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P11D9 2015 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 2015 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 212
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 2015 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 2015 Chevrolet Silverado - O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2) - AutoCodes.com
P11D9 2015 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 2015 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 2015 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 2015 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 2015 Chevrolet Silverado code?

Need more information on how to fix the P11D9 2015 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 P11D9 2015 Chevrolet Silverado Code

1. What does the OBDII code P11D9 mean on a 2015 Chevrolet Silverado?

P11D9 indicates an issue with the O2 Pump Current Control Circuit for NOx Sensor 2, specifically a low voltage condition.

2. What are the common symptoms of code P11D9 in a 2015 Chevrolet Silverado?

Symptoms may include a check engine light, reduced fuel efficiency, poor engine performance, and possible emissions test failure.

3. What causes the P11D9 code to appear?

Common causes include a faulty NOx sensor 2, damaged wiring or connectors in the sensor circuit, a failed control module, or a low voltage supply to the sensor.

4. Can I drive my 2015 Silverado with the P11D9 code?

While the vehicle may still be drivable, it’s not recommended as prolonged driving could lead to increased emissions and potential damage to other components.

5. How do I diagnose the P11D9 code?

Start by checking the wiring and connectors for NOx Sensor 2 for damage or corrosion. Use a scan tool to monitor sensor readings and voltage to pinpoint the issue.

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

Repairs may include replacing the NOx sensor 2, repairing or replacing damaged wiring or connectors, or reprogramming/updating the control module if necessary.

7. How much does it cost to repair the P11D9 code?

Repair costs vary but typically range from $200 to $700, depending on whether the NOx sensor or wiring needs to be replaced.

8. Can a bad NOx sensor cause the P11D9 code?

Yes, a malfunctioning NOx sensor 2 is a common cause of this code as it affects the O2 pump current control circuit.

9. How do I prevent the P11D9 code from returning?

Regular maintenance, including inspecting wiring and sensors for damage and ensuring proper voltage supply, can help prevent this code.

10. Is a software update necessary for fixing the P11D9 code?

In some cases, a software update or reprogramming of the control module may be required to resolve compatibility or calibration issues.

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