AutoCodes – GMC – P22A1 GMC

P22A1 GMC Code - NOx Sensor 2 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: P22A1 GMC indicates NOx Sensor 2 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 2,409

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 P22A1 GMC 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 P22A1 GMC - NOx Sensor 2 Circuit High Voltage - AutoCodes.com — P22A1 GMC Code - NOx Sensor 2 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P22A1 GMC?

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 P22A1 GMC?

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 P22A1 GMC 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 P22A1 GMC code?

Need more information on how to fix the P22A1 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific GMC Models

P22A1 2014 GMC Sierra — NOx Sensor 2 Circuit High Voltage
P22A1 2015 GMC Sierra — NOx Sensor 2 Circuit High Voltage
P22A1 2016 GMC Sierra — NOx Sensor 2 Circuit High Voltage
P22A1 2017 GMC Sierra — NOx Sensor 2 Circuit High Voltage
P22A1 2018 GMC Sierra — NOx Sensor 2 Circuit High 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 P22A1 GMC Code

1. What are common symptoms of OBDII code P22A1 GMC (NOx Sensor 2 Circuit High Voltage)?

- Common symptoms include poor engine performance, decreased fuel efficiency, illuminated Check Engine Light, and potential emission issues.

2. What can cause the OBDII code P22A1 GMC to trigger?

- The code P22A1 GMC is typically triggered by issues such as a faulty NOx sensor, damaged wiring harness, or a problem with the NOx sensor circuit.

3. How can I diagnose the NOx Sensor 2 Circuit High Voltage issue?

- Diagnosis usually involves using an OBDII scanner to retrieve the specific fault code, checking the NOx sensor and its wiring harness for any visible damage, and testing the sensor's voltage.

4. Can driving with the P22A1 GMC code cause further damage to the vehicle?

- Continuing to drive with the P22A1 GMC code may lead to increased emissions, potential damage to the catalytic converter, and further deterioration of the vehicle's overall performance.

5. How can I repair the NOx Sensor 2 Circuit High Voltage issue?

- Repair options may include replacing the faulty NOx sensor, repairing any damaged wiring harness, resetting the fault code with an OBDII scanner, and conducting a thorough test drive to ensure the issue is resolved.

6. Is it safe to ignore the P22A1 GMC code and continue driving the vehicle?

- Ignoring the P22A1 GMC code can lead to more serious problems over time, affecting both vehicle performance and emissions compliance. It is recommended to address the issue promptly.

7. Can a DIY enthusiast fix the NOx Sensor 2 Circuit High Voltage problem?

- While some experienced DIY enthusiasts may be able to replace the NOx sensor or repair the wiring harness, it is recommended to consult a professional mechanic for accurate diagnosis and repair of this issue.

8. How much does it typically cost to repair the P22A1 GMC code?

- The cost of repairing the NOx Sensor 2 Circuit High Voltage issue can vary depending on the extent of the problem, the need for parts replacement, and labor costs. It is advisable to obtain quotes from local repair shops.

9. Are there any preventive measures to avoid triggering the P22A1 GMC code in the future?

- Regular vehicle maintenance, including checking the NOx sensor and its wiring harness for signs of wear or damage, can help prevent the recurrence of the NOx Sensor 2 Circuit High Voltage issue.

10. Will resetting the fault code with an OBDII scanner permanently fix the P22A1 GMC code?

- Resetting the fault code may temporarily turn off the Check Engine Light, but if the underlying issue such as a faulty NOx sensor or wiring problem persists, the code is likely to reappear. It is essential to address the root cause of the problem for a permanent fix.