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 valve that helps clean the exhaust. It's not working properly because the signal is too low.
The reductant purge control valve is part of the system that injects a special fluid into the exhaust to reduce pollution. A 'circuit low' code indicates that the electrical signal from the valve is lower than expected.
The P20A2 code is triggered when the Engine Control Module (ECM) detects a low voltage condition in the Reductant Purge Control Valve A circuit. This valve is responsible for purging the reductant system, which is used to reduce NOx emissions in diesel engines by injecting a urea-based fluid into the exhaust stream.
• Check Engine Light is on
• Possible reduction in engine performance
• Increased emissions
• Faulty reductant purge control valve
• Wiring issues or poor connections in the valve circuit
• Faulty ECM
ECM: Engine Control Module, the computer that controls engine functions.
SCR: Selective Catalytic Reduction, a system that reduces NOx emissions in diesel engines.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the voltage and ground at the reductant purge control valve.
• Repair or replace damaged wiring or connectors.
• Replace the reductant purge control valve if faulty.
• Clear the code and test drive to ensure the issue is resolved.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Ram 2500
• Regularly inspect and maintain the reductant system.
• Ensure all electrical connections are clean and secure.
• Use high-quality DEF (Diesel Exhaust Fluid).
Sensor Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if unsure.
• Regularly maintain the exhaust system.
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
This code has become more common with the increased use of diesel engines equipped with SCR (Selective Catalytic Reduction) systems.
Moderate – Addressing this issue in a timely manner can prevent further emissions problems.
Ignoring emissions-related issues can lead to failing emissions tests and possible fines.
• Engine running at normal operating temperature
• Vehicle in closed-loop operation
The reductant purge control valve is typically located near the diesel exhaust fluid tank or along the reductant line.
Q: Can I drive with a P20A2 code?
A: While you may be able to drive, it's best to address the issue soon to avoid increased emissions and potential engine performance issues.
Q: What is a reductant purge control valve?
A: It's a valve that helps manage the flow of diesel exhaust fluid into the exhaust system to reduce emissions.
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