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 in your car that helps clean the exhaust is not opening like it should. It's like a door that's stuck shut, which can cause problems with keeping the air clean.
The reductant purge control valve is part of the system that reduces emissions by injecting a special fluid into the exhaust. If it's stuck closed, the fluid can't get into the exhaust system.
The P20A5 code indicates that the Engine Control Module (ECM) has detected that the reductant purge control valve 'A' is not opening as commanded. This valve is responsible for purging the reductant (Diesel Exhaust Fluid, or DEF) from the tank to the exhaust system. When the valve is stuck closed, it prevents the DEF from being delivered, leading to potential emission control failures.
• Check Engine Light is on
• Increased emissions
• Possible reduction in engine performance
• Faulty reductant purge control valve
• Electrical issues such as damaged wiring or connectors
• ECM malfunction
Reductant: A substance used to reduce emissions, commonly Diesel Exhaust Fluid (DEF).
ECM: Engine Control Module, the computer that controls engine functions.
• Use an OBD-II scanner to confirm the P20A5 code.
• Inspect the wiring and connectors to the reductant purge control valve for damage.
• Test the valve for proper operation using a multimeter or diagnostic tool.
• Replace the faulty reductant purge control valve.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $400
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 1500
• Regularly maintain the exhaust system.
• Check and replace the DEF fluid as needed.
• Inspect wiring and connectors for damage periodically.
Emission Control System Issue
• Have the vehicle inspected by a professional if the Check Engine Light is on.
• Avoid driving for extended periods with this code active to prevent further damage.
Check with your vehicle manufacturer for warranty coverage on emission control components.
The P20A5 code has become more common with the introduction of stricter emission standards and the use of DEF in diesel engines.
Moderate – It should be addressed soon to ensure proper vehicle operation and emissions compliance.
Driving with a malfunctioning emission control system may violate local emissions laws and can contribute to environmental pollution.
• Engine at operating temperature
• Vehicle in closed-loop mode
The reductant purge control valve is typically located near the DEF tank or along the exhaust system.
Q: Can I drive with a P20A5 code?
A: It's not recommended to drive for long periods with this code as it can lead to increased emissions and potential engine performance issues.
Q: What happens if I ignore the P20A5 code?
A: Ignoring this code can result in failing emissions tests and possible damage to the emission control system.
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