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P22A4 2017 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 2017 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 2017 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 2017 GMC Sierra - NOx Sensor 2 Heater Control Circuit Low Voltage - AutoCodes.com — P22A4 2017 GMC Sierra Code - NOx Sensor 2 Heater Control Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A4 2017 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 2017 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 2017 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 2017 GMC Sierra code?

Need more information on how to fix the P22A4 2017 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P22A4 2017 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 P22A4 2017 GMC Sierra Code

1. What are the common symptoms of OBDII code P22A4 in a 2017 GMC Sierra related to NOx Sensor 2 Heater Control Circuit Low Voltage?

- Common symptoms include poor engine performance, decreased fuel efficiency, and the illumination of the check engine light.

2. What could be the possible causes of OBDII code P22A4 in a 2017 GMC Sierra?

- Possible causes may include a faulty NOx sensor, damaged wiring or connectors, a malfunctioning heater control circuit, or issues with the vehicle's engine control module (ECM).

3. How serious is the NOx Sensor 2 Heater Control Circuit Low Voltage issue in a 2017 GMC Sierra?

- While the issue may not cause immediate harm to the vehicle, it can lead to increased emissions and reduced engine efficiency if left unresolved.

4. Can I continue driving my 2017 GMC Sierra with the P22A4 code related to NOx Sensor 2 Heater Control Circuit Low Voltage?

- It is generally not recommended to drive the vehicle with this code present, as it can affect engine performance and emissions. It's best to address the issue promptly.

5. How can I diagnose and repair OBDII code P22A4 in my 2017 GMC Sierra?

- Diagnosis typically involves checking the NOx sensor, inspecting wiring connections, testing the heater control circuit, and scanning the ECM for related faults. Repairs may involve sensor replacement, wiring repairs, or ECM reprogramming.

6. Is it possible to reset the check engine light after fixing the NOx Sensor 2 Heater Control Circuit Low Voltage issue in a 2017 GMC Sierra?

- Yes, once the underlying issue is resolved, the check engine light can be reset using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes.

7. Are there any preventive maintenance tips to avoid encountering OBDII code P22A4 in a 2017 GMC Sierra?

- Regularly servicing the vehicle, checking for wiring damage, and using high-quality fuel can help prevent issues related to the NOx sensor and heater control circuit.

8. How long does it typically take to repair OBDII code P22A4 related to NOx Sensor 2 Heater Control Circuit Low Voltage in a 2017 GMC Sierra?

- The repair time can vary depending on the exact cause of the issue, but it may take anywhere from 1-3 hours for diagnosis and repair by a qualified technician.

9. Can a DIY enthusiast fix the NOx Sensor 2 Heater Control Circuit Low Voltage problem in a 2017 GMC Sierra?

- While some basic troubleshooting like checking connections can be done by DIY enthusiasts, diagnosing and repairing complex issues related to the NOx sensor and heater control circuit is best left to professional mechanics.

10. Will ignoring OBDII code P22A4 related to NOx Sensor 2 Heater Control Circuit Low Voltage affect the emissions testing of my 2017 GMC Sierra?

- Ignoring the issue can lead to increased emissions, potentially causing your vehicle to fail emissions testing. It's advisable to address the problem before undergoing emissions testing.