AutoCodes – GMC – P11CC 2018 GMC Sierra

P11CC 2018 GMC Sierra Code - Nox Sensor 1 Performance Signal Low

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: P11CC 2018 GMC Sierra indicates Nox Sensor 1 Performance Signal Low.
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 335

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 P11CC 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 P11CC 2018 GMC Sierra - Nox Sensor 1 Performance Signal Low - AutoCodes.com — P11CC 2018 GMC Sierra Code - Nox Sensor 1 Performance Signal Low

What does this mean?

What are the Possible Causes of the DTC P11CC 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 P11CC 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 P11CC 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 P11CC 2018 GMC Sierra 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 P11CC 2018 GMC Sierra Code

1. What does the P11CC code mean on a 2018 GMC Sierra?

The P11CC code indicates "NOx Sensor 1 Performance Signal Low," which means the upstream NOx sensor is reporting a signal below the expected range or not functioning properly.

2. What are the symptoms of the P11CC code on a GMC Sierra?

Common symptoms include reduced engine performance, poor fuel efficiency, a check engine light, and possibly increased exhaust emissions.

3. What causes the P11CC code to appear?

The code is typically caused by a faulty upstream NOx sensor, wiring issues like damaged or corroded connections, or a problem with the diesel exhaust fluid (DEF) system.

4. Can a dirty DEF system trigger the P11CC code?

Yes, if the DEF injector or system is clogged or contaminated, it can affect NOx sensor performance and trigger the code.

5. How do you diagnose the P11CC code on a 2018 GMC Sierra?

Diagnosis involves scanning for additional codes, inspecting the NOx sensor wiring and connections, testing the sensor's output, and checking the DEF system for proper operation.

6. Is it safe to drive with a P11CC code on a GMC Sierra?

Driving with this code is not recommended as it may lead to decreased performance, higher emissions, and potential damage to the emissions system.

7. How do you fix the P11CC code on a 2018 GMC Sierra?

Repairs may include replacing the upstream NOx sensor, repairing wiring or connection issues, cleaning the DEF system, or reprogramming the engine control module (ECM) if necessary.

8. How much does it cost to repair a P11CC code on a GMC Sierra?

The cost varies but typically ranges from $300 to $800, depending on whether the NOx sensor needs replacement or if additional repairs are required.

9. Can a software update fix the P11CC code on a GMC Sierra?

In some cases, a software update for the ECM may resolve the issue if the problem is software-related rather than hardware.

10. How can I prevent the P11CC code from recurring?

Regular maintenance of the DEF system, using high-quality DEF fluid, and ensuring proper sensor connections can help prevent this code from reappearing.