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P11D9 2017 Chevrolet Silverado 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 2017 Chevrolet Silverado 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 221
How popular is this code, among other codes? Low
What is this?
Table of contents Created and updated by William Orellana on Mar 24, 2024
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Code P11D9 2017 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 P11D9 2017 Chevrolet Silverado - O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2) - AutoCodes.com
P11D9 2017 Chevrolet Silverado Code - O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2)
What does this mean?

What are the Possible Causes of the DTC P11D9 2017 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 P11D9 2017 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 P11D9 2017 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 P11D9 2017 Chevrolet Silverado code?

Need more information on how to fix the P11D9 2017 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P11D9 2017 Chevrolet Silverado 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 P11D9 2017 Chevrolet Silverado Code

1. What does the OBDII code P11D9 mean on a 2017 Chevrolet Silverado?

The P11D9 code indicates "O2 Pump Current Control Circuit Low Voltage" for NOx Sensor 2, meaning there is an issue with the voltage signal in the oxygen pump circuit of the second nitrogen oxide sensor.

2. What are the common symptoms of the P11D9 code in a 2017 Silverado?

Symptoms may include reduced engine performance, poor fuel economy, increased emissions, and the check engine light being illuminated.

3. What causes the P11D9 code to appear on a 2017 Chevrolet Silverado?

Common causes include a faulty NOx sensor 2, damaged wiring or connectors, corrosion in the circuit, or issues with the engine control module (ECM).

4. How can I diagnose the P11D9 code on my Silverado?

Diagnose the code by inspecting the wiring and connectors for damage or corrosion, testing the NOx sensor 2 for proper operation, and using a scan tool to monitor the O2 pump circuit voltage.

5. Can driving with the P11D9 code damage my Silverado?

Driving with this code may lead to increased emissions and long-term damage to the engine or exhaust system if left unresolved.

6. How do I fix the P11D9 code on my 2017 Silverado?

Repairs may include replacing NOx sensor 2, repairing or replacing damaged wiring or connectors, and updating or reprogramming the ECM if necessary.

7. How much does it cost to repair the P11D9 code on a 2017 Chevrolet Silverado?

Repair costs vary but typically range from $200 to $600, depending on whether the NOx sensor or wiring needs replacement.

8. Can I clear the P11D9 code without fixing the problem?

Clearing the code without addressing the root cause will temporarily remove the warning but the code will likely reappear.

9. What tools are needed to fix the P11D9 code on a Silverado?

You will need a scan tool, multimeter, and basic automotive tools to diagnose and repair the issue.

10. Is the P11D9 code covered under warranty for a 2017 Chevrolet Silverado?

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

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