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P22A5 2017 GMC Sierra Code - NOx Sensor 2 Heater Control Circuit High 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
P22A5 2017 GMC Sierra indicates NOx Sensor 2 Heater Control Circuit High 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 191
How popular is this code, among other codes? Low
What is this?
Table of contents Created and updated by William Orellana on Mar 24, 2024
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Code P22A5 2017 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 P22A5 2017 GMC Sierra - NOx Sensor 2 Heater Control Circuit High Voltage - AutoCodes.com
P22A5 2017 GMC Sierra Code - NOx Sensor 2 Heater Control Circuit High Voltage
What does this mean?

What are the Possible Causes of the DTC P22A5 2017 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 P22A5 2017 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 P22A5 2017 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 P22A5 2017 GMC Sierra code?

Need more information on how to fix the P22A5 2017 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 P22A5 2017 GMC Sierra Code

1. What does code P22A5 mean on a 2017 GMC Sierra?

Code P22A5 indicates a problem with the NOx sensor 2 heater control circuit, specifically reporting high voltage.

2. What are the symptoms of code P22A5 in a 2017 GMC Sierra?

Common symptoms include the check engine light turning on, reduced fuel efficiency, possible limp mode activation, and increased emissions.

3. What causes the P22A5 code in a 2017 GMC Sierra?

Potential causes include a faulty NOx sensor 2, damaged or corroded wiring/connectors, a bad heater control circuit, or an issue with the ECM.

4. Can I drive my 2017 GMC Sierra with a P22A5 code?

While the vehicle may still be drivable, prolonged driving with this code can lead to damage to the emissions system and decreased performance.

5. How do I diagnose the P22A5 code in my 2017 GMC Sierra?

Start by inspecting the NOx sensor 2 wiring and connectors for damage, then use a diagnostic scanner to confirm sensor and circuit functionality.

6. How much does it cost to fix a P22A5 code on a 2017 GMC Sierra?

Repair costs can range from $200 to $600, depending on whether the NOx sensor or related components need replacement.

7. Can a P22A5 code cause emissions test failure?

Yes, since the NOx sensor is crucial for monitoring and controlling emissions, a P22A5 code can result in an emissions test failure.

8. How do I fix the P22A5 code on my 2017 GMC Sierra?

Repairs may include replacing the NOx sensor 2, repairing damaged wiring, or addressing issues in the heater control circuit.

9. Is a faulty NOx sensor 2 the only cause of a P22A5 code?

No, while a faulty sensor is common, other causes include wiring issues, ECM faults, or damage to the heater control circuit.

10. Does a P22A5 code always require part replacement?

Not necessarily. Sometimes the issue can be resolved by repairing or cleaning connections, though sensor replacement is often necessary.

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