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P11D9 2014 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 2014 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 190
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 2014 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 2014 Chevrolet Silverado - O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2) - AutoCodes.com
P11D9 2014 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 2014 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 2014 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 2014 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 2014 Chevrolet Silverado code?

Need more information on how to fix the P11D9 2014 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 2014 Chevrolet Silverado Code

What does the OBDII code P11D9 mean for a 2014 Chevrolet Silverado?

P11D9 indicates a low voltage issue in the O2 pump current control circuit of NOx Sensor 2, which monitors nitrogen oxide levels in the exhaust system.

What are the common symptoms of code P11D9?

Symptoms may include reduced engine performance, decreased fuel efficiency, the check engine light illuminating, and potential difficulty meeting emissions standards.

What causes the P11D9 code to appear in a 2014 Chevrolet Silverado?

Common causes include a faulty NOx Sensor 2, wiring issues such as damaged or corroded connectors, or a malfunctioning sensor control circuit.

Can a bad NOx sensor cause the P11D9 code?

Yes, a faulty NOx Sensor 2 can trigger this code, as it may fail to function correctly or provide inaccurate voltage readings to the O2 pump control circuit.

How can I diagnose the P11D9 code?

Inspect NOx Sensor 2 and its wiring for damage or corrosion, check for loose connectors, and test the sensor circuit voltage using a multimeter.

Is it safe to drive with the P11D9 code active?

While the vehicle may remain drivable, ignoring the code can lead to reduced fuel efficiency, higher emissions, and potential long-term damage to the emission control system.

How do I fix the P11D9 code on a 2014 Silverado?

Repairs may include replacing NOx Sensor 2, repairing or replacing damaged wiring, and ensuring the sensor’s circuit connections are clean and secure.

Can a software update resolve the P11D9 code?

In some cases, a software update for the engine control module (ECM) may be required, but hardware issues like a faulty sensor or wiring are more common causes.

What tools are needed to resolve the P11D9 code?

You may need an OBDII scanner, a multimeter for electrical testing, and basic tools for removing and replacing the sensor or repairing wiring.

Will clearing the code fix the problem permanently?

Clearing the code may temporarily turn off the check engine light, but the underlying issue must be addressed to prevent the code from returning.

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