is related to incorrect sensor calibration or programming.

9. How much does it cost to repair the P11C0 code on a 2015 GMC Sierra?

Repair costs can range from $200 to $600 or more, depending on whether the NOx sensor needs replacement or if additional wiring repairs are required.

10. Can a bad battery or alternator cause the P11C0 code?

While unlikely, a weak battery or alternator can cause electrical issues that may indirectly impact the sensor circuit, so it's worth checking if other electrical problems are present.