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 part of your car's system that helps reduce pollution is getting too hot. It's like when a stove gets too hot and you need to turn it down.
The Selective Catalytic Reduction (SCR) system is overheating on the side of the engine known as Bank 2.
The P20F0 code indicates that the SCR NOx catalyst on Bank 2 has exceeded its normal operating temperature. The SCR system is responsible for reducing nitrogen oxide emissions in diesel engines by injecting a urea-based fluid (DEF) into the exhaust stream. Overheating can be caused by excessive DEF injection, exhaust leaks, or a malfunctioning temperature sensor.
• Check engine light is on
• Reduced engine performance
• Increased emissions
• Excessive DEF injection
• Exhaust leaks
• Faulty temperature sensor
SCR: Selective Catalytic Reduction
NOx: Nitrogen Oxides
DEF: Diesel Exhaust Fluid
• Check for any exhaust leaks in the system.
• Inspect the DEF injection system for proper operation.
• Test the temperature sensor for accurate readings.
• Repair any identified exhaust leaks.
• Replace or repair the DEF injector if malfunctioning.
• Replace the temperature sensor if faulty.
• OBD-II scanner
• Temperature sensor tester
• Wrench set
$200 - $600
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 2500
• Regularly check the DEF fluid levels.
• Ensure proper maintenance of the exhaust system.
• Monitor the engine's performance for any irregularities.
Emission Control System Issue
• Avoid driving the vehicle aggressively until repaired.
• Schedule a service appointment as soon as possible.
Check with your vehicle manufacturer for specific warranty coverage related to emissions systems.
This code has become more common with the increased use of SCR systems in diesel engines to meet stricter emission standards.
Moderate – While the vehicle can still be driven, it should be addressed soon to prevent potential damage to the SCR system.
Driving with a malfunctioning emissions system may violate emissions regulations and contribute to air pollution.
• Engine at operating temperature
• Vehicle in a controlled environment
The SCR NOx catalyst is located in the exhaust system, typically near the exhaust manifold on the side of the engine known as Bank 2.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to increased emissions and potential damage to the SCR system, which may result in more costly repairs.
Q: Can I drive my car with this code?
A: While you can drive the vehicle, it is recommended to get it checked soon to prevent further issues.
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Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
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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.