AutoCodes – Buick – P11D2 Buick

P11D2 Buick 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 Buick 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.

Save to My Repairs My Repairs

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

Code Popularity 381

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

What does this mean?

What are the Possible Causes of the DTC P11D2 Buick?

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 Buick?

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 Buick 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 Buick code?

Need more information on how to fix the P11D2 Buick code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11D2 Buick 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 P11D2 Buick Code

1. What are the common symptoms of OBDII code P11D2 (O2 Signal Circuit High Voltage - NOx Sensor 2) in a Buick?

- Common symptoms include a check engine light, reduced engine performance, decreased fuel efficiency, and possible exhaust emissions issues.

2. What are the potential causes of OBDII code P11D2 in a Buick?

- The code P11D2 may be triggered by issues such as a faulty NOx sensor 2, wiring or connector problems, a failed powertrain control module (PCM), or exhaust system leaks.

3. How is O2 signal circuit high voltage (NOx Sensor 2) issue diagnosed in a Buick?

- Diagnosis typically involves using an OBDII scanner to retrieve the specific fault code, conducting a visual inspection of the sensor and related components, and testing the sensor's voltage output.

4. Can driving with OBDII code P11D2 in a Buick cause further damage?

- Continuing to drive with this code may lead to increased emissions, potential damage to the catalytic converter, and a possible decrease in overall engine performance.

5. What are some repair tips for fixing O2 signal circuit high voltage (NOx Sensor 2) issue in a Buick?

- Repair options may include replacing the NOx sensor 2, repairing or replacing damaged wiring and connectors, resetting the PCM, and ensuring proper installation and connection of all components.

6. Is it possible to reset OBDII code P11D2 in a Buick without fixing the underlying issue?

- While clearing the fault code may temporarily turn off the check engine light, the issue causing the code will persist, potentially leading to further problems down the line.

7. Can a DIY enthusiast fix O2 signal circuit high voltage (NOx Sensor 2) issue in a Buick?

- Depending on their skill level and access to tools, a DIY enthusiast may be able to address simpler aspects of the problem, such as checking and replacing fuses, connectors, or wiring.

8. How much does it typically cost to repair OBDII code P11D2 in a Buick?

- The cost of repair can vary widely based on the specific cause of the issue, ranging from a few hundred dollars for sensor replacement to potentially more for complex wiring or PCM repairs.

9. What steps can be taken to prevent O2 signal circuit high voltage (NOx Sensor 2) issue in a Buick?

- Regular maintenance, including checking and replacing sensors as recommended, ensuring proper installation of components, and addressing any engine issues promptly, can help prevent this problem.

10. Is it safe to drive a Buick with the O2 signal circuit high voltage (NOx Sensor 2) issue?

- While the vehicle may still be operable with this issue, it is recommended to address the problem promptly to avoid potential damage to other engine components and ensure optimal performance and fuel efficiency.