Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there is a problem with the heater that warms up a special liquid used to clean the car's exhaust. It's like when a heater in your house stops working and can't warm up the room.
The P20BB code indicates that the control circuit for the reductant heater, which helps keep the diesel exhaust fluid (DEF) at the right temperature, is experiencing low voltage or is not working properly.
The reductant heater is part of the Selective Catalytic Reduction (SCR) system in diesel engines. It ensures that the DEF does not freeze in cold temperatures by maintaining it at an optimal temperature. When the control circuit for this heater has low voltage, it means the heater may not be functioning properly, which can affect the efficiency of the SCR system.
• Check Engine Light illuminated
• Poor emissions performance
• Reduced fuel efficiency
• Faulty reductant heater
• Damaged wiring or connectors
• Faulty control module
Reductant: A substance used to reduce pollutants in the exhaust system.
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 for proper operation.
• Replace the faulty reductant heater.
• Repair or replace damaged wiring or connectors.
• Replace the control module if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Ram 2500
• Regularly inspect the SCR system components.
• Ensure proper maintenance of the vehicle's electrical system.
• Use high-quality DEF fluid.
Sensor Issue
• Have the vehicle inspected by a professional if the Check Engine Light is on.
• Avoid driving in extremely cold conditions until the issue is resolved.
Check if the vehicle's emissions system warranty covers the reductant heater.
This code has been more prevalent in colder climates where DEF freezing is a common issue.
Moderate – Addressing this issue is important to maintain emissions standards and vehicle performance.
Ignoring emissions-related issues can lead to failing emissions tests and potential fines.
• Vehicle at operating temperature
• Cold ambient temperatures
The reductant heater is typically located near the DEF tank or lines.
Q: Can I drive with a P20BB code?
A: It's possible to drive, but it's not recommended as it can affect emissions and vehicle performance.
Q: What happens if I ignore this code?
A: Ignoring the code can lead to increased emissions and potential damage to the SCR system.
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