AutoCodes – Generic – P22FA

P22FA 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 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 9,668

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 29, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P22FA 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 - NOx Sensor 1 Performance Slow Response High To Low - AutoCodes.com — P22FA Code - NOx Sensor 1 Performance Slow Response High To Low

What does this mean?

What are the Possible Causes of the DTC P22FA?

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?

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 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 code?

Need more information on how to fix the P22FA code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P22FA code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P22FA Buick — NOx Sensor 1 Performance Slow Response High To Low
P22FA Cadillac — NOx Sensor 1 Performance Slow Response High To Low
P22FA Chevrolet — NOx Sensor 1 Performance Slow Response High To Low
P22FA GMC — NOx Sensor 1 Performance Slow Response High To Low

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 Code

1. What are the common symptoms of OBDII code P22FA (NOx Sensor 1 Performance Slow Response High To Low)?

The common symptoms include decreased fuel efficiency, rough idling, and the illumination of the check engine light.

2. What are the potential causes of the P22FA trouble code?

Possible causes include a faulty NOx sensor, issues with the wiring or connectors related to the sensor, or problems with the exhaust system.

3. How serious is the P22FA code and is it safe to continue driving with this issue?

While the vehicle may still be drivable with this code, it is recommended to address it promptly to prevent further damage to the engine or emissions system.

4. How can I diagnose the P22FA code related to NOx sensor 1 performance?

Diagnosis typically involves using an OBDII scanner to read the code, checking the NOx sensor's readings, inspecting the wiring and connectors, and conducting a visual inspection of the exhaust system.

5. Can I reset the P22FA code by disconnecting the battery, or does it require a professional scan tool?

While disconnecting the battery may temporarily reset the code, it is best to use a professional scan tool to properly diagnose and address the underlying issue causing the code.

6. What are some tips for repairing the P22FA code related to NOx sensor 1 performance slow response high to low?

Repair tips may include replacing the NOx sensor, repairing or replacing any damaged wiring or connectors, ensuring proper exhaust system function, and clearing the code using a scan tool.

7. How much does it cost to repair the P22FA NOx sensor 1 performance slow response high to low code?

The cost of repair can vary depending on the specific issue causing the code, the labor rates in your area, and the cost of parts needed for the repair.

8. Can a DIY enthusiast with basic automotive knowledge fix the P22FA code themselves?

Depending on the underlying cause, a DIY enthusiast with some automotive knowledge may be able to address the P22FA code by following repair guides and using the necessary tools.

9. Are there any recalls or technical service bulletins related to the P22FA NOx sensor 1 performance slow response high to low code?

It's recommended to check with the vehicle manufacturer or authorized service centers for any recalls or technical service bulletins related to this specific OBDII code.

10. How often should the NOx sensors be inspected or replaced to prevent the recurrence of the P22FA code?

Regular maintenance schedules typically do not specify a specific interval for NOx sensor inspection or replacement, but it is advisable to monitor the sensors for any signs of malfunction during routine vehicle checks.