Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with a special sensor in your car that checks the gases coming out of the engine. It's like a nose that sniffs the air to make sure it's clean.
The P23C1 code indicates that the NOx (Nitrogen Oxide) sensor on Bank 1, Sensor 3 is not performing as expected.
The NOx sensor measures the concentration of nitrogen oxides in the exhaust gases. This information is used by the engine control module (ECM) to optimize the combustion process and reduce emissions. A performance issue with this sensor means it may not be providing accurate data.
• Check Engine Light is on
• Reduced fuel efficiency
• Increased emissions
• Faulty NOx sensor
• Wiring issues such as open or short circuits
• Exhaust leaks affecting sensor readings
NOx Sensor: A sensor that measures the concentration of nitrogen oxides in the exhaust gases.
Bank 1: Refers to the side of the engine with cylinder 1 in a V-type engine.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connections to the NOx sensor.
• Test the NOx sensor for proper operation.
• Replace the faulty NOx sensor.
• Repair or replace damaged wiring.
• Fix any exhaust leaks.
• OBD-II scanner
• Multimeter
• Wrench set
$200 - $500
Moderate
• Volkswagen Jetta
• BMW 3 Series
• Audi A4
• Regularly inspect and maintain the exhaust system.
• Use high-quality fuel to reduce sensor contamination.
• Perform regular vehicle maintenance.
Sensor Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if unsure.
• Regularly maintain your vehicle to prevent sensor issues.
Check with your vehicle manufacturer for specific warranty coverage on emissions-related components.
NOx sensor issues have been reported more frequently as emission standards have become stricter.
Moderate – Addressing this issue will help maintain fuel efficiency and reduce emissions.
Driving with a faulty NOx sensor may lead to increased emissions, which could violate environmental regulations.
• Engine at operating temperature
• Vehicle running at steady speed
The NOx sensor is typically located in the exhaust system, near the catalytic converter.
Q: Can I drive with a P23C1 code?
A: While you can drive with this code, it's best to address it soon to avoid increased emissions and potential engine performance issues.
Q: How often should I replace the NOx sensor?
A: NOx sensors typically last between 50,000 to 100,000 miles, but this can vary depending on driving conditions and maintenance.
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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.