AutoCodes – GMC – P22FA GMC

P22FA GMC 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 GMC 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 1,014

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 GMC 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 GMC - NOx Sensor 1 Performance Slow Response High To Low - AutoCodes.com — P22FA GMC Code - NOx Sensor 1 Performance Slow Response High To Low

What does this mean?

What are the Possible Causes of the DTC P22FA GMC?

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 GMC?

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 GMC 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 GMC code?

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

Need Help with the Code?

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Information for Specific GMC Models

P22FA 2014 GMC Sierra — NOx Sensor 1 Performance Slow Response High To Low
P22FA 2015 GMC Sierra — NOx Sensor 1 Performance Slow Response High To Low
P22FA 2016 GMC Sierra — NOx Sensor 1 Performance Slow Response High To Low
P22FA 2017 GMC Sierra — NOx Sensor 1 Performance Slow Response High To Low
P22FA 2018 GMC Sierra — 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 GMC Code

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

- Common symptoms include poor engine performance, decreased fuel efficiency, and the illumination of the check engine light.

2. What are the possible causes of OBDII code P22FA GMC?

- Possible causes include a faulty NOx sensor, wiring issues, exhaust leaks, or a problem with the engine control module.

3. How can I diagnose the OBDII code P22FA GMC?

- Diagnosing this code typically involves using a diagnostic scanner to retrieve the fault codes, checking the NOx sensor and its wiring for any visible damage, and performing a sensor test using a scan tool.

4. Can I continue driving my vehicle with OBDII code P22FA GMC?

- It is generally not recommended to continue driving with this code present, as it can lead to further damage to the vehicle and may cause it to fail emissions tests.

5. What are the repair options for OBDII code P22FA GMC?

- Repair options may include replacing the NOx sensor, repairing any wiring issues, fixing exhaust leaks, or reprogramming the engine control module.

6. How much does it cost to fix OBDII code P22FA GMC?

- The cost of fixing this code can vary depending on the specific issue causing it, but it may range from $200 to $800 or more, including parts and labor.

7. Can I reset the check engine light after fixing OBDII code P22FA GMC?

- Yes, once the underlying issue causing the code is addressed and repaired, the check engine light can be reset using a diagnostic scanner.

8. What should I do if OBDII code P22FA GMC keeps coming back after repair?

- If the code keeps returning after repair, it may indicate an ongoing issue that needs further diagnosis and attention from a qualified mechanic.

9. Is OBDII code P22FA GMC a serious problem?

- While the severity of this code may vary, it should not be ignored, as it can affect the performance and emissions of your vehicle.

10. How often should the NOx sensor be inspected to prevent OBDII code P22FA GMC?

- It is recommended to have the NOx sensor inspected during regular maintenance checks or if you experience any symptoms related to exhaust gas performance.