AutoCodes – GMC – P11C5 GMC

P11C5 GMC 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 GMC 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 630

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 29, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P11C5 GMC 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 GMC - NOx Sensor 1 Heater Ground Circuit - AutoCodes.com — P11C5 GMC Code - NOx Sensor 1 Heater Ground Circuit

What does this mean?

What are the Possible Causes of the DTC P11C5 GMC?

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 GMC?

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 GMC 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 GMC code?

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

Need Help with the Code?

Get the P11C5 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P11C5 2014 GMC Sierra — NOx Sensor 1 Heater Ground Circuit
P11C5 2015 GMC Sierra — NOx Sensor 1 Heater Ground Circuit
P11C5 2016 GMC Sierra — NOx Sensor 1 Heater Ground Circuit
P11C5 2017 GMC Sierra — NOx Sensor 1 Heater Ground Circuit
P11C5 2018 GMC Sierra — NOx Sensor 1 Heater Ground Circuit

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 GMC Code

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

- Common symptoms include reduced engine performance, decreased fuel efficiency, and the illumination of the check engine light.

2. What are the possible causes of OBDII code P11C5 GMC indicating an issue with the NOx Sensor 1 Heater Ground Circuit?

- Possible causes may include a faulty NOx sensor, damaged wiring or connectors in the heater circuit, or a malfunctioning engine control module (ECM).

3. How can I diagnose the root cause of OBDII code P11C5 GMC affecting the NOx Sensor 1 Heater Ground Circuit?

- Diagnosis typically involves using a scan tool to retrieve the trouble codes and performing a visual inspection of the sensor, wiring, and connectors. Testing the NOx sensor's heater resistance can also help pinpoint the issue.

4. Can I continue driving my vehicle with OBDII code P11C5 GMC related to the NOx Sensor 1 Heater Ground Circuit?

- It is not recommended to continue driving the vehicle with this code present, as it can lead to further damage and potential emissions issues. It is best to address the problem promptly.

5. What are some repair tips for resolving OBDII code P11C5 GMC associated with the NOx Sensor 1 Heater Ground Circuit?

- Repair tips may include replacing the faulty NOx sensor, repairing any damaged wiring or connectors, and resetting the ECM after completing the repairs.

6. Is it possible to reset OBDII code P11C5 GMC without repairing the underlying issue with the NOx Sensor 1 Heater Ground Circuit?

- While clearing the trouble code temporarily may turn off the check engine light, the underlying issue will persist, and the code is likely to return. It is essential to address the root cause of the problem.

7. Can a DIY enthusiast repair OBDII code P11C5 GMC related to the NOx Sensor 1 Heater Ground Circuit?

- Depending on the individual's skill level and access to tools, repairing this code may be possible for a DIY enthusiast. However, it is recommended to have a professional diagnose and repair complex electrical issues.

8. How much does it typically cost to repair OBDII code P11C5 GMC involving the NOx Sensor 1 Heater Ground Circuit?

- The cost of repair can vary depending on the specific issue causing the code, the labor rates in your area, and whether OEM or aftermarket parts are used. It is advisable to consult a mechanic for an accurate estimate.

9. Will fixing OBDII code P11C5 GMC affecting the NOx Sensor 1 Heater Ground Circuit improve my vehicle's performance and fuel efficiency?

- Addressing this code and resolving the underlying issue can lead to improved engine performance, better fuel efficiency, and overall smoother operation of the vehicle.

10. How often should I have the NOx sensors in my vehicle checked to prevent issues like OBDII code P11C5 GMC from occurring?

- It is recommended to follow the manufacturer's maintenance schedule for inspecting and replacing NOx sensors, typically every 60,000 to 100,000 miles or as specified in the owner's manual. Regular maintenance can help prevent issues with the sensors.