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P20E4 GMC Code - Exhaust Gas Temperature Sensor 2/3 Correlation Bank 1

Quick Answer

The P20E4 diagnostic trouble code (DTC) indicates a correlation issue between Exhaust Gas Temperature Sensor 2 and Exhaust Gas Temperature Sensor 3 on Bank 1 of the vehicle's engine. Common causes include Faulty Sensors: The most common cause of this code is a malfunctioning Exhaust Gas Temperature Sensor 2 or Sensor 3, Wiring Issues: Corrosion, damage, or poor connections in the wiring harness connected to the sensors can also trigger this code, Exhaust System Leaks: Leaks in the exhaust system, near the sensors, can lead to incorrect temperature readings and trigger the 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
P20E4 GMC indicates Exhaust Gas Temperature Sensor 2/3 Correlation Bank 1.
Common causes
Common causes include Faulty Sensors: The most common cause of this code is a malfunctioning Exhaust Gas Temperature Sensor 2 or Sensor 3, Wiring Issues: Corrosion, damage, or poor connections in the wiring harness connected to the sensors can also trigger this code, Exhaust System Leaks: Leaks in the exhaust system, near the sensors, can lead to incorrect temperature readings and trigger the 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 09, 2024
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Code P20E4 GMC Description

The P20E4 diagnostic trouble code (DTC) indicates a correlation issue between Exhaust Gas Temperature Sensor 2 and Exhaust Gas Temperature Sensor 3 on Bank 1 of the vehicle's engine. This code is specific to GMC vehicles and is related to the exhaust system's temperature monitoring functionality.

OBDII Code P20E4 GMC - Exhaust Gas Temperature Sensor 2/3 Correlation Bank 1
P20E4 GMC Code - Exhaust Gas Temperature Sensor 2/3 Correlation Bank 1

Common Causes of P20E4 GMC

  1. Faulty Sensors: The most common cause of this code is a malfunctioning Exhaust Gas Temperature Sensor 2 or Sensor 3.
  2. Wiring Issues: Corrosion, damage, or poor connections in the wiring harness connected to the sensors can also trigger this code.
  3. Exhaust System Leaks: Leaks in the exhaust system, near the sensors, can lead to incorrect temperature readings and trigger the code.
  4. ECM Malfunction: A malfunctioning Engine Control Module (ECM) may not be able to interpret the sensor data correctly, causing the correlation issue.
  5. Catalytic Converter Issues: Problems with the catalytic converter, such as clogging or damage, can affect the exhaust gas temperatures and trigger the code.

Symptoms of P20E4 GMC

  1. Check Engine Light: The most common symptom associated with this code is the illumination of the Check Engine Light on the vehicle's dashboard.
  2. Reduced Fuel Efficiency: A correlation issue between these sensors can lead to incorrect fuel adjustments, resulting in decreased fuel efficiency.
  3. Rough Idle: The engine may experience rough idling or fluctuations in RPM due to the incorrect sensor readings.
  4. Increased Emissions: A malfunctioning exhaust gas temperature sensor can lead to increased emissions, potentially causing the vehicle to fail emissions tests.
  5. Engine Misfires: Incorrect sensor readings can cause the engine to misfire, leading to a rough running engine and potential damage over time.

How to Fix P20E4 GMC

  1. Diagnostic Scan: Begin by performing a diagnostic scan to confirm the presence of the P20E4 code and identify the specific sensor causing the correlation issue.
  2. Sensor Replacement: Replace the faulty Exhaust Gas Temperature Sensor 2 or Sensor 3 on Bank 1, depending on which sensor is causing the correlation issue.
  3. Check Wiring: Inspect the wiring harness connected to the sensors for any damage, corrosion, or poor connections. Repair or replace any faulty wiring.
  4. Address Exhaust Leaks: Check for any leaks in the exhaust system near the sensors and repair them to ensure accurate temperature readings.
  5. ECM Reset: After completing the repairs, reset the Engine Control Module (ECM) to clear the code and recalibrate the system.

Cost to Fix P20E4 GMC

The typical repair costs for addressing a P20E4 code can vary depending on the specific cause of the issue and the vehicle's make and model. However, as a rough estimate, the cost of replacing a faulty Exhaust Gas Temperature Sensor can range from $100 to $300 per sensor, including parts and labor. Additional costs may apply if wiring repairs or other components need attention.

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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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