AutoCodes – Generic – P22F9

P22F9 Code - NOx Sensor 1 Performance Slow Response Low To High

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: P22F9 indicates NOx Sensor 1 Performance Slow Response Low To High.
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 4,829

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 P22F9 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 P22F9 - NOx Sensor 1 Performance Slow Response Low To High - AutoCodes.com — P22F9 Code - NOx Sensor 1 Performance Slow Response Low To High

What does this mean?

What are the Possible Causes of the DTC P22F9?

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 P22F9?

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 P22F9 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 P22F9 code?

Need more information on how to fix the P22F9 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P22F9 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P22F9 Buick — NOx Sensor 1 Performance Slow Response Low To High
P22F9 Cadillac — NOx Sensor 1 Performance Slow Response Low To High
P22F9 Chevrolet — NOx Sensor 1 Performance Slow Response Low To High
P22F9 GMC — NOx Sensor 1 Performance Slow Response Low To High

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 P22F9 Code

1. What are the common symptoms of OBDII code P22F9 (NOx Sensor 1 Performance Slow Response Low To High)?

The common symptoms include poor engine performance, reduced fuel efficiency, and the illumination of the check engine light.

2. What are the possible causes of OBDII code P22F9?

Possible causes of this code include a faulty NOx sensor, wiring issues, exhaust system leaks, and problems with the engine control module.

3. How can I diagnose the cause of OBDII code P22F9?

Diagnosis typically involves using a scan tool to retrieve the code, checking the NOx sensor's operation, inspecting the wiring for damage, and examining the exhaust system for leaks.

4. Can a dirty or contaminated NOx sensor trigger code P22F9?

Yes, a dirty or contaminated NOx sensor may lead to slow response times and trigger OBDII code P22F9.

5. What are some repair tips for OBDII code P22F9?

Repair tips include cleaning or replacing the NOx sensor, repairing any damaged wiring, fixing exhaust leaks, and ensuring proper communication between the sensor and the engine control module.

6. Is it safe to continue driving with OBDII code P22F9 present?

It is generally not recommended to drive with this code active, as it can lead to further damage to the vehicle's emissions system and potentially affect engine performance.

7. How much does it typically cost to repair OBDII code P22F9?

The cost of repairing this code can vary depending on the exact cause, but it may range from $200 to $800, including parts and labor.

8. Can a DIY enthusiast fix OBDII code P22F9 at home?

Some aspects of diagnosing and repairing this code may be tackled by experienced DIY enthusiasts, but it is advisable to consult a professional mechanic for a proper diagnosis and repair.

9. How often does OBDII code P22F9 occur in vehicles?

This code is relatively uncommon compared to other OBDII codes, but it can still occur in vehicles equipped with NOx sensors.

10. Are there any recalls related to OBDII code P22F9?

Recalls related to this specific code may vary depending on the vehicle make and model, so it is recommended to check with the manufacturer or a dealership for any relevant information.