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's a problem with the heater in the system that helps reduce pollution from your car. It's like a small heater isn't working right, and it's important because it helps keep the air cleaner.
The P20C7 code is triggered when the Engine Control Module (ECM) detects a low voltage condition in the control circuit for the reductant heater D. This heater is part of the diesel exhaust fluid system that helps reduce emissions.
The reductant heater is used to ensure that the diesel exhaust fluid (DEF) remains at the correct temperature for effective operation. A low voltage condition in the control circuit indicates a potential issue with the wiring, connectors, or the heater itself, which can affect the DEF system's ability to reduce NOx emissions.
• Check Engine Light illuminated
• Reduced engine performance
• Possible increase in emissions
• Faulty reductant heater D
• Open or shorted wiring in the heater circuit
• Poor electrical connection at the heater or ECM
Reductant: A substance used to reduce emissions, commonly diesel exhaust fluid (DEF).
Heater: A device used to maintain the temperature of the reductant for optimal performance.
• Use a scan tool to verify the code and check for other related codes.
• Inspect the reductant heater D wiring and connectors for damage or corrosion.
• Test the heater circuit for proper voltage and continuity.
• Repair or replace damaged wiring and connectors.
• Replace the reductant heater D if it is faulty.
• Clear the codes and test drive to ensure the issue is resolved.
• OBD-II scan tool
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Ram 2500
• Regularly inspect and maintain the DEF system.
• Ensure proper DEF fluid levels and quality.
• Perform periodic electrical system checks.
Sensor Issue
• Have your vehicle inspected by a professional mechanic.
• Avoid ignoring the Check Engine Light, as it can lead to more severe issues.
Check your vehicle's warranty for coverage on emissions-related components.
This code typically appears in diesel vehicles equipped with DEF systems to meet emissions standards.
Moderate – Addressing this issue promptly is important to maintain emissions compliance and vehicle performance.
Operating a vehicle with emissions system faults may not comply with local regulations and can contribute to environmental pollution.
• Engine running
• DEF system active
The reductant heater D is typically located near the DEF tank or lines, depending on the vehicle model.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to increased emissions and potential engine performance issues.
Q: Can I drive my car with this code?
A: While you may be able to drive, it's best to address the issue soon to avoid emissions problems and potential engine damage.
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