Engine-CodesGMC – P20C0 2018 GMC Sierra

P20C0 2018 GMC Sierra Code - Reductant Heater 2 Control Circuit High Voltage

Quick Answer

The P20C0 diagnostic trouble code (DTC) for a 2018 GMC Sierra refers to the Reductant Heater 2 Control Circuit High Voltage. Common causes include Wiring harness damage or corrosion, Faulty reductant heater element, Defective temperature sensor. 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
P20C0 2018 GMC Sierra indicates Reductant Heater 2 Control Circuit High Voltage.
Common causes
Common causes include Wiring harness damage or corrosion, Faulty reductant heater element, Defective temperature sensor.
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 18, 2024
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Code P20C0 2018 GMC Sierra Description

The P20C0 diagnostic trouble code (DTC) for a 2018 GMC Sierra refers to the Reductant Heater 2 Control Circuit High Voltage. This code indicates that there is an issue with the control circuit for the reductant heater 2, which is a component of the selective catalytic reduction (SCR) system in the vehicle. The reductant heater is responsible for heating the diesel exhaust fluid (DEF) before it is injected into the exhaust stream to reduce harmful emissions.

OBDII Code P20C0 2018 GMC Sierra - Reductant Heater 2 Control Circuit High Voltage
P20C0 2018 GMC Sierra Code - Reductant Heater 2 Control Circuit High Voltage

Common Causes of P20C0 2018 GMC Sierra

  1. Wiring harness damage or corrosion
  2. Faulty reductant heater element
  3. Defective temperature sensor
  4. Power supply issues
  5. Software glitches in the SCR system

Symptoms of P20C0 2018 GMC Sierra

  1. Check engine light illuminated
  2. Decreased fuel efficiency
  3. Failed emissions test
  4. Limp mode activation
  5. Strange smells from the exhaust

How to Fix P20C0 2018 GMC Sierra

  1. Perform a thorough inspection of the reductant heater 2 control circuit, wiring, and connections.
  2. Test the reductant heater element and temperature sensor for proper functionality.
  3. Check the power supply to the reductant heater for voltage irregularities.
  4. Replace any damaged wiring, faulty components, or sensors as needed.
  5. Clear the DTC and reset the system to ensure the issue has been resolved.

Cost to Fix P20C0 2018 GMC Sierra

The typical repair costs for addressing a P20C0 code on a 2018 GMC Sierra can range from $200 to $600, depending on the specific cause of the issue and the cost of parts and labor in your area. It's important to note that diagnostic time and labor rates at auto repair shops can vary, so it's advisable to obtain quotes from multiple sources to get an accurate estimate. Keep in mind that rates may be higher at dealerships or in metropolitan areas, while independent shops may offer more competitive pricing.

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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 P20C0 2018 GMC Sierra Code

What does OBDII code P20C0 mean for a 2018 GMC Sierra?

Code P20C0 indicates a high voltage issue in the Reductant Heater 2 Control Circuit, which is part of the diesel exhaust fluid (DEF) system.

What are common symptoms of code P20C0 in a 2018 GMC Sierra?

Symptoms may include the check engine light turning on, DEF system warnings, reduced engine power, and difficulty maintaining proper DEF temperature.

What causes code P20C0 in a 2018 GMC Sierra?

Common causes include a faulty reductant heater, damaged wiring or connectors in the circuit, or a malfunctioning control module.

Can code P20C0 affect vehicle performance?

Yes, this code can lead to reduced engine performance and prevent the DEF system from functioning properly, potentially causing emissions issues.

How is code P20C0 diagnosed in a 2018 GMC Sierra?

Technicians typically use a scan tool to check for related codes, inspect the wiring and connectors, and test the reductant heater's electrical resistance and voltage.

Can I still drive my 2018 GMC Sierra with code P20C0?

Driving with this code is possible but not recommended, as it may lead to reduced engine performance and increased emissions over time.

How do you fix code P20C0 in a 2018 GMC Sierra?

Repairs may involve replacing the reductant heater, repairing damaged wiring or connectors, or reprogramming the control module if necessary.

How much does it cost to repair code P20C0?

Repair costs can vary widely, but replacing the reductant heater typically costs between $200 and $500, depending on parts and labor.

Can weather conditions cause code P20C0?

Cold weather can sometimes exacerbate issues with the reductant heater, especially if the DEF system struggles to maintain proper temperature.

Is code P20C0 a common issue in GMC Sierra trucks?

It’s not uncommon for diesel trucks like the GMC Sierra to experience reductant heater-related codes, especially in colder climates or as the vehicle ages.

Discuss the causes and fixes for P20C0 2018 GMC Sierra OBDII Code

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