AutoCodes – Chevrolet – P22A9 Chevrolet

P22A9 Chevrolet Code - NOx Sensor 2 Heater Feedback Circuit Low Voltage

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: P22A9 Chevrolet indicates NOx Sensor 2 Heater Feedback Circuit Low Voltage.
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 496

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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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 P22A9 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 P22A9 Chevrolet - NOx Sensor 2 Heater Feedback Circuit Low Voltage - AutoCodes.com — P22A9 Chevrolet Code - NOx Sensor 2 Heater Feedback Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A9 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 P22A9 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 P22A9 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 P22A9 Chevrolet code?

Need more information on how to fix the P22A9 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P22A9 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

P22A9 2014 Chevrolet Silverado — NOx Sensor 2 Heater Feedback Circuit Low Voltage
P22A9 2015 Chevrolet Silverado — NOx Sensor 2 Heater Feedback Circuit Low Voltage
P22A9 2016 Chevrolet Silverado — NOx Sensor 2 Heater Feedback Circuit Low Voltage
P22A9 2017 Chevrolet Silverado — NOx Sensor 2 Heater Feedback Circuit Low Voltage
P22A9 2018 Chevrolet Silverado — NOx Sensor 2 Heater Feedback Circuit Low Voltage

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 P22A9 Chevrolet Code

1. What are the common symptoms of OBDII code P22A9 in a Chevrolet related to NOx Sensor 2 Heater Feedback Circuit Low Voltage?

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

2. What can cause the NOx Sensor 2 Heater Feedback Circuit Low Voltage issue in a Chevrolet triggering code P22A9?

- Possible causes can include a faulty NOx sensor, damaged wiring or connectors, a blown fuse, or a malfunctioning ECM.

3. How can I diagnose the NOx Sensor 2 Heater Feedback Circuit Low Voltage problem in my Chevrolet?

- Diagnosis involves using an OBDII scanner to retrieve the specific fault code P22A9 and then conducting a thorough inspection of the NOx sensor, wiring, connectors, and related components.

4. Is it safe to continue driving my Chevrolet with OBDII code P22A9 indicating NOx Sensor 2 Heater Feedback Circuit Low Voltage?

- While the vehicle may still be operable, it is recommended to address the issue promptly to prevent potential damage to the catalytic converter and ensure optimal engine performance.

5. Can I repair the NOx Sensor 2 Heater Feedback Circuit Low Voltage problem in my Chevrolet myself?

- Depending on your skill level and access to tools, you may be able to address the issue by replacing the faulty NOx sensor, repairing damaged wiring, or checking and replacing any blown fuses. However, professional assistance is recommended for accurate diagnosis and repair.

6. How much does it typically cost to repair OBDII code P22A9 related to the NOx Sensor 2 Heater Feedback Circuit Low Voltage in a Chevrolet?

- Repair costs can vary widely based on the specific cause of the issue, the need for replacement parts, and labor charges. It is advisable to consult a mechanic for an accurate estimate.

7. Can a bad NOx Sensor 2 Heater Feedback Circuit Low Voltage impact the emissions of my Chevrolet?

- Yes, a malfunctioning NOx sensor can affect the vehicle's emissions output, potentially leading to increased pollution and non-compliance with emissions regulations.

8. Are there any preventive measures to avoid encountering OBDII code P22A9 in my Chevrolet due to NOx Sensor 2 Heater Feedback Circuit Low Voltage?

- Regular maintenance, timely repairs, and avoiding harsh driving conditions can help prevent issues with the NOx sensor and related components, reducing the likelihood of triggering this fault code.

9. How important is the NOx Sensor 2 Heater Feedback Circuit in a Chevrolet's emissions control system?

- The NOx Sensor 2 Heater Feedback Circuit plays a crucial role in monitoring and regulating the nitrogen oxide levels in the exhaust gases, contributing to the overall efficiency and environmental friendliness of the vehicle.

10. Can resetting the OBDII system clear the P22A9 code related to the NOx Sensor 2 Heater Feedback Circuit Low Voltage in a Chevrolet?

- While clearing the code may temporarily turn off the check engine light, it is essential to address the underlying issue causing the fault code to prevent further problems and ensure proper vehicle operation.