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P22A8 2015 GMC Sierra Code - NOx Sensor 2 Heater Feedback Circuit Low Voltage

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: P22A8 2015 GMC Sierra indicates NOx Sensor 2 Heater Feedback Circuit Low Voltage.
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 144

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 P22A8 2015 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 P22A8 2015 GMC Sierra - NOx Sensor 2 Heater Feedback Circuit Low Voltage - AutoCodes.com — P22A8 2015 GMC Sierra Code - NOx Sensor 2 Heater Feedback Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A8 2015 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 P22A8 2015 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 P22A8 2015 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 P22A8 2015 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 P22A8 2015 GMC Sierra Code

1. What are common symptoms of OBDII code P22A8 in a 2015 GMC Sierra related to NOx Sensor 2 Heater Feedback Circuit Low Voltage?

Symptoms may include the Check Engine light turning on, reduced engine performance, and potential failure to pass emissions testing.

2. What are possible causes of the NOx Sensor 2 Heater Feedback Circuit Low Voltage fault code in a 2015 GMC Sierra?

Potential causes could be a faulty NOx sensor, damaged wiring or connectors, a blown fuse, or issues with the vehicle's onboard computer.

3. How can I diagnose the NOx Sensor 2 Heater Feedback Circuit Low Voltage issue in my 2015 GMC Sierra?

Diagnosis typically involves using an OBDII scanner to retrieve the specific fault code, visually inspecting sensor wiring and connections, checking for blown fuses, and testing the sensor's resistance.

4. Can I continue driving my 2015 GMC Sierra with the P22A8 code related to NOx Sensor 2 Heater Feedback Circuit Low Voltage?

It is generally not recommended to drive the vehicle with this fault code present, as it may lead to reduced fuel efficiency, engine performance issues, and potential damage to the emission control system.

5. How can I repair the NOx Sensor 2 Heater Feedback Circuit Low Voltage problem in my 2015 GMC Sierra?

Repair options may include replacing the NOx sensor, repairing or replacing damaged wiring or connectors, checking and replacing blown fuses, or resetting the fault code with an OBDII scanner after addressing the underlying issue.

6. Are there any DIY tips for addressing the NOx Sensor 2 Heater Feedback Circuit Low Voltage fault code in a 2015 GMC Sierra?

DIY enthusiasts with automotive experience may attempt to visually inspect wiring and connectors, check and replace fuses, and replace the NOx sensor themselves if comfortable working on vehicle components.

7. How much does it cost to fix the NOx Sensor 2 Heater Feedback Circuit Low Voltage issue in a 2015 GMC Sierra?

The cost of repairs can vary depending on the specific cause of the fault code, but it may range from a few hundred to over a thousand dollars when factoring in parts and labor.

8. Can a faulty NOx Sensor 2 Heater affect the overall performance of my 2015 GMC Sierra?

Yes, a malfunctioning NOx sensor can impact engine performance, fuel efficiency, and emissions control, potentially leading to drivability issues and a decrease in overall vehicle performance.

9. Will resetting the Check Engine light resolve the NOx Sensor 2 Heater Feedback Circuit Low Voltage fault code in my 2015 GMC Sierra?

Resetting the Check Engine light may temporarily clear the fault code, but if the underlying issue causing the code is not addressed, the light is likely to come back on as the vehicle's onboard computer detects the problem again.

10. How often should the NOx sensors be inspected in a 2015 GMC Sierra to prevent issues like the P22A8 fault code?

It is recommended to have the NOx sensors inspected during routine maintenance checks or if you experience symptoms of a faulty sensor. Regular inspections can help catch potential issues early and prevent more serious problems down the line.