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P22A7 Chevrolet Code - NOx Sensor 2 Heater Feedback Performance

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 2, Nitrogen Oxides Sensor 2 harness is open or shorted, Nitrogen Oxides Sensor 2 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
P22A7 Chevrolet indicates NOx Sensor 2 Heater Feedback Performance.
Common causes
Common causes include Faulty Nitrogen Oxides (NOx) Sensor 2, Nitrogen Oxides Sensor 2 harness is open or shorted, Nitrogen Oxides Sensor 2 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 1,649
How popular is this code, among other codes? Low
What is this?
Table of contents Created and updated by William Orellana on Mar 24, 2024
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Code P22A7 Chevrolet 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 P22A7 Chevrolet - NOx Sensor 2 Heater Feedback Performance - AutoCodes.com
P22A7 Chevrolet Code - NOx Sensor 2 Heater Feedback Performance
What does this mean?

What are the Possible Causes of the DTC P22A7 Chevrolet?

  • Faulty Nitrogen Oxides (NOx) Sensor 2
  • Nitrogen Oxides Sensor 2 harness is open or shorted
  • Nitrogen Oxides Sensor 2 circuit poor electrical connection

How to Fix the DTC P22A7 Chevrolet?

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 P22A7 Chevrolet 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 P22A7 Chevrolet code?

Need more information on how to fix the P22A7 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P22A7 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

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 P22A7 Chevrolet Code

1. What are the common symptoms of OBDII code P22A7 Chevrolet (NOx Sensor 2 Heater Feedback Performance)?

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

2. What causes the OBDII code P22A7 Chevrolet (NOx Sensor 2 Heater Feedback Performance) to trigger?

- The code is typically triggered when the powertrain control module detects a performance issue with the heater circuit of the NOx Sensor 2.

3. How serious is the OBDII code P22A7 Chevrolet (NOx Sensor 2 Heater Feedback Performance)?

- While the vehicle may still be operable with this code, ignoring it can lead to increased emissions and potential long-term damage to the catalytic converter.

4. Can I continue driving my vehicle with the OBDII code P22A7 Chevrolet (NOx Sensor 2 Heater Feedback Performance) present?

- It is recommended to address the issue promptly to prevent any further damage or performance issues in the long run.

5. How can I diagnose the OBDII code P22A7 Chevrolet (NOx Sensor 2 Heater Feedback Performance)?

- Diagnosing this code typically involves using a diagnostic scanner to retrieve the specific trouble code and then testing the NOx Sensor 2 heater circuit for proper operation.

6. What are some possible repair tips for fixing the OBDII code P22A7 Chevrolet (NOx Sensor 2 Heater Feedback Performance)?

- Repair tips may include checking and replacing the NOx Sensor 2 heater, inspecting the wiring for any damage, and resetting the fault codes after repairs are made.

7. Is it possible to reset the OBDII code P22A7 Chevrolet (NOx Sensor 2 Heater Feedback Performance) without fixing the underlying issue?

- Resetting the code without addressing the underlying problem may temporarily turn off the check engine light, but the code is likely to reappear until the issue is resolved.

8. How much does it typically cost to repair the OBDII code P22A7 Chevrolet (NOx Sensor 2 Heater Feedback Performance)?

- The cost of repair can vary depending on the exact cause of the issue, but it may range from $200 to $500, including parts and labor.

9. Can a DIY enthusiast fix the OBDII code P22A7 Chevrolet (NOx Sensor 2 Heater Feedback Performance)?

- While some enthusiasts may have the skills to diagnose and repair this issue, it is recommended to consult a professional mechanic for proper diagnosis and repair to ensure the issue is resolved correctly.

10. How often does the OBDII code P22A7 Chevrolet (NOx Sensor 2 Heater Feedback Performance) occur in vehicles?

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

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