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P22A8 2018 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 2018 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 167

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

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 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 P22A8 2018 GMC Sierra - NOx Sensor 2 Heater Feedback Circuit Low Voltage - AutoCodes.com — P22A8 2018 GMC Sierra Code - NOx Sensor 2 Heater Feedback Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A8 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 P22A8 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 P22A8 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 P22A8 2018 GMC Sierra code?

Need more information on how to fix the P22A8 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P22A8 2018 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 2018 GMC Sierra Code

1. What are the common symptoms of OBDII code P22A8 in a 2018 GMC Sierra related to NOx Sensor 2 Heater Feedback Circuit Low Voltage?

- Common symptoms include the illumination of the check engine light, decreased fuel efficiency, and potential issues with the vehicle's emissions system.

2. What can cause the NOx Sensor 2 Heater Feedback Circuit Low Voltage error code (P22A8) in a 2018 GMC Sierra?

- The code can be triggered by a faulty NOx sensor, damaged wiring or connectors, a malfunctioning heater element, or issues with the vehicle's electrical system.

3. How can I diagnose the NOx Sensor 2 Heater Feedback Circuit Low Voltage code (P22A8) in my 2018 GMC Sierra?

- Diagnosis typically involves using an OBDII scanner to read the error code, inspecting the NOx sensor and its connections, and checking the heater circuit for continuity and proper voltage.

4. Can I continue driving my 2018 GMC Sierra with the P22A8 code related to NOx Sensor 2 Heater Feedback Circuit Low Voltage?

- It is not recommended to drive the vehicle with this code present, as it can lead to increased emissions, reduced engine performance, and potential damage to other components.

5. What are some repair tips for addressing the NOx Sensor 2 Heater Feedback Circuit Low Voltage error code (P22A8) in a 2018 GMC Sierra?

- Repair tips may include checking and replacing the NOx sensor, repairing damaged wiring or connectors, testing and replacing the heater element, and ensuring proper electrical connections.

6. Is it possible to reset the OBDII code P22A8 in a 2018 GMC Sierra related to NOx Sensor 2 Heater Feedback Circuit Low Voltage?

- While you can clear the code with an OBDII scanner, it is important to address the underlying issue causing the code to prevent it from reoccurring.

7. How much does it typically cost to repair the NOx Sensor 2 Heater Feedback Circuit Low Voltage issue (P22A8) in a 2018 GMC Sierra?

- The cost of repair can vary depending on the specific cause of the issue, but it may involve expenses for parts, labor, and diagnostic services.

8. Can a DIY enthusiast fix the NOx Sensor 2 Heater Feedback Circuit Low Voltage error code (P22A8) in a 2018 GMC Sierra?

- While some basic troubleshooting and repairs may be possible for experienced DIY enthusiasts, addressing this code often requires specialized tools and expertise, so professional assistance is recommended.

9. Will ignoring the OBDII code P22A8 related to NOx Sensor 2 Heater Feedback Circuit Low Voltage affect the performance of my 2018 GMC Sierra?

- Ignoring this code can lead to decreased fuel efficiency, increased emissions, potential engine performance issues, and may cause further damage to the vehicle's emissions system over time.

10. How long does it typically take to repair the NOx Sensor 2 Heater Feedback Circuit Low Voltage issue (P22A8) in a 2018 GMC Sierra?

- The repair time can vary depending on the exact cause of the code and the complexity of the repair process, but it may range from a few hours to a full day in some cases.