Engine-Codes.com
Engine-Codes – GMC – P20BC 2016 GMC Sierra

P20BC 2016 GMC Sierra Code - Reductant Heater 1 Control Circuit High Voltage

Quick Answer

The P20BC diagnostic trouble code (DTC) for a 2016 GMC Sierra relates to the Reductant Heater 1 Control Circuit High Voltage. Common causes include Faulty Reductant Heater: The most common cause of the P20BC code is a malfunctioning reductant heater that is drawing excessive voltage, Wiring Issues: Corrosion, fraying, or short circuits in the wiring connected to the reductant heater can cause high voltage readings, Faulty Control Module: A defective control module responsible for managing the reductant heater operation can also trigger the P20BC code. 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
P20BC 2016 GMC Sierra indicates Reductant Heater 1 Control Circuit High Voltage.
Common causes
Common causes include Faulty Reductant Heater: The most common cause of the P20BC code is a malfunctioning reductant heater that is drawing excessive voltage, Wiring Issues: Corrosion, fraying, or short circuits in the wiring connected to the reductant heater can cause high voltage readings, Faulty Control Module: A defective control module responsible for managing the reductant heater operation can also trigger the P20BC code.
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 10, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P20BC 2016 GMC Sierra Description

The P20BC diagnostic trouble code (DTC) for a 2016 GMC Sierra relates to the Reductant Heater 1 Control Circuit High Voltage. In modern diesel vehicles, a reductant heater is used to warm up the Diesel Exhaust Fluid (DEF) to prevent freezing in cold weather conditions. The DEF is injected into the exhaust stream to reduce nitrogen oxide emissions, an essential part of the vehicle's emissions control system. The reductant heater control circuit is responsible for managing the heater's operation and ensuring it functions correctly.

OBDII Code P20BC 2016 GMC Sierra - Reductant Heater 1 Control Circuit High Voltage
P20BC 2016 GMC Sierra Code - Reductant Heater 1 Control Circuit High Voltage

Common Causes of P20BC 2016 GMC Sierra

  1. Faulty Reductant Heater: The most common cause of the P20BC code is a malfunctioning reductant heater that is drawing excessive voltage.
  2. Wiring Issues: Corrosion, fraying, or short circuits in the wiring connected to the reductant heater can cause high voltage readings.
  3. Faulty Control Module: A defective control module responsible for managing the reductant heater operation can also trigger the P20BC code.
  4. Software Glitch: Occasionally, a software glitch in the vehicle's engine control module (ECM) can incorrectly interpret voltage readings, leading to the code.
  5. Environmental Factors: Extreme temperatures or exposure to moisture can also affect the reductant heater's performance and trigger the code.

Symptoms of P20BC 2016 GMC Sierra

  1. Check Engine Light: The most common symptom associated with the P20BC code is the illumination of the check engine light on the vehicle's dashboard.
  2. Reduced Engine Power: The vehicle may go into a reduced power mode to protect the engine from further damage, resulting in decreased performance.
  3. Poor Fuel Efficiency: A malfunctioning reductant heater can lead to poor fuel efficiency as the emissions control system may not be operating optimally.
  4. Increased Emissions: High voltage in the reductant heater control circuit can lead to increased emissions output, potentially causing the vehicle to fail emissions tests.

How to Fix P20BC 2016 GMC Sierra

  1. Diagnose the Issue: Use a diagnostic scanner to retrieve the trouble code and perform a thorough inspection of the reductant heater, wiring, and control module to pinpoint the exact cause.
  2. Repair or Replace Reductant Heater: If the heater is faulty, it may need to be repaired or replaced to resolve the high voltage issue.
  3. Check and Repair Wiring: Inspect the wiring connected to the reductant heater for any damage or corrosion, repairing or replacing as necessary.
  4. Test Control Module: Test the control module to ensure it is functioning correctly, replacing it if deemed faulty.
  5. Clear Codes and Test Drive: After making the necessary repairs, clear the trouble codes from the ECM and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P20BC 2016 GMC Sierra

The cost of repairing a P20BC code on a 2016 GMC Sierra can vary depending on the specific cause of the issue and the labor rates at the auto repair shop. Typically, the cost of replacing a reductant heater can range from $200 to $500, while diagnosing and repairing wiring issues may cost between $100 and $300. If the control module needs to be replaced, it can add an additional $150 to $400 to the repair bill. Overall, the total repair costs for addressing a P20BC code can range from $300 to $1200, including parts and labor. It is advisable to consult with a professional mechanic to get an accurate estimate for your specific vehicle. Keep in mind that labor rates can vary based on location, vehicle make and model, and the expertise of the repair shop.

Need more information about the P20BC 2016 GMC Sierra code?

Need more information on how to fix the P20BC 2016 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P20BC 2016 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 P20BC 2016 GMC Sierra Code

1. What are the common symptoms of OBDII code P20BC in a 2016 GMC Sierra?

The common symptoms of OBDII code P20BC in a 2016 GMC Sierra include the check engine light coming on, decreased fuel efficiency, and potential issues with the vehicle's exhaust system.

2. What does the OBDII code P20BC indicating "Reductant Heater 1 Control Circuit High Voltage" mean?

The OBDII code P20BC indicates that there is a high voltage condition detected in the control circuit of Reductant Heater 1 in the vehicle's selective catalytic reduction (SCR) system.

3. What are the possible causes of OBDII code P20BC in a 2016 GMC Sierra?

Possible causes of OBDII code P20BC in a 2016 GMC Sierra include a faulty reductant heater, damaged wiring or connectors in the heater circuit, a defective heater control module, or issues with the vehicle's powertrain control module (PCM).

4. How serious is OBDII code P20BC in a 2016 GMC Sierra?

OBDII code P20BC should be addressed promptly to ensure the proper functioning of the vehicle's SCR system and to prevent potential damage to the catalytic converter. Ignoring this code may lead to decreased engine performance and increased emissions.

5. What are some diagnostic steps to troubleshoot OBDII code P20BC in a 2016 GMC Sierra?

Diagnostic steps to troubleshoot OBDII code P20BC may include checking the reductant heater for proper operation, inspecting the wiring and connectors for damage, testing the heater control module, and scanning the vehicle's PCM for any related fault codes.

6. Can OBDII code P20BC be repaired without professional help?

While some DIY enthusiasts may attempt to address OBDII code P20BC on their own, it is recommended to seek professional assistance, especially when dealing with complex emissions control systems like the SCR system in a 2016 GMC Sierra.

7. How much does it typically cost to repair OBDII code P20BC in a 2016 GMC Sierra?

The cost of repairing OBDII code P20BC in a 2016 GMC Sierra can vary depending on the underlying cause of the issue. It is advisable to consult a mechanic or dealership to get an accurate estimate for the repair.

8. Can driving with OBDII code P20BC in a 2016 GMC Sierra cause further damage?

Continued driving with OBDII code P20BC in a 2016 GMC Sierra can potentially cause damage to the vehicle's catalytic converter and result in increased emissions. It is best to address the issue promptly to prevent further complications.

9. How long does it take to repair OBDII code P20BC in a 2016 GMC Sierra?

The repair time for OBDII code P20BC in a 2016 GMC Sierra can vary depending on the specific cause of the issue and the availability of parts. In some cases, the repair may be completed within a few hours, while more complex issues may require additional time.

10. Are there any preventive measures to avoid OBDII code P20BC in a 2016 GMC Sierra?

To prevent OBDII code P20BC in a 2016 GMC Sierra, it is essential to follow the manufacturer's recommended maintenance schedule, use high-quality diesel exhaust fluid (DEF), and address any warning lights or unusual symptoms promptly to avoid potential SCR system issues.

Discuss the causes and fixes for P20BC 2016 GMC Sierra OBDII Code

Submit a New Comment

Code P20BC 2016 GMC Sierra comments

No comments found for this page.