AutoCodes – Chevrolet – P22A8 Chevrolet

P22A8 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: P22A8 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 1,064

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 P22A8 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 P22A8 Chevrolet - NOx Sensor 2 Heater Feedback Circuit Low Voltage - AutoCodes.com — P22A8 Chevrolet Code - NOx Sensor 2 Heater Feedback Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A8 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 P22A8 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 P22A8 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 P22A8 Chevrolet code?

Need more information on how to fix the P22A8 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific Chevrolet Models

P22A8 2014 Chevrolet Silverado — NOx Sensor 2 Heater Feedback Circuit Low Voltage
P22A8 2015 Chevrolet Silverado — NOx Sensor 2 Heater Feedback Circuit Low Voltage
P22A8 2016 Chevrolet Silverado — NOx Sensor 2 Heater Feedback Circuit Low Voltage
P22A8 2017 Chevrolet Silverado — NOx Sensor 2 Heater Feedback Circuit Low Voltage
P22A8 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 P22A8 Chevrolet Code

1. What are the common symptoms of OBDII code P22A8 (NOx Sensor 2 Heater Feedback Circuit Low Voltage)?

- Common symptoms include reduced engine performance, increased fuel consumption, and an illuminated check engine light.

2. What are the potential causes of OBDII code P22A8 in a Chevrolet vehicle?

- The code P22A8 can be triggered by a faulty NOx sensor, damaged wiring or connectors, or issues with the heater circuit.

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

- Diagnose the problem by checking the sensor's wiring and connectors for damage, testing the sensor's resistance, and inspecting the heater circuit for faults.

4. Can driving with OBDII code P22A8 cause further damage to my Chevrolet?

- Continuing to drive with the code P22A8 can potentially lead to increased emissions, reduced fuel efficiency, and possible damage to other engine components.

5. What are some repair tips for resolving OBDII code P22A8 in a Chevrolet?

- Repair tips include replacing the faulty NOx sensor, repairing damaged wiring or connectors, and ensuring the heater circuit is functioning properly.

6. Is it safe to continue driving my Chevrolet with the NOx Sensor 2 Heater Feedback Circuit Low Voltage issue?

- It is not recommended to drive the vehicle with this issue as it can lead to further engine problems and increased emissions.

7. How much does it typically cost to repair OBDII code P22A8 in a Chevrolet?

- The cost of repairing this code can vary depending on the exact cause of the issue, but it may range from $200 to $600 including parts and labor.

8. Can I reset the check engine light after fixing OBDII code P22A8 in my Chevrolet?

- Yes, the check engine light can be reset using an OBDII scanner after the issue causing code P22A8 has been fixed.

9. How often does the NOx sensor in a Chevrolet need to be replaced?

- The NOx sensor in a Chevrolet typically does not need to be replaced often, but it can fail due to age, mileage, or environmental factors.

10. Are there any preventative maintenance steps to avoid OBDII code P22A8 in a Chevrolet?

- Regularly inspecting the NOx sensor, checking the wiring for damage, and addressing any engine performance issues promptly can help prevent code P22A8 from occurring.