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P11D9 2014 GMC Sierra 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 GMC Sierra 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 159

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 2014 GMC Sierra 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 GMC Sierra - O2 Pump Current Control Circuit Low Voltage (NOx Sensor 2) - AutoCodes.com — P11D9 2014 GMC Sierra 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 GMC Sierra?

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 GMC Sierra?

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 GMC Sierra 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 GMC Sierra 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 GMC Sierra Code

1. What does the OBDII code P11D9 mean on a 2014 GMC Sierra?

P11D9 indicates an issue with the O2 pump current control circuit for NOx Sensor 2, specifically a low voltage condition.

2. What are the symptoms of the P11D9 code on a 2014 GMC Sierra?

Common symptoms include the check engine light turning on, reduced fuel efficiency, and potential performance issues such as reduced power or erratic shifting.

3. What causes the P11D9 code on a 2014 GMC Sierra?

This code is typically caused by a faulty NOx sensor, wiring issues such as corrosion or damage, or problems with the engine control module (ECM).

4. Can I drive with the P11D9 code on my 2014 GMC Sierra?

While the vehicle may still be drivable, ignoring the code could lead to reduced engine performance and potential damage to the emissions system over time.

5. How do I diagnose the P11D9 code on my 2014 GMC Sierra?

Diagnosis involves checking the NOx sensor 2 and its wiring for damage, testing the circuit for proper voltage, and verifying the ECM is functioning correctly.

6. How do I fix the P11D9 code on my 2014 GMC Sierra?

Repairs may include replacing the faulty NOx sensor, repairing or replacing damaged wiring, or reprogramming or replacing the ECM if necessary.

7. How much does it cost to fix the P11D9 code on a 2014 GMC Sierra?

The cost varies depending on the repair, but replacing the NOx sensor typically costs between $300 and $600, including parts and labor.

8. Can a bad NOx sensor cause the P11D9 code on my 2014 GMC Sierra?

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

9. What tools are needed to diagnose the P11D9 code on a 2014 GMC Sierra?

Youâ€™ll need an OBDII scanner, a multimeter to test the circuit, and possibly a wiring diagram for the NOx sensor system.

10. Is the P11D9 code covered under warranty for a 2014 GMC Sierra?

It may be covered under the emissions system warranty, which typically lasts longer than the general powertrain warranty. Check with your dealership for details.