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 there is a problem with a part of the car that helps clean up the exhaust gases. It's like a special sprayer that isn't working right.
The P20D1 code indicates an issue with the control circuit for the exhaust aftertreatment fuel injector labeled 'B'. This injector is responsible for injecting fuel into the exhaust system to help reduce emissions.
The Exhaust Aftertreatment Fuel Injector B is part of the Selective Catalytic Reduction (SCR) system, which reduces harmful emissions. The control circuit for this injector is either open or not functioning correctly, which can lead to increased emissions and possibly affect engine performance.
• Check Engine Light is on
• Increased exhaust emissions
• Possible decrease in fuel efficiency
• Faulty Exhaust Aftertreatment Fuel Injector B
• Open or shorted wiring in the injector circuit
• Faulty Engine Control Module (ECM)
OBD-II: On-Board Diagnostics II, a standardized system for self-diagnostics in vehicles.
SCR: Selective Catalytic Reduction, a system used to reduce emissions in diesel engines.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for the injector.
• Test the injector for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the faulty injector.
• Reprogram or replace the ECM if necessary.
• OBD-II Scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 2500
• Regular maintenance of the exhaust system.
• Ensure quality fuel is used.
• Regularly inspect wiring for damage.
Sensor Issue
• Do not ignore the check engine light.
• Have the vehicle inspected by a professional.
• Avoid driving long distances until the issue is resolved.
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
This code has been associated with issues in vehicles equipped with SCR systems, particularly in diesel engines.
Moderate – It should be addressed soon to avoid increased emissions and potential engine issues.
Driving with a malfunctioning emissions system may violate emissions laws and can lead to fines.
• Engine running
• Vehicle at operating temperature
The Exhaust Aftertreatment Fuel Injector B is typically located in the exhaust system near the catalytic converter.
Q: Can I drive with a P20D1 code?
A: It's not recommended to drive for long periods with this code active, as it can lead to increased emissions and potential engine damage.
Q: How can I prevent this code from appearing?
A: Regular maintenance and using quality fuel can help prevent issues with the exhaust aftertreatment system.
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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.
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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.