Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that a sensor in the car that checks for pollution is not working as fast as it should. It's like when you ask a friend a question and they take too long to answer.
The NOx sensor is slow to respond when the levels of nitrogen oxides (NOx) drop.
The P24F4 code indicates that the NOx sensor located on Bank 1, Sensor 1, is not responding quickly enough to changes in NOx levels from high to low. This slow response can affect the vehicle's emission control system.
• Check Engine Light illuminated
• Poor fuel economy
• Failed emissions test
• Faulty NOx sensor
• Wiring issues in the NOx sensor circuit
• Exhaust leaks affecting sensor readings
NOx: Nitrogen Oxides, pollutants produced during combustion.
Bank 1: The side of the engine with cylinder 1.
• Use an OBD-II scanner to confirm the code.
• Inspect the NOx sensor and its wiring for damage.
• Perform a NOx sensor response test.
• Replace the faulty NOx sensor.
• Repair or replace damaged wiring.
• Fix any exhaust leaks.
• OBD-II scanner
• Multimeter
• Socket set
$200 - $500
Moderate
• Volkswagen Passat
• Audi A4
• BMW 3 Series
• Regularly inspect the exhaust system.
• Ensure timely maintenance of emission control components.
• Use quality fuel to avoid sensor contamination.
Sensor Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if unsure.
• Regularly maintain the vehicle's emission system.
Check with the vehicle manufacturer for warranty coverage on emission components.
This code has become more common with the increased use of NOx sensors in modern vehicles to meet stringent emission standards.
Moderate – Should be addressed soon to ensure vehicle performance and emissions compliance.
Driving with a faulty NOx sensor can lead to increased emissions, which may be illegal in some areas.
• Engine at operating temperature
• Vehicle driven under varied conditions
The NOx sensor is typically located in the exhaust system, upstream of the catalytic converter on Bank 1.
Q: What is a NOx sensor?
A: A NOx sensor measures the levels of nitrogen oxides in the exhaust gases.
Q: Can I drive with a P24F4 code?
A: While the vehicle may still drive, it's important to fix the issue to avoid increased emissions and potential damage.
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Useful when diagnosis points toward damaged wiring, corroded terminals, or connector 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.