AutoCodes – Generic – P22A1

P22A1 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 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 17,536

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

What does this mean?

What are the Possible Causes of the DTC P22A1?

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?

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 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 code?

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Information for Specific Makes

P22A1 Buick — NOx Sensor 2 Circuit High Voltage
P22A1 Cadillac — NOx Sensor 2 Circuit High Voltage
P22A1 Chevrolet — NOx Sensor 2 Circuit High Voltage
P22A1 GMC — 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 Code

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

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

2. What are the possible causes of OBDII code P22A1?

- Potential causes include a faulty NOx sensor, wiring issues in the NOx sensor circuit, or problems with the engine control module (ECM).

3. How can I diagnose OBDII code P22A1?

- Diagnosis typically involves using a diagnostic scanner to retrieve the trouble codes and then conducting a thorough inspection of the NOx sensor, wiring, and related components.

4. Can I continue driving with OBDII code P22A1 present?

- It is not recommended to continue driving with this code present, as it can lead to further damage to the vehicle and potentially affect emissions compliance.

5. How can I repair OBDII code P22A1?

- Repairing this code often involves replacing the faulty NOx sensor, repairing any damaged wiring, or reprogramming the ECM if necessary.

6. Are there any DIY tips for fixing OBDII code P22A1?

- While some basic troubleshooting like checking connections and fuses can be done by DIY enthusiasts, it is recommended to consult a professional technician for a thorough diagnosis and repair.

7. How much does it cost to fix OBDII code P22A1?

- The cost of fixing this code can vary depending on the specific cause and the labor rates in your area. It's best to get a diagnostic assessment from a qualified mechanic.

8. How long does it take to repair OBDII code P22A1?

- The repair time can vary based on the extent of the issue and the availability of parts. In some cases, it can be resolved within a few hours, while more complex repairs may take longer.

9. Can a bad NOx sensor cause OBDII code P22A1?

- Yes, a malfunctioning NOx sensor, particularly NOx Sensor 2, can trigger the P22A1 code due to high voltage readings.

10. Is OBDII code P22A1 a serious issue?

- While not an emergency, it is important to address OBDII code P22A1 promptly to ensure optimal engine performance, fuel efficiency, and emissions compliance.