AutoCodes – GMC – P11C8 2015 GMC Sierra

P11C8 2015 GMC Sierra Code - NOx Sensor 2 Heater Ground Circuit High

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: P11C8 2015 GMC Sierra indicates NOx Sensor 2 Heater Ground Circuit High.
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 218

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 P11C8 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 P11C8 2015 GMC Sierra - NOx Sensor 2 Heater Ground Circuit High - AutoCodes.com — P11C8 2015 GMC Sierra Code - NOx Sensor 2 Heater Ground Circuit High

What does this mean?

What are the Possible Causes of the DTC P11C8 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 P11C8 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 P11C8 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 P11C8 2015 GMC Sierra code?

Need more information on how to fix the P11C8 2015 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11C8 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 P11C8 2015 GMC Sierra Code

1. What does the OBDII code P11C8 mean on a 2015 GMC Sierra?

P11C8 indicates an issue with the NOx Sensor 2 Heater Ground Circuit, specifically that the circuit's voltage is higher than expected.

2. What are the symptoms of code P11C8 on a 2015 GMC Sierra?

Common symptoms include an illuminated check engine light, reduced fuel efficiency, potential limp mode activation, and increased exhaust emissions.

3. What causes the P11C8 code to appear?

This code is typically caused by a damaged NOx sensor 2, faulty wiring or connectors in the heater ground circuit, or a malfunctioning Engine Control Module (ECM).

4. Can I drive my 2015 GMC Sierra with the P11C8 code active?

While the truck may be drivable, prolonged operation can lead to reduced performance and potential damage to the emissions system, so it's best to address the issue promptly.

5. How do I diagnose the P11C8 code on a 2015 GMC Sierra?

Start by inspecting the NOx sensor 2 wiring and connectors for damage. Use a multimeter to check for continuity and proper ground, and test the sensor's heater circuit resistance.

6. How do I fix the P11C8 code on my 2015 GMC Sierra?

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

7. What tools do I need to address the P11C8 code?

You'll need an OBDII scanner, a multimeter for electrical testing, and possibly basic hand tools to replace the sensor or repair wiring.

8. How much does it cost to repair a P11C8 code on a 2015 GMC Sierra?

The cost can range from $300 to $700, depending on whether the NOx sensor needs replacement and if additional wiring repairs are required.

9. Can a bad NOx sensor cause other problems on my 2015 GMC Sierra?

Yes, a malfunctioning NOx sensor can lead to poor fuel economy, higher emissions, and potential damage to other emissions-related components.

10. Is the P11C8 code covered under warranty for my 2015 GMC Sierra?

It depends on the vehicle's mileage and warranty terms. Emissions-related components like the NOx sensor may have extended coverage, so check with your dealer.