Engine-CodesGeneric – P20BB

P20BB Code - Reductant Heater 1 Control Circuit Low Voltage

Quick Answer

The P20BB diagnostic trouble code (DTC) refers to a Reductant Heater 1 Control Circuit Low Voltage issue. Common causes include Faulty reductant heater, Wiring or connector issues in the control circuit, Defective SCR system components. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P20BB indicates Reductant Heater 1 Control Circuit Low Voltage.
Common causes
Common causes include Faulty reductant heater, Wiring or connector issues in the control circuit, Defective SCR system components.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 06, 2024
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Code P20BB Description

The P20BB diagnostic trouble code (DTC) refers to a Reductant Heater 1 Control Circuit Low Voltage issue. The reductant heater is a component of the Selective Catalytic Reduction (SCR) system in diesel vehicles. The SCR system helps reduce harmful emissions by converting nitrogen oxides into nitrogen and water vapor. The reductant heater warms up the diesel exhaust fluid (DEF) to ensure optimal performance of the SCR system.

OBDII Code P20BB - Reductant Heater 1 Control Circuit Low Voltage
P20BB Code - Reductant Heater 1 Control Circuit Low Voltage

Common Causes of P20BB

  1. Faulty reductant heater
  2. Wiring or connector issues in the control circuit
  3. Defective SCR system components
  4. Corrosion or damage to electrical connections
  5. Faulty engine control module (ECM)

Symptoms of P20BB

  1. Check Engine light illuminated
  2. Decreased fuel efficiency
  3. Failed emissions test
  4. Reduced power output
  5. Increased emissions

How to Fix P20BB

  1. Diagnose the issue by using a scan tool to read the DTC and perform a visual inspection of the reductant heater and related components.
  2. Check the wiring and connectors for any signs of damage, corrosion, or loose connections.
  3. Test the reductant heater for proper operation and resistance values.
  4. Replace the reductant heater if it is found to be faulty, and repair or replace any damaged wiring or connectors.
  5. Clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P20BB

The cost of repairing a Reductant Heater 1 Control Circuit Low Voltage issue can vary depending on the specific cause of the problem and the labor rates in your area. Generally, the cost of parts for this repair can range from $200 to $500, while labor costs can range from $100 to $300. Overall, you can expect to pay anywhere from $300 to $800 for this repair. It's recommended to consult with a qualified mechanic to get an accurate estimate based on your vehicle's make and model.

Tech Notes for P20BB













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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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