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 the part of the car that heats up a special liquid used to clean the exhaust. It's like when a heater in your house doesn't work right.
The P20C6 code indicates that the control circuit for the reductant heater D is not performing as expected, which could affect the heating of the diesel exhaust fluid (DEF).
The reductant heater is part of the Selective Catalytic Reduction (SCR) system in diesel engines. It ensures that the DEF stays at the right temperature to function properly. If the control circuit for heater D is not working correctly, it could lead to improper DEF heating, affecting emissions control.
• Check engine light on
• Poor fuel efficiency
• Increased emissions
• Faulty reductant heater D
• Wiring issues in the heater circuit
• Faulty control module
Reductant: A substance used to reduce pollutants in exhaust gases.
SCR: Selective Catalytic Reduction, a system that reduces emissions in diesel engines.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage.
• Test the reductant heater D for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the reductant heater D if faulty.
• Reset the OBD-II codes and test drive the vehicle.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $500
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Dodge Ram 2500
• Regularly inspect the SCR system.
• Ensure proper DEF levels are maintained.
• Perform routine vehicle maintenance.
Sensor Issue
• Take your vehicle to a professional mechanic.
• Do not ignore the check engine light.
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
This code has been more common in vehicles with higher mileage or those that frequently operate in cold climates.
Moderate – Addressing this issue helps maintain emissions control and vehicle efficiency.
Driving with a malfunctioning emissions system may violate emissions regulations.
• Engine at operating temperature
• Vehicle in a safe, stationary position
The reductant heater is typically located near the DEF tank or along the DEF delivery lines.
Q: Can I drive with a P20C6 code?
A: It's possible, but not recommended. It may lead to increased emissions and reduced fuel efficiency.
Q: How do I reset the check engine light after repairs?
A: Use an OBD-II scanner to clear the codes after confirming the issue is resolved.
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