AutoCodes – Chevrolet – P22A8 2018 Chevrolet Silverado

P22A8 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado 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 218

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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado - NOx Sensor 2 Heater Feedback Circuit Low Voltage - AutoCodes.com — P22A8 2018 Chevrolet Silverado Code - NOx Sensor 2 Heater Feedback Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A8 2018 Chevrolet Silverado?

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 2018 Chevrolet Silverado?

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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado code?

Need more information on how to fix the P22A8 2018 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 2018 Chevrolet Silverado Code

1. What does the OBDII code P22A8 on a 2018 Chevrolet Silverado indicate?

The code P22A8 indicates an issue with the NOx Sensor 2 Heater Feedback Circuit showing low voltage.

2. What are common symptoms associated with the P22A8 code in a 2018 Chevrolet Silverado?

Common symptoms include the malfunction indicator light (MIL) being illuminated on the dashboard and potential poor engine performance.

3. What are possible causes of the NOx Sensor 2 Heater Feedback Circuit low voltage issue in a 2018 Chevrolet Silverado?

Possible causes may include a faulty NOx sensor, damaged wiring or connectors, a malfunctioning heater circuit, or issues with the vehicle's engine control module (ECM).

4. How can I diagnose the P22A8 code in my 2018 Chevrolet Silverado?

Diagnosis typically involves using an OBDII scanner to retrieve the specific fault code, checking the wiring and connectors for any visible damage, and testing the NOx sensor and heater circuit for proper functionality.

5. Can I continue driving my 2018 Chevrolet Silverado with the P22A8 code present?

It is not recommended to continue driving with the P22A8 code present, as prolonged driving with this issue unresolved may lead to poor fuel efficiency and potential damage to the vehicle's emissions system.

6. How can I repair the NOx Sensor 2 Heater Feedback Circuit low voltage issue in my 2018 Chevrolet Silverado?

Repair options may include replacing the faulty NOx sensor, repairing or replacing damaged wiring and connectors, fixing the heater circuit, or reprogramming the ECM.

7. Is it possible to reset the P22A8 code in a 2018 Chevrolet Silverado without repairing the issue?

While clearing the fault code using an OBDII scanner may temporarily turn off the MIL, the underlying issue causing the code will persist until properly diagnosed and repaired.

8. How much does it typically cost to repair the NOx Sensor 2 Heater Feedback Circuit low voltage problem in a 2018 Chevrolet Silverado?

The cost of repair can vary depending on the exact cause of the issue, but it may range from a few hundred to over a thousand dollars, including parts and labor.

9. Are there any recalls or technical service bulletins related to the P22A8 code in 2018 Chevrolet Silverado models?

It is advisable to check with a Chevrolet dealership or consult online resources for any relevant recalls or technical service bulletins related to the NOx Sensor 2 Heater Feedback Circuit low voltage issue in 2018 Silverado models.

10. How often should the NOx sensor be replaced in a 2018 Chevrolet Silverado as part of routine maintenance?

The NOx sensor generally does not have a specific replacement interval as part of routine maintenance. However, if issues arise with the sensor or related components, it should be inspected and replaced as necessary.