AutoCodes – GMC – P22A4 2016 GMC Sierra

P22A4 2016 GMC Sierra Code - NOx Sensor 2 Heater Control 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: P22A4 2016 GMC Sierra indicates NOx Sensor 2 Heater Control 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 147

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 P22A4 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 P22A4 2016 GMC Sierra - NOx Sensor 2 Heater Control Circuit Low Voltage - AutoCodes.com — P22A4 2016 GMC Sierra Code - NOx Sensor 2 Heater Control Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A4 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 P22A4 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 P22A4 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 P22A4 2016 GMC Sierra code?

Need more information on how to fix the P22A4 2016 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 P22A4 2016 GMC Sierra Code

1. What are the common symptoms of OBDII code P22A4 (NOx Sensor 2 Heater Control Circuit Low Voltage) in a 2016 GMC Sierra?

The common symptoms include poor engine performance, decreased fuel efficiency, and the illumination of the Check Engine light on the dashboard.

2. What could be causing the NOx Sensor 2 Heater Control Circuit Low Voltage code in a 2016 GMC Sierra?

Possible causes include a faulty NOx sensor, damaged wiring or connectors in the heater circuit, a blown fuse, or a problem with the vehicle's ECM (Engine Control Module).

3. How can I diagnose the NOx Sensor 2 Heater Control Circuit Low Voltage issue in my 2016 GMC Sierra?

Diagnosing this issue usually involves using an OBDII scanner to retrieve the specific fault code, checking the wiring and connectors for any damage, testing the NOx sensor's heater element, and ensuring proper voltage supply to the sensor.

4. Can I continue driving my 2016 GMC Sierra with the P22A4 code (NOx Sensor 2 Heater Control Circuit Low Voltage) illuminated?

It is not recommended to drive the vehicle with this fault code present, as it can lead to further damage and potential emissions issues. It's best to address the problem promptly.

5. Are there any DIY repair tips for fixing the NOx Sensor 2 Heater Control Circuit Low Voltage error in a 2016 GMC Sierra?

While some basic troubleshooting steps can be taken, repairing this issue often requires specialized tools and knowledge. It is advisable to consult a qualified mechanic or dealership for proper diagnosis and repair.

6. How much does it typically cost to repair the NOx Sensor 2 Heater Control Circuit Low Voltage fault in a 2016 GMC Sierra?

The cost of repair can vary depending on the exact cause of the issue. It may involve replacing the NOx sensor, repairing wiring or connectors, or addressing ECM problems. Costs can range from a few hundred to over a thousand dollars.

7. Can a faulty NOx sensor cause other problems in a 2016 GMC Sierra besides triggering the P22A4 code?

Yes, a malfunctioning NOx sensor can impact the vehicle's emissions control system, overall engine performance, and fuel efficiency. It is essential to address NOx sensor issues promptly to avoid further complications.

8. Is it possible to reset the Check Engine light after fixing the NOx Sensor 2 Heater Control Circuit Low Voltage error in a 2016 GMC Sierra?

Yes, once the underlying issue triggering the fault code has been resolved, the Check Engine light can be reset using an OBDII scanner or by disconnecting the vehicle's battery for a short period.

9. Can extreme weather conditions or driving habits contribute to the occurrence of the P22A4 code (NOx Sensor 2 Heater Control Circuit Low Voltage) in a 2016 GMC Sierra?

Extreme temperatures, harsh driving conditions, or prolonged idling can potentially affect the NOx sensor's performance and heater circuit, leading to the triggering of this fault code.

10. How often should the NOx sensor and related components be inspected in a 2016 GMC Sierra to prevent issues like the P22A4 code (NOx Sensor 2 Heater Control Circuit Low Voltage)?

Regular maintenance schedules, as recommended by the vehicle manufacturer, should include periodic inspections of emissions control components, including the NOx sensor and its heater circuit, to catch any potential issues early and prevent codes like P22A4 from appearing.