AutoCodes – GMC – P11C8 2016 GMC Sierra

P11C8 2016 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 2016 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.

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Code Popularity 135

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 P11C8 2016 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 2016 GMC Sierra - NOx Sensor 2 Heater Ground Circuit High - AutoCodes.com — P11C8 2016 GMC Sierra Code - NOx Sensor 2 Heater Ground Circuit High

What does this mean?

What are the Possible Causes of the DTC P11C8 2016 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 2016 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 2016 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 2016 GMC Sierra code?

Need more information on how to fix the P11C8 2016 GMC Sierra code? Get Access to Factory Service Manuals

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 P11C8 2016 GMC Sierra Code

1. What does the OBDII code P11C8 mean on a 2016 GMC Sierra?

P11C8 indicates an issue with the NOx Sensor 2 Heater Ground Circuit being high, meaning the heater circuit for the second NOx sensor is not functioning properly.

2. What are the symptoms of a P11C8 code on a 2016 GMC Sierra?

Symptoms include an illuminated check engine light, reduced fuel efficiency, potential limp mode activation, and increased emissions output.

3. What causes the P11C8 code to trigger?

Common causes include a faulty NOx sensor 2, damaged wiring or connectors in the sensor circuit, a blown fuse, or issues with the ECM.

4. Can I drive my 2016 GMC Sierra with a P11C8 code?

While the vehicle may still be drivable, itâ€™s not recommended for extended periods as it can lead to increased emissions and potential damage to the emissions system.

5. How do you diagnose a P11C8 code?

Diagnosis involves visually inspecting the wiring and connectors, checking the sensorâ€™s ground circuit, testing the heater resistance, and verifying the ECMâ€™s output.

6. What repairs fix the P11C8 code on a 2016 GMC Sierra?

Repairs may include replacing the NOx sensor 2, repairing damaged wiring, replacing a blown fuse, or reprogramming the ECM if necessary.

7. How much does it cost to repair a P11C8 code?

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

8. Can a faulty NOx sensor cause long-term damage?

Yes, a faulty NOx sensor can lead to increased emissions, reduced engine performance, and potential damage to the catalytic converter over time.

9. How can I prevent the P11C8 code from occurring again?

Regular maintenance, inspecting the wiring harness for damage, and addressing check engine lights promptly can help prevent this issue.

10. Is the P11C8 code covered under warranty for a 2016 GMC Sierra?

It may be covered under the emissions warranty, depending on the vehicleâ€™s mileage and age. Check with your dealership or refer to your warranty documentation.