AutoCodes – Generic – P22A5

P22A5 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 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 4,630

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 P22A5 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 - NOx Sensor 2 Heater Control Circuit High Voltage - AutoCodes.com — P22A5 Code - NOx Sensor 2 Heater Control Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P22A5?

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?

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 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

P22A5 Buick — NOx Sensor 2 Heater Control Circuit High Voltage
P22A5 Cadillac — NOx Sensor 2 Heater Control Circuit High Voltage
P22A5 Chevrolet — NOx Sensor 2 Heater Control Circuit High Voltage
P22A5 GMC — NOx Sensor 2 Heater Control 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 P22A5 Code

1. What are the common symptoms of OBDII code P22A5 related to NOx Sensor 2 Heater Control Circuit High Voltage?

- Common symptoms may include a check engine light, reduced engine performance, and potential failures to pass emissions testing.

2. What are the possible causes of OBDII code P22A5 NOx Sensor 2 Heater Control Circuit High Voltage?

- Possible causes include a faulty NOx sensor, damaged wiring or connectors, a malfunctioning heater control circuit, or issues with the vehicle's engine control module.

3. How serious is OBDII code P22A5 NOx Sensor 2 Heater Control Circuit High Voltage?

- While the vehicle may still be operable with this code, it is important to address it promptly to prevent potential damage to the vehicle's emission control system and ensure optimal engine performance.

4. Can I continue driving with OBDII code P22A5 present?

- It is not recommended to ignore this code and continue driving without addressing the underlying issue, as it may lead to further damage and potentially affect the vehicle's emissions.

5. How can I diagnose OBDII code P22A5 NOx Sensor 2 Heater Control Circuit High Voltage?

- Diagnosis typically involves using an OBDII scanner to retrieve the code, inspecting the NOx sensor and related components, and testing the heater control circuit for proper functionality.

6. What are some repair tips for fixing OBDII code P22A5?

- Repair tips may include checking and repairing any damaged wiring or connectors, replacing the NOx sensor if faulty, and ensuring the heater control circuit is functioning correctly.

7. Is it possible to reset OBDII code P22A5 without fixing the underlying issue?

- While clearing the code may temporarily turn off the check engine light, it will likely reappear if the root cause of the problem is not addressed.

8. How much does it typically cost to repair OBDII code P22A5 NOx Sensor 2 Heater Control Circuit High Voltage?

- The cost of repair can vary depending on the specific issue causing the code, the labor rates of the repair shop, and the cost of any replacement parts needed.

9. Can a DIY enthusiast fix OBDII code P22A5 at home?

- Depending on your mechanical skills and access to tools, some DIY enthusiasts may be able to diagnose and repair OBDII code P22A5 at home. However, it is recommended to consult with a professional if unsure.

10. How can I prevent OBDII code P22A5 from recurring in the future?

- Regular maintenance, such as checking and replacing sensors as needed, keeping up with engine tune-ups, and addressing any warning lights promptly, can help prevent OBDII code P22A5 from recurring.