Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car has a special heater that helps clean the exhaust. This code means that one of these heaters isn't using enough power to work right.
The reductant heater is part of the system that reduces harmful emissions from the exhaust. A low current indicates that the heater isn't operating as expected.
The P221E code is triggered when the Engine Control Module (ECM) detects that the current in the reductant heater circuit C is below the expected range. This can affect the efficiency of the Selective Catalytic Reduction (SCR) system, which uses Diesel Exhaust Fluid (DEF) to reduce nitrogen oxide emissions.
• Check Engine Light is on
• Reduced engine performance
• Increased emissions
• Faulty reductant heater
• Damaged wiring or connectors
• Faulty ECM
Reductant: A substance used to reduce emissions, often Diesel Exhaust Fluid (DEF) in diesel engines.
SCR: Selective Catalytic Reduction, a system that reduces nitrogen oxide emissions.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage.
• Test the reductant heater for proper operation.
• Replace the faulty reductant heater.
• Repair or replace damaged wiring or connectors.
• Replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 2500
• Regular maintenance checks
• Ensure DEF system is functioning properly
• Inspect wiring periodically
Sensor Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if unsure.
• Regularly check the DEF system.
Check with the vehicle manufacturer for specific warranty coverage on emissions-related components.
This code is part of the emissions control system and has been more common in diesel vehicles since the introduction of stricter emissions standards.
Moderate – Addressing this issue promptly can prevent further emissions system damage.
Driving with a malfunctioning emissions system can lead to increased pollution and may not comply with local emissions laws.
• Engine at operating temperature
• DEF system active
The reductant heater is typically located near the DEF tank or along the DEF delivery lines.
Q: Can I drive with the P221E code?
A: It's possible, but not recommended as it may lead to increased emissions and further damage.
Q: How do I reset the P221E code?
A: After repairs, use an OBD-II scanner to clear the code. If the issue persists, the code will return.
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