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P20BB 2017 GMC Sierra Code - Reductant Heater 1 Control Circuit Low Voltage

Quick Answer

The P20BB diagnostic trouble code (DTC) for a 2017 GMC Sierra relates to the Reductant Heater 1 Control Circuit Low Voltage. Common causes include Faulty reductant heater element, Damaged wiring or connectors in the control circuit, Malfunctioning control module. 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 2017 GMC Sierra indicates Reductant Heater 1 Control Circuit Low Voltage.
Common causes
Common causes include Faulty reductant heater element, Damaged wiring or connectors in the control circuit, Malfunctioning control module.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 16, 2024
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Code P20BB 2017 GMC Sierra Description

The P20BB diagnostic trouble code (DTC) for a 2017 GMC Sierra relates to the Reductant Heater 1 Control Circuit Low Voltage. This code indicates that there is an issue with the control circuit for the reductant heater, which is a crucial component of the selective catalytic reduction (SCR) system in modern diesel vehicles. The reductant heater is responsible for heating the diesel exhaust fluid (DEF) before it enters the SCR catalyst to facilitate the reduction of harmful nitrogen oxides (NOx) into nitrogen and water vapor.

OBDII Code P20BB 2017 GMC Sierra - Reductant Heater 1 Control Circuit Low Voltage
P20BB 2017 GMC Sierra Code - Reductant Heater 1 Control Circuit Low Voltage

Common Causes of P20BB 2017 GMC Sierra

  1. Faulty reductant heater element
  2. Damaged wiring or connectors in the control circuit
  3. Malfunctioning control module
  4. Low DEF quality or contamination
  5. Electrical issues such as blown fuses or relays

Symptoms of P20BB 2017 GMC Sierra

  1. Check engine light illuminated
  2. Reduced fuel economy
  3. Decreased engine performance
  4. Failed emissions test
  5. Increased DEF consumption

How to Fix P20BB 2017 GMC Sierra

  1. Diagnose the specific cause of the low voltage issue in the reductant heater circuit using a scan tool and multimeter.
  2. Inspect the wiring and connectors for any damage or corrosion, repairing or replacing as necessary.
  3. Test the reductant heater element for proper resistance and functionality, replacing if faulty.
  4. Check the control module for any signs of malfunction, reprogramming or replacing if needed.
  5. Clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P20BB 2017 GMC Sierra

The typical repair costs for addressing a P20BB code on a 2017 GMC Sierra can range from $200 to $600, depending on the specific cause of the issue and the cost of parts and labor. It's important to note that diagnosis time and labor rates at auto repair shops can vary, with hourly rates typically ranging between $80 and $150. Factors such as location, vehicle make and model, and engine type can also influence repair costs. For a more accurate estimate, it's recommended to consult with local auto repair shops.

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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.

Frequently Asked Questions about P20BB 2017 GMC Sierra Code

1. What are the common symptoms of OBDII code P20BB in a 2017 GMC Sierra?

- Common symptoms include the check engine light coming on, reduced engine performance, and potential issues with the exhaust system.

2. What does the OBDII code P20BB for a 2017 GMC Sierra indicate?

- The code P20BB indicates a problem with the Reductant Heater 1 Control Circuit Low Voltage in the vehicle's selective catalytic reduction (SCR) system.

3. What are the possible causes of OBDII code P20BB in a 2017 GMC Sierra?

- Possible causes include a faulty reductant heater, damaged wiring or connectors, a defective SCR control module, or issues with the power supply to the reductant heater.

4. How can I diagnose the OBDII code P20BB in my 2017 GMC Sierra?

- Diagnosis typically involves using a scan tool to retrieve the code, checking the system for any visible damage or loose connections, and testing the components involved in the reductant heater system.

5. Can I continue driving my 2017 GMC Sierra with the OBDII code P20BB?

- It is not recommended to continue driving with the code active, as it can lead to increased emissions, reduced fuel efficiency, and potential damage to the engine or emissions system.

6. How do I repair OBDII code P20BB in a 2017 GMC Sierra?

- Repair may involve replacing the reductant heater, repairing or replacing damaged wiring or connectors, resetting the code, and performing a thorough inspection of the SCR system.

7. Is it possible to reset the OBDII code P20BB in a 2017 GMC Sierra without repairing the issue?

- While you can clear the code with a scan tool, it is important to address the underlying problem causing the code to prevent further issues down the line.

8. Can a DIY enthusiast fix the OBDII code P20BB in a 2017 GMC Sierra?

- Depending on your level of automotive expertise, you may be able to diagnose and repair the issue yourself, but it is recommended to consult a professional mechanic for accurate diagnosis and repair.

9. How long does it typically take to repair OBDII code P20BB in a 2017 GMC Sierra?

- The repair time can vary based on the exact cause of the code, but it may take a few hours to a full day to diagnose and repair the issue properly.

10. Are there any preventive measures to avoid OBDII code P20BB in a 2017 GMC Sierra?

- Regular maintenance checks, such as inspecting the SCR system components and ensuring proper operation, can help prevent issues that may trigger the code P20BB.

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