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P22A4 2017 Chevrolet Silverado 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 Chevrolet Silverado 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 198

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

What does this mean?

What are the Possible Causes of the DTC P22A4 2017 Chevrolet Silverado?

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 Chevrolet Silverado?

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 Chevrolet Silverado 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 Chevrolet Silverado code?

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

Need Help with the Code?

Get the P22A4 2017 Chevrolet Silverado 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 Chevrolet Silverado Code

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

- Common symptoms include poor fuel efficiency, failed emissions test, rough idling, and illuminated Check Engine Light.

2. What are the possible causes of the NOx Sensor 2 Heater Control Circuit Low Voltage issue in a 2017 Chevrolet Silverado?

- The issue can be caused by a faulty NOx sensor, damaged wiring or connectors, a blown fuse, or issues with the engine control module.

3. How serious is the P22A4 OBDII code related to NOx Sensor 2 Heater Control Circuit Low Voltage in a 2017 Chevrolet Silverado?

- While the vehicle may still be operable with this code, it can lead to reduced fuel efficiency and increased emissions, potentially causing environmental harm.

4. Can I continue driving my 2017 Chevrolet Silverado with the NOx Sensor 2 Heater Control Circuit Low Voltage issue?

- It is generally not recommended to drive the vehicle for an extended period with this issue, as it can lead to long-term damage and increased emissions.

5. How can I diagnose and repair the P22A4 code related to NOx Sensor 2 Heater Control Circuit Low Voltage in my 2017 Chevrolet Silverado?

- Diagnosis typically involves checking the sensor, wiring, connectors, and fuses for damage. Repair may involve replacing the sensor, repairing wiring, or resetting the engine control module.

6. Will resetting the Check Engine Light resolve the NOx Sensor 2 Heater Control Circuit issue in a 2017 Chevrolet Silverado?

- Simply resetting the Check Engine Light may temporarily clear the code, but the underlying issue causing the code will likely persist and trigger the light again.

7. How much does it cost to repair the NOx Sensor 2 Heater Control Circuit Low Voltage issue in a 2017 Chevrolet Silverado?

- The cost of repair can vary depending on the specific cause of the issue, but it may range from a few hundred to over a thousand dollars including parts and labor.

8. Can a DIY enthusiast with basic mechanical skills fix the NOx Sensor 2 Heater Control Circuit Low Voltage problem in a 2017 Chevrolet Silverado?

- While some basic troubleshooting steps can be done by a DIY enthusiast, diagnosing and repairing the root cause of the issue may require specialized tools and knowledge best handled by a professional mechanic.

9. How often does the NOx Sensor 2 Heater Control Circuit Low Voltage issue occur in a 2017 Chevrolet Silverado?

- The occurrence of this specific issue can vary, but it is not uncommon in vehicles with higher mileage or those exposed to harsh driving conditions.

10. Is it necessary to replace the NOx sensor when dealing with the P22A4 code in a 2017 Chevrolet Silverado?

- In many cases, replacing the NOx sensor is the most effective solution to resolve the NOx Sensor 2 Heater Control Circuit Low Voltage issue in a 2017 Chevrolet Silverado.