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P11D2 Chevrolet 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 Chevrolet 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 633

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

What does this mean?

What are the Possible Causes of the DTC P11D2 Chevrolet?

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 Chevrolet?

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 Chevrolet 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 Chevrolet code?

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

Need Help with the Code?

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Information for Specific Chevrolet Models

P11D2 2014 Chevrolet Silverado — O2 Signal Circuit High Voltage (NOx Sensor 2)
P11D2 2015 Chevrolet Silverado — O2 Signal Circuit High Voltage (NOx Sensor 2)
P11D2 2016 Chevrolet Silverado — O2 Signal Circuit High Voltage (NOx Sensor 2)
P11D2 2017 Chevrolet Silverado — O2 Signal Circuit High Voltage (NOx Sensor 2)
P11D2 2018 Chevrolet Silverado — O2 Signal Circuit High Voltage (NOx Sensor 2)

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 Chevrolet Code

What does the OBDII code P11D2 mean for my Chevrolet?

The code P11D2 indicates that there is a high voltage signal in the O2 sensor circuit, specifically for the NOx sensor 2. This may affect the vehicle's emissions control system.

What are the common symptoms of the P11D2 code?

Common symptoms include increased emissions, poor fuel economy, rough engine performance, and the check engine light being illuminated.

What could cause the P11D2 code to trigger?

Possible causes include a faulty NOx sensor, damaged wiring or connectors in the O2 signal circuit, or issues with the engine control module (ECM).

How can I diagnose the P11D2 code?

To diagnose the P11D2 code, check the wiring and connectors for damage, test the NOx sensor for proper function using a multimeter, and inspect for any related codes that may provide additional context.

Can I drive my Chevrolet with the P11D2 code?

While it may be safe to drive for a short period, itâ€™s advisable to get the issue resolved promptly, as it can lead to increased emissions and potential damage to other engine components.

What repairs might be necessary for the P11D2 code?

Repairs may involve replacing the NOx sensor, repairing any damaged wiring, or addressing issues with the ECM if it is found to be malfunctioning.

Is it possible to reset the P11D2 code after repairs?

Yes, after addressing the underlying issue, you can reset the code using an OBDII scanner. However, ensure that the problem is fixed to prevent the code from returning.

How much does it typically cost to fix the P11D2 code?

The cost can vary widely depending on the specific repairs needed, but replacing a NOx sensor typically ranges from $100 to $300, including parts and labor.

Will clearing the P11D2 code resolve the problem permanently?

No, simply clearing the code will not resolve the underlying issue. The root cause must be identified and repaired to prevent the code from reappearing.