AutoCodes – GMC – P11D1 2014 GMC Sierra

P11D1 2014 GMC Sierra Code - O2 Signal Circuit Low 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: P11D1 2014 GMC Sierra indicates O2 Signal Circuit Low 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 150

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P11D1 2014 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 P11D1 2014 GMC Sierra - O2 Signal Circuit Low Voltage (NOx Sensor 2) - AutoCodes.com — P11D1 2014 GMC Sierra Code - O2 Signal Circuit Low Voltage (NOx Sensor 2)

What does this mean?

What are the Possible Causes of the DTC P11D1 2014 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 P11D1 2014 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 P11D1 2014 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 P11D1 2014 GMC Sierra code?

Need more information on how to fix the P11D1 2014 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11D1 2014 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 P11D1 2014 GMC Sierra Code

1. What does the OBDII code P11D1 mean on a 2014 GMC Sierra?

P11D1 indicates that the vehicle's Engine Control Module (ECM) has detected a low voltage signal from the oxygen (O2) signal circuit of NOx sensor 2, which monitors nitrogen oxide levels in the exhaust system.

2. What are the common symptoms of code P11D1 in a 2014 GMC Sierra?

Common symptoms include reduced engine performance, decreased fuel efficiency, an illuminated check engine light, and in some cases, excessive exhaust emissions.

3. What causes the P11D1 code to be triggered?

P11D1 can be caused by a faulty NOx sensor 2, damaged wiring or connectors in the O2 signal circuit, excessive soot buildup on the sensor, or issues with the ECM.

4. Can I drive my 2014 GMC Sierra with a P11D1 code?

While the vehicle may still be drivable, ignoring this code can lead to further damage to the emissions system, reduced performance, and failure to pass emissions tests.

5. How do I diagnose the P11D1 code on my GMC Sierra?

Start by scanning the ECM for codes, inspecting the wiring and connectors for damage or corrosion, and testing the NOx sensor 2 for proper operation.

6. How do I fix the P11D1 code on a 2014 GMC Sierra?

Repairs may involve replacing the NOx sensor 2, repairing damaged wiring, cleaning excessive soot buildup, or reprogramming the ECM if necessary.

7. How much does it cost to fix a P11D1 code on a GMC Sierra?

The cost can vary but typically ranges from $200 to $600, depending on whether you're replacing the sensor or addressing wiring issues.

8. Can a dirty NOx sensor cause the P11D1 code?

Yes, excessive soot or debris on the NOx sensor can interfere with its readings and cause the P11D1 code to appear.

9. Do I need to reprogram the ECM after replacing the NOx sensor 2?

In some cases, the ECM may need to be updated or recalibrated to properly communicate with the new sensor. Consult your vehicle's service manual for guidance.

10. What tools are needed to troubleshoot the P11D1 code?

Youâ€™ll need an OBDII scanner, a multimeter for testing voltage, and possibly a wrench or socket set to remove the NOx sensor if replacement is required.