AutoCodes – GMC – P22A8 2016 GMC Sierra

P22A8 2016 GMC Sierra 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 2016 GMC Sierra 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 143

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 2016 GMC Sierra 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 2016 GMC Sierra - NOx Sensor 2 Heater Feedback Circuit Low Voltage - AutoCodes.com — P22A8 2016 GMC Sierra Code - NOx Sensor 2 Heater Feedback Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A8 2016 GMC Sierra?

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 2016 GMC Sierra?

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 2016 GMC Sierra 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 2016 GMC Sierra code?

Need more information on how to fix the P22A8 2016 GMC Sierra 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 2016 GMC Sierra Code

1. What does the OBDII code P22A8 mean on a 2016 GMC Sierra?

P22A8 indicates a problem with the NOx Sensor 2 Heater Feedback Circuit showing low voltage, which can affect the vehicle's ability to monitor and reduce nitrogen oxide emissions.

2. What are common symptoms of code P22A8?

Symptoms include an illuminated check engine light, reduced fuel efficiency, possible power loss, and the vehicle entering limp mode.

3. What causes the P22A8 code to trigger?

Common causes include a faulty NOx sensor, damaged wiring or connectors in the NOx sensor circuit, or issues with the vehicle's powertrain control module (PCM).

4. Can I drive with a P22A8 code on my 2016 GMC Sierra?

Driving with this code is possible but not recommended, as it can result in higher emissions, reduced performance, and potential damage to the exhaust system over time.

5. How do I diagnose the P22A8 code?

Use an OBDII scanner to confirm the code, visually inspect the wiring and connectors for damage, and test the NOx sensor heater circuit for proper resistance and voltage.

6. How is the P22A8 code repaired?

Repairs may include replacing the NOx sensor, repairing or replacing damaged wiring or connectors, or reprogramming/updating the PCM if necessary.

7. What tools are needed to fix a P22A8 code?

Tools typically include an OBDII scanner, a multimeter for testing circuits, and basic hand tools for sensor replacement or wiring repairs.

8. How much does it cost to fix the P22A8 code?

Repair costs vary but typically range from $300 to $700, depending on whether the NOx sensor needs replacement or if wiring issues are present.

9. Can a faulty NOx sensor cause other issues in my 2016 GMC Sierra?

Yes, a faulty NOx sensor can lead to increased emissions, reduced engine performance, and potentially damage other components in the emissions system.

10. Is the P22A8 code covered under warranty for my 2016 GMC Sierra?

It may be covered under the emissions warranty, depending on the vehicle's mileage and service history. Check with your dealership for specific warranty details.