AutoCodes – GMC – P11D5 2018 GMC Sierra

P11D5 2018 GMC Sierra Code - NOx Sensor 2 Exceeded Minimum Learning Limit

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: P11D5 2018 GMC Sierra indicates NOx Sensor 2 Exceeded Minimum Learning Limit.
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 209

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 P11D5 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 P11D5 2018 GMC Sierra - NOx Sensor 2 Exceeded Minimum Learning Limit - AutoCodes.com — P11D5 2018 GMC Sierra Code - NOx Sensor 2 Exceeded Minimum Learning Limit

What does this mean?

What are the Possible Causes of the DTC P11D5 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 P11D5 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 P11D5 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 P11D5 2018 GMC Sierra code?

Need more information on how to fix the P11D5 2018 GMC Sierra 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 P11D5 2018 GMC Sierra Code

1. What does the OBDII code P11D5 mean on a 2018 GMC Sierra?

P11D5 indicates that NOx Sensor 2 has exceeded its minimum learning limit, meaning the sensor is not functioning within the expected parameters for monitoring nitrogen oxide levels in the exhaust.

2. What are the symptoms of code P11D5 in a 2018 GMC Sierra?

Common symptoms include a check engine light, reduced engine performance, increased fuel consumption, and possible activation of the vehicle's limp mode.

3. What causes code P11D5 to trigger on a 2018 GMC Sierra?

The most common causes are a faulty NOx Sensor 2, wiring or connector issues, excessive soot buildup, or a problem with the selective catalytic reduction (SCR) system.

4. Can a dirty diesel exhaust fluid (DEF) system cause code P11D5?

Yes, contaminated or low-quality DEF can lead to improper NOx sensor readings and trigger this code.

5. How do you diagnose the P11D5 code on a 2018 GMC Sierra?

Diagnosis involves scanning for codes with an OBDII scanner, inspecting the NOx sensor and its wiring for damage, testing the sensor's output, and checking the DEF system for contamination.

6. Can you drive with a P11D5 code on a 2018 GMC Sierra?

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

7. How is the P11D5 code fixed on a 2018 GMC Sierra?

Repairs may include replacing the faulty NOx Sensor 2, cleaning or replacing DEF, repairing wiring issues, or updating the vehicle's engine control module (ECM software).

8. How much does it cost to fix a P11D5 code on a 2018 GMC Sierra?

The cost can vary, but replacing a NOx sensor typically ranges from $300 to $700, depending on parts and labor.

9. Can a software update resolve the P11D5 code on a 2018 GMC Sierra?

In some cases, a software update for the ECM may resolve the issue if the problem is related to inaccurate sensor calibration or logic errors.

10. How can I prevent the P11D5 code from appearing again?

To prevent this code, use high-quality DEF, maintain the SCR system, ensure regular servicing, and address any exhaust-related issues as soon as they arise.