Engine-CodesGeneric – P20BF

P20BF Code - Reductant Heater 2 Control Circuit Low Voltage

Quick Answer

The P20BF diagnostic trouble code (DTC) refers to the Reductant Heater 2 Control Circuit Low Voltage. Common causes include Faulty Heater: The reductant heater itself may be faulty, leading to low voltage in the control circuit, Wiring Issues: Damaged or corroded wiring can disrupt the flow of voltage to the reductant heater, triggering the P20BF code, Faulty Connectors: Loose or damaged connectors can also cause low voltage in the control circuit. 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
P20BF indicates Reductant Heater 2 Control Circuit Low Voltage.
Common causes
Common causes include Faulty Heater: The reductant heater itself may be faulty, leading to low voltage in the control circuit, Wiring Issues: Damaged or corroded wiring can disrupt the flow of voltage to the reductant heater, triggering the P20BF code, Faulty Connectors: Loose or damaged connectors can also cause low voltage in the control circuit.
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 11, 2024
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Code P20BF Description

The P20BF diagnostic trouble code (DTC) refers to the Reductant Heater 2 Control Circuit Low Voltage. This code indicates that there is an issue with the control circuit for the reductant heater, which is responsible for heating the diesel exhaust fluid (DEF) before it is injected into the exhaust stream to reduce emissions.

OBDII Code P20BF - Reductant Heater 2 Control Circuit Low Voltage
P20BF Code - Reductant Heater 2 Control Circuit Low Voltage

Common Causes of P20BF

  1. Faulty Heater: The reductant heater itself may be faulty, leading to low voltage in the control circuit.
  2. Wiring Issues: Damaged or corroded wiring can disrupt the flow of voltage to the reductant heater, triggering the P20BF code.
  3. Faulty Connectors: Loose or damaged connectors can also cause low voltage in the control circuit.
  4. ECM/PCM Malfunction: A malfunction in the engine control module (ECM) or powertrain control module (PCM) can also lead to the P20BF code.

Symptoms of P20BF

  1. Check Engine Light: The most common symptom of the P20BF code is the illumination of the check engine light on the vehicle's dashboard.
  2. Reduced Power: The vehicle may go into a reduced power mode to prevent further damage due to the low voltage in the reductant heater control circuit.
  3. Poor Fuel Economy: A decrease in fuel efficiency may be observed as a result of the vehicle compensating for the emission control system's inefficiency.
  4. Failed Emission Test: If the issue is not resolved, the vehicle may fail emission tests due to increased emissions.

How to Fix P20BF

  1. Diagnose the Issue: Use a scan tool to read the DTC and pinpoint the exact cause of the P20BF code.
  2. Inspect Wiring and Connectors: Check the wiring and connectors for any damage or corrosion, and repair or replace as necessary.
  3. Test the Reductant Heater: Test the reductant heater to ensure it is functioning properly and replace if faulty.
  4. Clear the Code: After making the necessary repairs, clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P20BF

The typical repair costs for addressing the P20BF code can vary depending on the root cause of the issue. On average, the parts for repairing the reductant heater control circuit can range from $200 to $500, while labor costs can range from $100 to $300. However, it's important to note that the specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It's advisable to check with local auto repair shops for a more accurate estimate.

Tech Notes for P20BF

























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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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