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P22FA 2018 Chevrolet Silverado Code - NOx Sensor 1 Performance Slow Response High To Low

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, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor 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
P22FA 2018 Chevrolet Silverado indicates NOx Sensor 1 Performance Slow Response High To Low.
Common causes
Common causes include Faulty Nitrogen Oxides (NOx) Sensor, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor 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 241
How popular is this code, among other codes? Low
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Table of contents Created and updated by William Orellana on Mar 24, 2024
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Code P22FA 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 P22FA 2018 Chevrolet Silverado - NOx Sensor 1 Performance Slow Response High To Low - AutoCodes.com
P22FA 2018 Chevrolet Silverado Code - NOx Sensor 1 Performance Slow Response High To Low
What does this mean?

What are the Possible Causes of the DTC P22FA 2018 Chevrolet Silverado?

  • Faulty Nitrogen Oxides (NOx) Sensor
  • Nitrogen Oxides Sensor harness is open or shorted
  • Nitrogen Oxides Sensor circuit poor electrical connection

How to Fix the DTC P22FA 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 P22FA 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 P22FA 2018 Chevrolet Silverado code?

Need more information on how to fix the P22FA 2018 Chevrolet Silverado 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 P22FA 2018 Chevrolet Silverado Code

1. What does the OBDII code P22FA mean on a 2018 Chevrolet Silverado?

P22FA indicates a performance issue with NOx Sensor 1, specifically a slow response when switching from high to low NOx levels.

2. What are the common symptoms of the P22FA code?

Symptoms may include reduced fuel efficiency, lack of engine power, illuminated check engine light, or increased emissions.

3. What causes the P22FA code on a 2018 Chevrolet Silverado?

Common causes include a faulty NOx sensor 1, sensor wiring issues, soot buildup on the sensor, or a malfunctioning exhaust system.

4. Can I drive my 2018 Chevrolet Silverado with the P22FA code?

Driving with this code is possible but not recommended, as it may lead to increased emissions, poor performance, or potential damage to the exhaust system.

5. How do I fix the P22FA code on my Silverado?

Repairs may include cleaning or replacing the NOx sensor, inspecting and repairing wiring or connectors, or addressing exhaust system issues.

6. How much does it cost to fix a P22FA code on a 2018 Silverado?

Replacing a NOx sensor typically costs between $300 and $800, depending on labor rates and parts pricing.

7. How can I prevent the P22FA code from returning?

Regular maintenance of the exhaust system, using high-quality fuel, and keeping the DEF system in good condition can help prevent this issue.

8. Can a bad NOx sensor damage my engine?

While a bad NOx sensor may not directly damage the engine, it can lead to increased emissions and performance issues if not addressed.

9. What tools are needed to diagnose a P22FA code?

A scan tool capable of reading live data and an ohmmeter to check sensor wiring and resistance are typically required.

10. Is the P22FA code covered under warranty for a 2018 Chevrolet Silverado?

It may be covered under the emissions warranty if the vehicle is within the mileage and time limits. Check with your dealer for specifics.

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