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P11DA 2018 GMC Sierra Code - O2 Pump Current Control Circuit High 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
P11DA 2018 GMC Sierra indicates O2 Pump Current Control Circuit High 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 183
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 P11DA 2018 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 P11DA 2018 GMC Sierra - O2 Pump Current Control Circuit High Voltage (NOx Sensor 2) - AutoCodes.com
P11DA 2018 GMC Sierra Code - O2 Pump Current Control Circuit High Voltage (NOx Sensor 2)
What does this mean?

What are the Possible Causes of the DTC P11DA 2018 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 P11DA 2018 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 P11DA 2018 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 P11DA 2018 GMC Sierra code?

Need more information on how to fix the P11DA 2018 GMC Sierra 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 P11DA 2018 GMC Sierra Code

1. What does OBDII code P11DA mean on a 2018 GMC Sierra?

P11DA indicates an issue with the O2 pump current control circuit for NOx Sensor 2, specifically detecting high voltage, which may affect emissions monitoring.

2. What are the symptoms of P11DA on a 2018 GMC Sierra?

Common symptoms include the check engine light turning on, reduced fuel efficiency, increased emissions, and possible engine performance issues.

3. What causes the P11DA code on a 2018 GMC Sierra?

The code can be caused by a faulty NOx Sensor 2, wiring issues like damaged or corroded connectors, a failing ECM, or electrical faults in the O2 pump current control circuit.

4. Can I drive my 2018 GMC Sierra with a P11DA code?

While it might be safe to drive short distances, prolonged use can lead to increased emissions, potential engine damage, and failure to pass emissions testing.

5. How is the P11DA code diagnosed?

A technician will typically inspect the NOx Sensor 2, check for wiring damage, test the O2 pump circuit voltage, and use a scan tool to monitor sensor data.

6. How do you fix the P11DA code on a 2018 GMC Sierra?

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

7. How much does it cost to fix the P11DA code?

Repair costs can range from $300 to $800, depending on whether the NOx sensor, wiring, or ECM needs replacement.

8. Can a bad NOx Sensor 2 cause other problems in a 2018 GMC Sierra?

Yes, a faulty NOx sensor can lead to incorrect air-fuel mixture adjustments, reduced engine efficiency, and higher emissions.

9. How can I prevent the P11DA code from occurring?

Regular maintenance, inspecting wiring for damage, and using high-quality fuel can help prevent issues with the NOx sensor and related circuits.

10. Do I need to replace both NOx sensors if I have a P11DA code?

No, you typically only need to replace NOx Sensor 2 if it is faulty, but both sensors should be inspected to ensure proper operation.

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