AutoCodes – Chevrolet – P11D9 Chevrolet

P11D9 Chevrolet Code - O2 Pump Current Control 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: P11D9 Chevrolet indicates O2 Pump Current Control 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.

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Code Popularity 537

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 P11D9 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 P11D9 Chevrolet - O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2) - AutoCodes.com — P11D9 Chevrolet Code - O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2)

What does this mean?

What are the Possible Causes of the DTC P11D9 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 P11D9 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 P11D9 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 P11D9 Chevrolet code?

Need more information on how to fix the P11D9 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11D9 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

P11D9 2014 Chevrolet Silverado — O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2)
P11D9 2015 Chevrolet Silverado — O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2)
P11D9 2016 Chevrolet Silverado — O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2)
P11D9 2017 Chevrolet Silverado — O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2)
P11D9 2018 Chevrolet Silverado — O2 Pump Current Control Circuit Low 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 P11D9 Chevrolet Code

1. What are common symptoms of OBDII code P11D9 in a Chevrolet related to the O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2)?

The common symptoms include decreased fuel efficiency, rough idling, and the illumination of the check engine light.

2. What are the possible causes of OBDII code P11D9 in a Chevrolet indicating O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2)?

Potential causes include a faulty NOx sensor, damaged wiring or connectors in the circuit, or issues with the O2 pump current control module.

3. How can I diagnose the O2 Pump Current Control Circuit Low Voltage issue in my Chevrolet triggering OBDII code P11D9?

You can use a diagnostic scanner to read the code and conduct a visual inspection of the NOx sensor, wiring, and connectors. Testing the O2 pump current control module may also be necessary.

4. Can I drive my Chevrolet with the OBDII code P11D9 present?

It is not recommended to drive your vehicle with this code active, as it can lead to further damage and potentially affect the vehicle's performance.

5. How can I repair the O2 Pump Current Control Circuit Low Voltage problem in my Chevrolet causing OBDII code P11D9?

Repair options may include replacing the NOx sensor, repairing or replacing damaged wiring or connectors, or addressing any issues with the O2 pump current control module.

6. Will resetting the check engine light resolve the OBDII code P11D9 issue in my Chevrolet?

Resetting the check engine light may temporarily turn it off, but it will not fix the underlying problem causing the code. It is recommended to diagnose and repair the issue to prevent it from reoccurring.

7. How much does it typically cost to repair the O2 Pump Current Control Circuit Low Voltage issue triggering OBDII code P11D9 in a Chevrolet?

The cost of repair can vary depending on the specific cause of the problem, but it may range from a few hundred to a few thousand dollars, including parts and labor.

8. Can a DIY enthusiast fix the O2 Pump Current Control Circuit Low Voltage problem causing OBDII code P11D9 in a Chevrolet?

While some DIY enthusiasts may have the skills to diagnose and repair this issue, it is recommended to consult with a professional mechanic or technician, especially when dealing with sensor and electrical components.

9. How often does the O2 Pump Current Control Circuit Low Voltage issue occur in Chevrolet vehicles and trigger OBDII code P11D9?

This issue can occur in Chevrolet vehicles equipped with the specific NOx sensor and O2 pump control system, but its frequency may vary depending on driving conditions and maintenance history.

10. Can a malfunctioning O2 Pump Current Control Circuit affect the overall performance of a Chevrolet vehicle?

Yes, a malfunctioning O2 Pump Current Control Circuit can impact the vehicle's performance by affecting fuel efficiency, emissions levels, and overall engine operation. It is important to address the issue promptly to avoid further complications.