AutoCodes – GMC – P22F9 2018 GMC Sierra

P22F9 2018 GMC Sierra 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 2018 GMC Sierra 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 153

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 P22F9 2018 GMC Sierra 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 2018 GMC Sierra - NOx Sensor 1 Performance Slow Response Low To High - AutoCodes.com — P22F9 2018 GMC Sierra Code - NOx Sensor 1 Performance Slow Response Low To High

What does this mean?

What are the Possible Causes of the DTC P22F9 2018 GMC Sierra?

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 2018 GMC Sierra?

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 2018 GMC Sierra 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 2018 GMC Sierra code?

Need more information on how to fix the P22F9 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P22F9 2018 GMC Sierra 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 P22F9 2018 GMC Sierra Code

1. What does the OBDII code P22F9 mean for a 2018 GMC Sierra?

P22F9 indicates a performance issue with NOx Sensor 1, specifically a slow response when transitioning from low to high readings.

2. What are the common symptoms of code P22F9 on a 2018 GMC Sierra?

Symptoms may include an illuminated check engine light, reduced fuel efficiency, increased emissions, or the vehicle entering limp mode.

3. What causes the P22F9 code to appear on a 2018 GMC Sierra?

Common causes include a malfunctioning NOx sensor, damaged wiring or connectors, exhaust leaks, or software issues in the engine control module (ECM).

4. Can you drive a 2018 GMC Sierra with the P22F9 code?

Driving with this code is not recommended as it can lead to higher emissions, reduced performance, and potential damage to the emissions system.

5. How do you diagnose the P22F9 code on a 2018 GMC Sierra?

Diagnosis involves scanning the ECM for codes, inspecting the NOx sensor and its wiring, checking for exhaust leaks, and verifying sensor performance with a scan tool.

6. How do you fix the P22F9 code on a 2018 GMC Sierra?

Common fixes include replacing the NOx sensor, repairing damaged wiring, addressing exhaust leaks, or updating the ECM software.

7. How much does it cost to repair a P22F9 code on a 2018 GMC Sierra?

Repair costs can range from $200 to $600, depending on whether the NOx sensor needs replacement or if other repairs like fixing wiring or leaks are required.

8. Can a bad NOx sensor damage other components in a 2018 GMC Sierra?

Yes, a faulty NOx sensor can cause improper operation of the emissions system, potentially leading to damage to the catalytic converter or other components over time.

9. How do I prevent the P22F9 code from reoccurring in my 2018 GMC Sierra?

Regular maintenance, using high-quality diesel fuel, and promptly addressing exhaust system issues can help prevent this code.

10. Is the P22F9 code covered under warranty for a 2018 GMC Sierra?

It may be covered under the emissions warranty, depending on the vehicle's age and mileage. Check with your dealership or warranty documentation for details.