AutoCodes – GMC – P11C5 2018 GMC Sierra

P11C5 2018 GMC Sierra Code - NOx Sensor 1 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, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor 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: P11C5 2018 GMC Sierra indicates NOx Sensor 1 Heater Ground Circuit.
Common causes: Common causes include Faulty Nitrogen Oxides (NOx) Sensor, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor 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 377

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
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Code P11C5 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 P11C5 2018 GMC Sierra - NOx Sensor 1 Heater Ground Circuit - AutoCodes.com — P11C5 2018 GMC Sierra Code - NOx Sensor 1 Heater Ground Circuit

What does this mean?

What are the Possible Causes of the DTC P11C5 2018 GMC Sierra?

Faulty Nitrogen Oxides (NOx) Sensor
Nitrogen Oxides Sensor harness is open or shorted
Nitrogen Oxides Sensor circuit poor electrical connection

How to Fix the DTC P11C5 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 P11C5 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 P11C5 2018 GMC Sierra code?

Need more information on how to fix the P11C5 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11C5 2018 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 P11C5 2018 GMC Sierra Code

1. What are the common symptoms of OBDII code P11C5 in a 2018 GMC Sierra related to the NOx Sensor 1 Heater Ground Circuit?

The common symptoms include the Check Engine light illuminating on the dashboard, decreased fuel efficiency, and potential engine performance issues.

2. What are the possible causes of OBDII code P11C5 in a 2018 GMC Sierra?

Common causes of this code include a faulty NOx sensor, damaged wiring or connectors in the heater circuit, or issues with the ground connection for the sensor.

3. How can I diagnose the NOx Sensor 1 Heater Ground Circuit issue in my 2018 GMC Sierra?

You can use an OBDII scanner to read the specific code, visually inspect the sensor and its connections for any visible damage, and perform a continuity test to check the wiring for the heater circuit.

4. Can I still drive my 2018 GMC Sierra with the P11C5 code related to the NOx Sensor 1 Heater Ground Circuit?

It is not recommended to drive the vehicle with this code present, as it can lead to increased emissions, potential damage to the engine, and may result in the vehicle failing an emissions test.

5. How can I repair the NOx Sensor 1 Heater Ground Circuit issue in my 2018 GMC Sierra?

Repair options include replacing the faulty NOx sensor, repairing or replacing damaged wiring or connectors, and ensuring a proper ground connection for the sensor.

6. Are there any DIY tips for fixing the OBDII code P11C5 in a 2018 GMC Sierra myself?

While basic visual inspections and continuity tests can be done at home, it is recommended to have a professional diagnose and repair the issue to ensure proper functioning of the NOx sensor and related components.

7. How much does it typically cost to repair the NOx Sensor 1 Heater Ground Circuit issue in a 2018 GMC Sierra?

Costs can vary depending on the exact cause of the problem and labor rates in your area, but expect to pay anywhere from $200 to $500 for parts and labor to address this issue.

8. Can a faulty NOx sensor cause other problems in my 2018 GMC Sierra besides triggering the P11C5 code?

Yes, a faulty NOx sensor can lead to increased emissions, reduced fuel efficiency, and potentially affect the overall performance and emissions compliance of the vehicle.

9. Will resetting the OBDII code P11C5 in my 2018 GMC Sierra make the issue go away?

Simply resetting the code will not fix the underlying problem causing the P11C5 code. It is important to diagnose and repair the root cause to ensure proper functioning of the NOx sensor and related components.

10. How often should the NOx sensor in a 2018 GMC Sierra be inspected or replaced to prevent issues like the P11C5 code?

It is recommended to follow the manufacturer's maintenance schedule for your vehicle, which may include periodic inspections of the NOx sensor and related components to prevent issues like the P11C5 code from occurring.