AutoCodes – GMC – P22A4 2014 GMC Sierra

P22A4 2014 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 2014 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 142

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 P22A4 2014 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 2014 GMC Sierra - NOx Sensor 2 Heater Control Circuit Low Voltage - AutoCodes.com — P22A4 2014 GMC Sierra Code - NOx Sensor 2 Heater Control Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A4 2014 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 2014 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 2014 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 2014 GMC Sierra code?

Need more information on how to fix the P22A4 2014 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 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code P22A4 in a 2014 GMC Sierra related to NOx Sensor 2 Heater Control Circuit Low Voltage?

Symptoms may include reduced engine performance, failed emissions testing, and the illumination of the check engine light.

2. What are the possible causes of the NOx Sensor 2 Heater Control Circuit Low Voltage code in a 2014 GMC Sierra?

Potential causes may include a faulty NOx sensor, damaged wiring or connectors, a failed heater control circuit, or issues with the vehicle's powertrain control module.

3. How serious is the P22A4 code related to NOx Sensor 2 Heater Control Circuit Low Voltage in a 2014 GMC Sierra?

While the vehicle may still be operable with this code, it is essential to address it promptly to prevent potential damage to the emissions system and ensure optimal engine performance.

4. Can driving with the NOx Sensor 2 Heater Control Circuit Low Voltage code in a 2014 GMC Sierra cause further damage?

Continued driving with this code may lead to increased emissions, reduced fuel efficiency, and potential long-term damage to the vehicle's catalytic converter and other emissions components.

5. How can I diagnose and repair the NOx Sensor 2 Heater Control Circuit Low Voltage code in my 2014 GMC Sierra?

Diagnosis typically involves checking the sensor's wiring and connections, testing the heater circuit, and inspecting the sensor itself. Repair may involve replacing the sensor, repairing wiring issues, or addressing problems with the heater circuit.

6. Is it possible to reset the check engine light after fixing the NOx Sensor 2 Heater Control Circuit Low Voltage issue in my 2014 GMC Sierra?

After resolving the underlying problem and completing the repair, the check engine light can be reset using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes.

7. How much does it cost to repair the NOx Sensor 2 Heater Control Circuit Low Voltage code in a 2014 GMC Sierra?

The cost of repair can vary depending on the specific issue causing the code, the labor rates of the repair shop, and the price of any necessary replacement parts. It is advisable to obtain quotes from different mechanics or dealerships.

8. Can I drive my 2014 GMC Sierra with the NOx Sensor 2 Heater Control Circuit Low Voltage code until I can get it repaired?

While the vehicle may still be operational with this code, continued driving without addressing the underlying issue can lead to potential emissions problems, reduced fuel efficiency, and other issues. It is recommended to address the problem as soon as possible.

9. Will fixing the NOx Sensor 2 Heater Control Circuit Low Voltage code in my 2014 GMC Sierra improve fuel efficiency?

Addressing the underlying issue causing the code may help restore optimal engine performance and fuel efficiency, especially if the problem was affecting the vehicle's emissions control system.

10. How long does it typically take to repair the NOx Sensor 2 Heater Control Circuit Low Voltage code in a 2014 GMC Sierra?

The repair time can vary depending on the specific cause of the code, the availability of parts, and the workload of the repair shop. In some cases, the repair may be completed in a few hours, while more complex issues may take longer to diagnose and fix.