AutoCodes – GMC – P22A4 2015 GMC Sierra

P22A4 2015 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 2015 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 127

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 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 P22A4 2015 GMC Sierra - NOx Sensor 2 Heater Control Circuit Low Voltage - AutoCodes.com — P22A4 2015 GMC Sierra Code - NOx Sensor 2 Heater Control Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A4 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 P22A4 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 P22A4 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 P22A4 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 P22A4 2015 GMC Sierra Code

1. What are the common symptoms of OBDII code P22A4 in a 2015 GMC Sierra related to the NOx Sensor 2 Heater Control Circuit Low Voltage?

The common symptoms include the check engine light coming on, reduced engine performance, and potential failure to pass emissions tests.

2. What could cause the NOx Sensor 2 Heater Control Circuit Low Voltage issue in a 2015 GMC Sierra?

Possible causes may include 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 Control Circuit Low Voltage problem in my 2015 GMC Sierra?

Diagnosis typically involves using an OBDII scanner to read the trouble code, checking the sensor's wiring and connectors for damage, and testing the sensor's heater control circuit for proper voltage.

4. Can I continue driving my 2015 GMC Sierra with the P22A4 code related to the NOx Sensor 2 Heater Control Circuit Low Voltage?

It is generally not recommended to continue driving the vehicle with this issue, as it can lead to decreased fuel efficiency, increased emissions, and potential damage to other components.

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

Repair options may include replacing the faulty NOx sensor, repairing or replacing damaged wiring or connectors, testing and replacing the heater element if necessary, and clearing the trouble code with an OBDII scanner.

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

While some simple checks like inspecting wiring connections can be done by DIY enthusiasts, it is recommended to seek professional help for accurate diagnosis and repair of this complex issue.

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

The cost of repair can vary depending on the exact cause of the issue, the need for parts replacement, and labor charges. It is advisable to get quotes from reputable auto repair shops.

8. What happens if I ignore the OBDII code P22A4 related to the NOx Sensor 2 Heater Control Circuit Low Voltage in my 2015 GMC Sierra?

Ignoring this code can lead to increased emissions, decreased engine efficiency, potential damage to other emission control components, and may cause the vehicle to fail emissions tests.

9. Is the NOx Sensor 2 Heater Control Circuit Low Voltage issue a common problem in 2015 GMC Sierra vehicles?

While not extremely common, issues related to the NOx sensor and heater control circuit can occur in 2015 GMC Sierra models, especially as the vehicle ages.

10. Can resetting the check engine light resolve the P22A4 code in a 2015 GMC Sierra with a NOx Sensor 2 Heater Control Circuit Low Voltage problem?

Simply clearing the check engine light without addressing the underlying issue will not fix the problem. It is important to diagnose and repair the root cause to prevent further complications.