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P22A3 2018 Chevrolet Silverado Code - NOx Sensor 2 Heater Control Circuit

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: P22A3 2018 Chevrolet Silverado indicates NOx Sensor 2 Heater Control Circuit.
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 239

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 P22A3 2018 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 P22A3 2018 Chevrolet Silverado - NOx Sensor 2 Heater Control Circuit - AutoCodes.com — P22A3 2018 Chevrolet Silverado Code - NOx Sensor 2 Heater Control Circuit

What does this mean?

What are the Possible Causes of the DTC P22A3 2018 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 P22A3 2018 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 P22A3 2018 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 P22A3 2018 Chevrolet Silverado code?

Need more information on how to fix the P22A3 2018 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P22A3 2018 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 P22A3 2018 Chevrolet Silverado Code

1. What does the OBDII code P22A3 mean on a 2018 Chevrolet Silverado?

P22A3 indicates an issue with the NOx Sensor 2 Heater Control Circuit, which monitors the efficiency of the exhaust system's NOx reduction.

2. What are the symptoms of the P22A3 code in a 2018 Chevrolet Silverado?

Common symptoms include an illuminated check engine light, reduced fuel efficiency, potential limp mode activation, and higher tailpipe emissions.

3. What causes the P22A3 code to appear?

The code can be caused by a faulty NOx sensor, a damaged heater element in the sensor, wiring issues such as corroded or broken connections, or a malfunctioning Engine Control Module (ECM).

4. Can I drive my 2018 Chevrolet Silverado with the P22A3 code?

While it may still be drivable, ignoring the code could lead to reduced fuel efficiency, higher emissions, and potential damage to other exhaust components.

5. How do I diagnose the P22A3 code on my Silverado?

Diagnosis involves using an OBDII scanner to confirm the code, visually inspecting wiring and connectors, testing the NOx sensor heater circuit for proper resistance, and checking for voltage at the sensor.

6. How do I fix the P22A3 code on a 2018 Chevrolet Silverado?

Repairs may include replacing the NOx sensor, repairing damaged wiring or connectors, or reprogramming or replacing the ECM if necessary.

7. How much does it cost to fix the P22A3 code on a Chevrolet Silverado?

The cost can vary, but replacing a NOx sensor typically ranges between $300 and $600, while wiring repairs or ECM replacements may cost more depending on labor and parts.

8. What is the role of NOx Sensor 2 in the exhaust system?

NOx Sensor 2 monitors nitrogen oxide levels in the exhaust gas after the selective catalytic reduction (SCR) system to ensure emissions compliance.

9. Can a bad NOx sensor cause other problems in the vehicle?

Yes, a bad NOx sensor can lead to poor engine performance, reduced fuel economy, and potential damage to the catalytic converter or other emissions components.

10. How can I prevent the P22A3 code from occurring again?

Routine maintenance, including inspecting sensors and wiring for damage, using high-quality fuel, and addressing exhaust system issues promptly, can help prevent recurrence.