AutoCodes – Chevrolet – P22A9 2018 Chevrolet Silverado

P22A9 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: P22A9 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 222

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 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P22A9 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 P22A9 2018 Chevrolet Silverado - NOx Sensor 2 Heater Feedback Circuit Low Voltage - AutoCodes.com — P22A9 2018 Chevrolet Silverado Code - NOx Sensor 2 Heater Feedback Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A9 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 P22A9 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 P22A9 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 P22A9 2018 Chevrolet Silverado code?

Need more information on how to fix the P22A9 2018 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P22A9 2018 Chevrolet Silverado code diagnosed by a professional: Find a repair shop in your area

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 2018 Chevrolet Silverado Code

1. What does OBDII code P22A9 mean on a 2018 Chevrolet Silverado?

This code indicates a low voltage condition in the NOx Sensor 2 heater feedback circuit.

2. What are common symptoms of OBDII code P22A9 in a 2018 Chevrolet Silverado?

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

3. What are possible causes of the NOx Sensor 2 Heater Feedback Circuit Low Voltage code in a 2018 Chevrolet Silverado?

Potential causes include a faulty NOx sensor, damaged wiring or connectors in the circuit, or a malfunctioning engine control module.

4. How can I diagnose the issue causing OBDII code P22A9 in my 2018 Chevrolet Silverado?

You can use a diagnostic scanner to read the code, inspect the NOx sensor and its wiring for damage, and test the sensor's heater circuit for proper voltage.

5. Can I continue driving my 2018 Chevrolet Silverado with OBDII code P22A9 present?

It's not recommended to drive with this code active, as it can lead to increased emissions, potential damage to other components, and may cause the vehicle to fail an emissions test.

6. How can I repair OBDII code P22A9 in my 2018 Chevrolet Silverado?

Repair options may include replacing the NOx sensor, repairing damaged wiring or connectors, or reprogramming the engine control module if needed.

7. Is it possible to reset OBDII code P22A9 in a 2018 Chevrolet Silverado without fixing the underlying issue?

While you can clear the code with a diagnostic scanner, it will likely reappear if the root cause of the low voltage condition in the NOx sensor heater circuit is not addressed.

8. Are there any preventative maintenance tips to avoid OBDII code P22A9 in a 2018 Chevrolet Silverado?

Regularly inspecting and maintaining the NOx sensor, ensuring proper wiring connections, and following the manufacturer's recommended service intervals can help prevent this issue.

9. Can a DIY enthusiast tackle the repair for OBDII code P22A9 in a 2018 Chevrolet Silverado?

Depending on your skill level and access to tools, you may be able to replace the NOx sensor or repair wiring yourself. However, advanced diagnostics and programming may require professional assistance.

10. How long does it typically take to repair OBDII code P22A9 in a 2018 Chevrolet Silverado?

The repair time can vary based on the exact cause of the issue, but replacing the NOx sensor or repairing wiring connections usually takes a few hours to complete.