AutoCodes – GMC – P11C7 2018 GMC Sierra

P11C7 2018 GMC Sierra Code - NOx Sensor 2 Heater Ground Circuit

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: P11C7 2018 GMC Sierra indicates NOx Sensor 2 Heater Ground Circuit.
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 188

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 P11C7 2018 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 P11C7 2018 GMC Sierra - NOx Sensor 2 Heater Ground Circuit - AutoCodes.com — P11C7 2018 GMC Sierra Code - NOx Sensor 2 Heater Ground Circuit

What does this mean?

What are the Possible Causes of the DTC P11C7 2018 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 P11C7 2018 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 P11C7 2018 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 P11C7 2018 GMC Sierra code?

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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 P11C7 2018 GMC Sierra Code

1. What does the OBDII code P11C7 mean on a 2018 GMC Sierra?

P11C7 indicates an issue with the NOx Sensor 2 Heater Ground Circuit, which monitors and controls the heater for the second NOx sensor in the exhaust system.

2. What are the symptoms of code P11C7 in a 2018 GMC Sierra?

Common symptoms include a check engine light, reduced fuel efficiency, increased emissions, and potentially entering limp mode.

3. What causes the P11C7 code on a 2018 GMC Sierra?

This code is typically caused by a faulty NOx sensor heater, damaged wiring, a poor ground connection, or a malfunctioning Engine Control Module (ECM).

4. Can I drive my 2018 GMC Sierra with a P11C7 code?

While the truck may still be drivable, it is not recommended. Ignoring the issue can lead to higher emissions, poor performance, and potential damage to other exhaust components.

5. How is the P11C7 code diagnosed?

A technician will use a scan tool to verify the code, inspect the NOx sensor wiring and ground connections, test the heater circuit, and potentially check the ECM for faults.

6. What repairs can fix the P11C7 code on a 2018 GMC Sierra?

Repairs may include replacing the NOx sensor, repairing damaged wiring or connectors, cleaning or securing ground connections, or reprogramming or replacing the ECM.

7. How much does it cost to fix the P11C7 code?

The cost can vary but typically ranges from $300 to $800, depending on whether only the NOx sensor or additional components like wiring or the ECM need repairs.

8. Can a bad NOx sensor cause other problems in my 2018 GMC Sierra?

Yes, a malfunctioning NOx sensor can lead to increased emissions, reduced engine performance, and additional strain on the exhaust after-treatment system.

9. What maintenance can prevent P11C7 from occurring?

Regular inspections of the exhaust system, ensuring connections and wiring are secure and undamaged, and addressing check engine lights promptly can help prevent this code.

10. Is an aftermarket NOx sensor a good replacement for the P11C7 issue?

While aftermarket sensors are often cheaper, they may not perform as reliably as OEM parts. Itâ€™s best to use an OEM sensor for compatibility and durability.