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P11D8 2016 GMC Sierra Code - O2 Pump Current Control Circuit (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: P11D8 2016 GMC Sierra indicates O2 Pump Current Control Circuit (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 133

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 P11D8 2016 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 P11D8 2016 GMC Sierra - O2 Pump Current Control Circuit (NOx Sensor 2) - AutoCodes.com — P11D8 2016 GMC Sierra Code - O2 Pump Current Control Circuit (NOx Sensor 2)

What does this mean?

What are the Possible Causes of the DTC P11D8 2016 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 P11D8 2016 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 P11D8 2016 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 P11D8 2016 GMC Sierra code?

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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 P11D8 2016 GMC Sierra Code

1. What does the OBDII code P11D8 mean on a 2016 GMC Sierra?

The P11D8 code indicates an issue with the O2 Pump Current Control Circuit for NOx Sensor 2, which monitors and controls nitrogen oxide emissions.

2. What are the common symptoms of the P11D8 code?

Symptoms may include an illuminated Check Engine Light, poor fuel efficiency, reduced engine performance, or failure to pass an emissions test.

3. What causes the P11D8 code to appear?

Common causes include a faulty NOx sensor, damaged wiring or connectors in the O2 pump current circuit, or an issue with the engine control module (ECM).

4. How can I diagnose the P11D8 code?

Diagnosis involves using an OBDII scanner to confirm the code, inspecting the wiring and connectors for damage, and testing the functionality of the NOx sensor.

5. Can I drive my 2016 GMC Sierra with the P11D8 code?

Driving with the P11D8 code is not recommended, as it can lead to increased emissions, reduced fuel economy, and possible engine damage over time.

6. How do I fix the P11D8 code on my GMC Sierra?

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

7. How much does it cost to fix the P11D8 code?

Costs can vary, but replacing a NOx sensor typically ranges from $300 to $600, including parts and labor. Wiring repairs or ECM replacement could add to the cost.

8. Can a dirty or clogged exhaust system cause the P11D8 code?

Yes, a restricted exhaust system can potentially affect NOx sensor operation and lead to this code.

9. How do I prevent the P11D8 code from coming back?

Regular maintenance, including checking and repairing wiring, using quality fuel, and ensuring your exhaust system is in good condition, can help prevent recurrence.

10. Does the P11D8 code always mean the NOx sensor is bad?

No, while a faulty NOx sensor is a common cause, the issue could also stem from wiring problems, a poor connection, or a malfunctioning ECM.