AutoCodes – GMC – P11D1 2016 GMC Sierra

P11D1 2016 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 2016 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 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)

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 2016 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 2016 GMC Sierra - O2 Signal Circuit Low Voltage (NOx Sensor 2) - AutoCodes.com — P11D1 2016 GMC Sierra Code - O2 Signal Circuit Low Voltage (NOx Sensor 2)

What does this mean?

What are the Possible Causes of the DTC P11D1 2016 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 2016 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 2016 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 2016 GMC Sierra code?

Need more information on how to fix the P11D1 2016 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11D1 2016 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 2016 GMC Sierra Code

What does OBDII code P11D1 mean for a 2016 GMC Sierra?

Code P11D1 indicates that the ECM has detected a low voltage signal in the O2 signal circuit of NOx Sensor 2, which monitors nitrogen oxide emissions.

What are the symptoms of code P11D1 in a 2016 GMC Sierra?

Symptoms may include the check engine light turning on, reduced engine performance, increased emissions, and poor fuel economy.

What causes code P11D1 to appear?

Possible causes include a faulty NOx Sensor 2, damaged wiring or connectors in the O2 signal circuit, or an issue with the ECM.

Can I drive my 2016 GMC Sierra with code P11D1 active?

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

How is code P11D1 diagnosed?

A mechanic will use an OBDII scanner to confirm the code, inspect wiring and connectors for damage, test the NOx Sensor 2, and check the ECM for faults.

What is NOx Sensor 2, and why is it important?

NOx Sensor 2 measures nitrogen oxide levels in the exhaust to help the ECM manage emissions. A malfunction can impact emissions control and engine performance.

How do you fix code P11D1 on a 2016 GMC Sierra?

Repairs may involve replacing the NOx Sensor 2, repairing or replacing damaged wiring, or reprogramming/updating the ECM if necessary.

How much does it cost to repair code P11D1?

Repair costs vary, but replacing a NOx sensor can range from $400 to $800, depending on parts and labor. Wiring or ECM repairs may add to the cost.

Can a dirty exhaust system cause code P11D1?

While unlikely, excessive soot or contamination in the exhaust system can impact sensor performance and should be checked if other fixes fail.

How can I prevent code P11D1 from returning?

Regular maintenance, including inspecting wiring and connectors and using high-quality fuel, can help prevent issues with the NOx sensor and related circuits.