Engine-CodesChevrolet – P20C4 Chevrolet

P20C4 Chevrolet Code - Reductant Heater 'C' Control Circuit High

Quick Answer

The P20C4 diagnostic trouble code for Chevrolet vehicles refers to a fault in the Reductant Heater 'C' Control Circuit, specifically indicating a high voltage condition. Common causes include Faulty reductant heater 'C' control module, Damaged wiring or connectors in the control circuit, Short circuit in the heater element. 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
P20C4 Chevrolet indicates Reductant Heater 'C' Control Circuit High.
Common causes
Common causes include Faulty reductant heater 'C' control module, Damaged wiring or connectors in the control circuit, Short circuit in the heater element.
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 09, 2024
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Code P20C4 Chevrolet Description

The P20C4 diagnostic trouble code for Chevrolet vehicles refers to a fault in the Reductant Heater 'C' Control Circuit, specifically indicating a high voltage condition. The reductant heater is a crucial component of the selective catalytic reduction (SCR) system, which helps reduce harmful emissions in diesel engines by converting nitrogen oxides (NOx) into nitrogen and water vapor.

OBDII Code P20C4 Chevrolet - Reductant Heater 'C' Control Circuit High
P20C4 Chevrolet Code - Reductant Heater 'C' Control Circuit High

Common Causes of P20C4 Chevrolet

  1. Faulty reductant heater 'C' control module
  2. Damaged wiring or connectors in the control circuit
  3. Short circuit in the heater element
  4. Malfunctioning temperature sensor
  5. Corrosion or physical damage to components in the SCR system

Symptoms of P20C4 Chevrolet

  1. Illumination of the check engine light
  2. Reduced fuel efficiency
  3. Decreased performance or power output
  4. Increased emissions output
  5. Erratic or rough engine idling

How to Fix P20C4 Chevrolet

  1. Diagnose the specific cause of the high voltage condition in the reductant heater 'C' control circuit using a diagnostic scanner.
  2. Inspect the wiring, connectors, and heater element for any visible damage or signs of wear.
  3. Test the reductant heater 'C' control module and temperature sensor for proper functionality.
  4. Replace any faulty components identified during the diagnostic process.
  5. Clear the diagnostic trouble codes and perform a test drive to ensure the issue has been resolved.

Cost to Fix P20C4 Chevrolet

The typical repair costs for addressing a P20C4 diagnostic trouble code can vary depending on the specific cause of the issue and the required repairs. In general, replacing faulty components in the reductant heater 'C' control circuit, such as the control module or heater element, can range from $200 to $500 in parts and labor. However, it's important to note that diagnosis time and labor rates at auto repair shops can vary, with hourly rates typically ranging from $80 to $150. Additionally, rates may be higher at dealerships or in metropolitan areas, while independent shops may offer lower prices. To get a more accurate estimate, it's advisable 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.

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