AutoCodes – Generic – P11DC

P11DC Code - NOx Sensor 2 Current Performance

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: P11DC indicates NOx Sensor 2 Current Performance.
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 36,961

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
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Code P11DC 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 P11DC - NOx Sensor 2 Current Performance - AutoCodes.com — P11DC Code - NOx Sensor 2 Current Performance

What does this mean?

What are the Possible Causes of the DTC P11DC?

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 P11DC?

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 P11DC 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 P11DC code?

Need more information on how to fix the P11DC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11DC code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P11DC Buick — NOx Sensor 2 Current Performance
P11DC Cadillac — NOx Sensor 2 Current Performance
P11DC Chevrolet — NOx Sensor 2 Current Performance
P11DC GMC — NOx Sensor 2 Current Performance

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 P11DC Code

1. What are the common symptoms of OBDII code P11DC (NOx Sensor 2 Current Performance)?

- Common symptoms include reduced fuel efficiency, failed emissions test, rough idling, and illuminated Check Engine Light.

2. What are the possible causes of OBDII code P11DC?

- Possible causes include a faulty NOx sensor, wiring issues, exhaust system leaks, engine misfires, or a malfunctioning catalytic converter.

3. How can I diagnose the underlying issue causing OBDII code P11DC?

- Diagnostic steps may include checking the NOx sensor readings, inspecting the wiring harness for damage, conducting a visual inspection of the exhaust system, and performing a thorough scan with an OBDII scanner.

4. Can I continue driving with OBDII code P11DC present?

- It is generally not recommended to continue driving with this code as it can lead to decreased engine performance and potential damage to the catalytic converter.

5. How can I repair OBDII code P11DC?

- Repair options may include replacing the NOx sensor, repairing or replacing damaged wiring, fixing exhaust leaks, addressing engine misfires, or replacing a faulty catalytic converter.

6. Is it possible to reset OBDII code P11DC without fixing the underlying issue?

- While clearing the code may temporarily turn off the Check Engine Light, the issue causing the code will persist and likely trigger the code again in the future.

7. Can a DIY enthusiast fix OBDII code P11DC at home?

- Depending on the underlying cause, some repairs related to this code may be possible for a DIY enthusiast with the right tools, knowledge, and experience.

8. How much does it typically cost to repair OBDII code P11DC at a mechanic or dealership?

- Repair costs can vary significantly depending on the specific issue causing the code, but they may range from a few hundred to over a thousand dollars, including parts and labor.

9. How long does it usually take to repair OBDII code P11DC?

- The repair time can vary based on the complexity of the issue, but it may take anywhere from a couple of hours to a full day to diagnose and fix the problem.

10. Are there any preventive maintenance tips to avoid OBDII code P11DC in the future?

- Regular maintenance, such as keeping up with scheduled tune-ups, monitoring engine performance, and promptly addressing any warning lights, can help prevent issues that may trigger this OBDII code.