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 car's computer has detected a problem with the electrical circuit that controls a special injector that helps clean the car's exhaust. It's like a broken wire or switch in the system that helps reduce pollution.
The P20CB code indicates an issue with the control circuit for the exhaust aftertreatment fuel injector, which is responsible for injecting fuel into the exhaust system to help reduce emissions.
The exhaust aftertreatment fuel injector is part of the vehicle's emissions control system. It injects a small amount of fuel into the exhaust stream to help burn off excess pollutants. The P20CB code is triggered when the Engine Control Module (ECM) detects an open or malfunction in the control circuit of this injector.
• Check Engine Light is on
• Possible decrease in fuel efficiency
• Increased emissions
• Faulty exhaust aftertreatment fuel injector
• Open or shorted wiring in the injector circuit
• Faulty ECM
ECM: Engine Control Module
OBD-II: On-Board Diagnostics II
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the injector for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the exhaust aftertreatment fuel injector if faulty.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Chevrolet Silverado
• GMC Sierra
• Ford F-250
• Regular maintenance of the exhaust system.
• Ensure proper fuel quality.
• Regularly check for wiring damage.
Sensor Issue
• Address the issue promptly to avoid increased emissions.
• Consult a professional mechanic if unsure about repairs.
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
This code has become more common with the increased use of advanced emissions control systems.
Moderate – Addressing this issue is important to maintain emissions standards and vehicle efficiency.
Driving with this code may lead to increased emissions, which can be illegal in some areas.
• Vehicle at operating temperature
• Engine running
The exhaust aftertreatment fuel injector is located in the exhaust system, typically near the catalytic converter.
Q: Can I drive with a P20CB code?
A: It's possible to drive with this code, but it's not recommended due to increased emissions and potential damage to the emissions system.
Q: How can I clear the P20CB code?
A: The code can be cleared with an OBD-II scanner, but the underlying issue should be fixed to prevent it from returning.
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Universal · Digital multimeter
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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.