AutoCodes – Chevrolet – P11D2 2018 Chevrolet Silverado

P11D2 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado 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 227

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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado - O2 Signal Circuit High Voltage (NOx Sensor 2) - AutoCodes.com — P11D2 2018 Chevrolet Silverado Code - O2 Signal Circuit High Voltage (NOx Sensor 2)

What does this mean?

What are the Possible Causes of the DTC P11D2 2018 Chevrolet Silverado?

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 2018 Chevrolet Silverado?

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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado code?

Need more information on how to fix the P11D2 2018 Chevrolet Silverado code? Get Access to Factory Service Manuals

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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 2018 Chevrolet Silverado Code

- What does OBDII code P11D2 mean on a 2018 Chevrolet Silverado?

P11D2 indicates that the Engine Control Module (ECM) has detected a high voltage issue in the O2 signal circuit of NOx Sensor 2, which monitors nitrogen oxide emissions.

- What are the common symptoms of code P11D2?

Symptoms may include an illuminated Check Engine Light, reduced fuel efficiency, poor engine performance, or the vehicle entering limp mode.

- What causes the P11D2 code to appear?

Possible causes include a faulty NOx Sensor 2, damaged wiring or connectors in the O2 signal circuit, excessive corrosion, or a malfunctioning ECM.

- Can I drive my 2018 Chevrolet Silverado with the P11D2 code?

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

- How do I diagnose the P11D2 code?

Start by inspecting the wiring and connectors for damage or corrosion, then test the NOx Sensor 2 for proper operation using a multimeter or scan tool.

- How is the P11D2 code fixed?

Repairs may include replacing the NOx Sensor 2, repairing or replacing damaged wiring, cleaning corroded connectors, or reprogramming the ECM if needed.

- How much does it cost to repair the P11D2 code?

The cost can range from $200 to $600, depending on whether the issue is with the sensor, wiring, or ECM, and labor rates in your area.

- Can a faulty NOx Sensor 2 cause other problems in my Silverado?

Yes, a faulty sensor can lead to increased emissions, reduced fuel efficiency, and potential damage to the exhaust system components like the catalytic converter.

- Is the P11D2 code covered under warranty for a 2018 Chevrolet Silverado?

It may be covered under the emissions warranty if the vehicle is within the warranty period. Check with your dealership for details.

- How can I prevent the P11D2 code from recurring?

Regular maintenance, keeping the wiring and connectors clean and free of corrosion, and addressing issues promptly can help prevent this code from returning.