AutoCodes – GMC – P11D2 2015 GMC Sierra

P11D2 2015 GMC Sierra Code - O2 Signal Circuit High Voltage (NOx Sensor 2)

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: P11D2 2015 GMC Sierra indicates O2 Signal Circuit High Voltage (NOx Sensor 2).
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 161

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 P11D2 2015 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 P11D2 2015 GMC Sierra - O2 Signal Circuit High Voltage (NOx Sensor 2) - AutoCodes.com — P11D2 2015 GMC Sierra Code - O2 Signal Circuit High Voltage (NOx Sensor 2)

What does this mean?

What are the Possible Causes of the DTC P11D2 2015 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 P11D2 2015 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 P11D2 2015 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 P11D2 2015 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 P11D2 2015 GMC Sierra Code

1. What does the OBDII code P11D2 mean on a 2015 GMC Sierra?

The code P11D2 indicates an "O2 Signal Circuit High Voltage" issue related to NOx Sensor 2, which monitors nitrogen oxide levels in the exhaust system.

2. What are the common symptoms of a P11D2 code?

Symptoms may include the check engine light turning on, reduced engine performance, poor fuel efficiency, and potentially a higher level of emissions.

3. What causes the P11D2 code to appear on a 2015 GMC Sierra?

Common causes include a faulty NOx sensor 2, damaged wiring or connectors in the sensor circuit, or issues with the NOx sensor module.

4. Can a dirty or failing NOx sensor trigger the P11D2 code?

Yes, a dirty or failing NOx sensor can cause incorrect voltage signals, leading to this error code.

5. How do I diagnose the P11D2 code on my GMC Sierra?

Start by scanning the vehicle with an OBDII tool, inspecting the wiring and connectors for damage or corrosion, and testing the NOx sensor with a multimeter to check for proper voltage.

6. Can I continue driving with a P11D2 code on my 2015 GMC Sierra?

Driving with this code is not recommended, as it may affect fuel efficiency, emissions, and engine performance over time.

7. How do I fix the P11D2 code on a 2015 GMC Sierra?

Repairs may include replacing the NOx sensor 2, repairing damaged wiring or connectors, or updating the vehicle's ECM software if necessary.

8. How much does it cost to repair a P11D2 code?

The cost can range from $200 to $600 or more, depending on whether the NOx sensor needs replacement or if additional wiring repairs are required.

9. Can a software update fix the P11D2 code?

In some cases, a software update to the engine control module (ECM) may resolve the issue if it is related to incorrect parameter settings.

10. What happens if the P11D2 code is ignored?

Ignoring this code can lead to increased emissions, reduced fuel economy, and potential damage to the catalytic converter or other exhaust system components.