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AutoCodes – Chevrolet – P11C8 2018 Chevrolet Silverado

P11C8 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado 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 244
How popular is this code, among other codes? Low
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Table of contents Created and updated by William Orellana on Mar 24, 2024
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Code P11C8 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado - NOx Sensor 2 Heater Ground Circuit High - AutoCodes.com
P11C8 2018 Chevrolet Silverado Code - NOx Sensor 2 Heater Ground Circuit High
What does this mean?

What are the Possible Causes of the DTC P11C8 2018 Chevrolet Silverado?

  • 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 2018 Chevrolet Silverado?

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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado code?

Need more information on how to fix the P11C8 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado Code

1. What does the OBDII code P11C8 mean on a 2018 Chevrolet Silverado?

P11C8 indicates an issue with the NOx Sensor 2 Heater Ground Circuit being too high, which may affect emissions monitoring.

2. What are the symptoms of code P11C8 in a Chevy Silverado?

Symptoms may include the check engine light turning on, reduced fuel efficiency, possible limp mode activation, or failed emissions tests.

3. What causes the P11C8 code to appear?

Common causes include a faulty NOx sensor, damaged wiring or connectors in the NOx sensor heater circuit, or a failing engine control module (ECM).

4. Can I drive my 2018 Silverado with a P11C8 code?

While the truck may still drive, ignoring the code can lead to increased emissions and possible engine performance issues over time.

5. How do I diagnose a P11C8 code on my Silverado?

Diagnose by inspecting the NOx sensor wiring and connections for damage, testing the sensor heater circuit, and checking for proper grounding.

6. How do I fix the P11C8 code on a 2018 Chevrolet Silverado?

Repairs may involve replacing the NOx sensor, repairing damaged wiring or connectors, or addressing ECM issues if necessary.

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

The repair cost varies but typically ranges from $300 to $900, depending on whether the sensor or wiring needs replacement.

8. Can a bad NOx sensor cause other problems with my Silverado?

Yes, a faulty NOx sensor can lead to inefficient emissions control, reduced fuel economy, and potential damage to other exhaust components.

9. Will clearing the P11C8 code with a scanner fix the problem?

Clearing the code will not fix the underlying issue; proper diagnosis and repair are necessary to prevent the code from returning.

10. Is the P11C8 code covered under warranty for a 2018 Silverado?

It may be covered under the emissions warranty, depending on the vehicle's mileage and specific warranty terms. Check with your dealer for details.

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