Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
There's a problem with a part in the car that checks how clean the air coming out of the car is. This part is called a NOx sensor, and it's like a nose that sniffs the car's exhaust to make sure it's not too dirty.
The P229E code indicates an issue with the NOx (Nitrogen Oxide) sensor circuit for Bank 1 Sensor 2, which monitors the level of nitrogen oxides in the exhaust gases.
The NOx sensor is responsible for measuring the concentration of nitrogen oxides in the exhaust gases. Bank 1 refers to the side of the engine with cylinder 1, and Sensor 2 typically indicates the sensor located downstream of the catalytic converter. A fault in this sensor's circuit can lead to improper readings, affecting engine performance and emissions.
• Check Engine Light (CEL) is on
• Reduced fuel efficiency
• Poor engine performance
• Faulty NOx sensor
• Wiring issues such as damaged wires or poor connections
• ECU (Engine Control Unit) malfunction
NOx: Nitrogen Oxides, pollutants produced during combustion
ECU: Engine Control Unit, the computer that controls engine functions
• Use an OBD-II scanner to confirm the code
• Inspect the NOx sensor and its wiring for damage
• Test the sensor's voltage and resistance
• Replace the faulty NOx sensor
• Repair or replace damaged wiring
• Reprogram or replace the ECU if necessary
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Volkswagen Jetta
• Audi A4
• BMW 3 Series
• Regular maintenance checks
• Ensure proper fuel quality
• Inspect exhaust system periodically
Sensor Issue
• Get the vehicle checked by a professional mechanic
• Avoid driving for long distances until the issue is resolved
Check with your vehicle manufacturer for warranty coverage on emissions-related components.
The P229E code has been more common in vehicles with advanced emissions systems, especially diesel engines.
Moderate – While the vehicle may still be drivable, it's important to address emissions issues to avoid further damage and to comply with emissions standards.
Driving with a faulty NOx sensor can lead to increased emissions, which may not comply with legal standards and could result in fines.
• Engine at operating temperature
• Vehicle driven under normal conditions
The NOx sensor is typically located in the exhaust system, downstream of the catalytic converter on the side of the engine with cylinder 1.
Q: Can I drive with a P229E code?
A: While you might be able to drive with this code, it's best to fix it soon to avoid emissions issues and potential engine damage.
Q: How do I know if my NOx sensor is bad?
A: Common signs include a check engine light, reduced fuel efficiency, and poor engine performance.
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Universal · Digital multimeter
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Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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Fitment Required · Vehicle-fitment part
Relevant when catalyst-efficiency or emissions faults persist after proper diagnosis.
Catalyst-efficiency faults sometimes point toward converter problems after proper testing.
Catalytic converters are highly vehicle-specific and should not be purchased by code alone.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.