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 the system in your car that helps reduce pollution isn't working as well as it should on one side of the engine.
The Selective Catalytic Reduction (SCR) system is not reducing nitrogen oxides (NOx) emissions efficiently on Bank 2.
P20F2 indicates that the SCR system, which reduces NOx emissions by injecting a urea-based solution into the exhaust stream, is not performing efficiently on Bank 2. This can result from a malfunctioning catalyst, injector, or other components in the SCR system.
• Check Engine Light (CEL) is on
• Increased NOx emissions
• Possible reduction in engine performance
• Faulty SCR catalyst
• Defective NOx sensor
• Issues with the urea injector
SCR: Selective Catalytic Reduction, a technology used to reduce NOx emissions.
NOx: Nitrogen oxides, harmful pollutants produced by combustion engines.
• Check for other related codes
• Inspect the SCR catalyst for damage
• Test NOx sensors and urea injectors
• Replace faulty SCR catalyst
• Replace or clean NOx sensors
• Repair or replace urea injector
• OBD-II scanner
• Multimeter
• NOx sensor tester
$500 - $2000
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 2500
• Regular maintenance of the exhaust system
• Use high-quality DEF (Diesel Exhaust Fluid)
• Regularly inspect NOx sensors
Emissions Control
• Take your vehicle to a professional mechanic
• Avoid driving extensively until the issue is fixed
Check with your vehicle manufacturer for emissions-related warranty coverage.
This code has become more common with the increased use of SCR systems in diesel vehicles to meet emissions standards.
Moderate – Addressing this issue is important to maintain emissions compliance and vehicle performance.
Driving with this issue may result in failing emissions tests and increased pollution.
• Engine at operating temperature
• Vehicle driven under normal conditions
The SCR catalyst is located in the exhaust system, typically downstream of the turbocharger.
Q: What is an SCR system?
A: SCR stands for Selective Catalytic Reduction, a system that reduces NOx emissions in diesel engines.
Q: Can I drive with a P20F2 code?
A: It's not recommended to drive extensively with this code, as it can lead to increased emissions and potential engine performance issues.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
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.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.
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.