AutoCodes – Generic – P22A0

P22A0 Code - NOx Sensor 2 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: P22A0 indicates NOx Sensor 2 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 11,457

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
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Code P22A0 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 P22A0 - NOx Sensor 2 Circuit Low Voltage - AutoCodes.com — P22A0 Code - NOx Sensor 2 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P22A0?

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 P22A0?

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 P22A0 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.

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Information for Specific Makes

P22A0 Buick — NOx Sensor 2 Circuit Low Voltage
P22A0 Cadillac — NOx Sensor 2 Circuit Low Voltage
P22A0 Chevrolet — NOx Sensor 2 Circuit Low Voltage
P22A0 GMC — NOx Sensor 2 Circuit Low 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 P22A0 Code

1. What are the common symptoms of OBDII code P22A0 (NOx Sensor 2 Circuit Low Voltage)?

- Common symptoms include poor engine performance, decreased fuel efficiency, and illuminated check engine light.

2. What are the possible causes of OBDII code P22A0?

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

3. How can I diagnose the cause of OBDII code P22A0?

- Diagnosing the issue involves using a diagnostic scanner to retrieve the trouble codes, inspecting the NOx sensor and its wiring, and testing the sensor's voltage readings.

4. Can driving with OBDII code P22A0 cause further damage to my vehicle?

- Continuing to drive with this code may lead to increased emissions, reduced engine efficiency, and potential damage to the catalytic converter over time.

5. How can I repair OBDII code P22A0 (NOx Sensor 2 Circuit Low Voltage) myself?

- DIY repairs may involve replacing the NOx sensor, repairing or replacing damaged wiring, or resetting the engine control module after making necessary repairs.

6. Is it safe to ignore OBDII code P22A0 and continue driving my vehicle?

- It is not recommended to ignore this code, as it can lead to increased emissions and potential engine performance issues that may affect the overall drivability of the vehicle.

7. Are there any maintenance tips to prevent OBDII code P22A0 from occurring?

- Regularly servicing and maintaining your vehicle, including inspecting the NOx sensor and related components, can help prevent issues that trigger this fault code.

8. How much does it typically cost to repair OBDII code P22A0 at a professional auto repair shop?

- The cost of repairs for this code can vary depending on the exact cause of the issue, but it may range from $200 to $500 or more, including parts and labor.

9. Can a faulty NOx sensor cause other OBDII codes to appear in addition to P22A0?

- Yes, a malfunctioning NOx sensor can trigger related fault codes, such as P22A1 (NOx Sensor 2 Circuit High Voltage) or other emissions-related codes.

10. How long does it take to repair OBDII code P22A0 in a typical auto repair shop?

- Repair times can vary based on the complexity of the issue and availability of parts, but resolving this fault code usually takes a few hours to a full day at an auto repair shop.