Engine-CodesGeneric – P2478

P2478 Code - Exhaust Gas Temperature Out of Range Bank 1 Sensor 1

Quick Answer

The P2478 code indicates that the exhaust gas temperature in Bank 1 Sensor 1 is out of the expected range. Common causes include Faulty exhaust gas temperature sensor, Wiring or connector issues, Exhaust system leaks. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means
P2478 indicates Exhaust Gas Temperature Out of Range Bank 1 Sensor 1.
Common causes
Common causes include Faulty exhaust gas temperature sensor, Wiring or connector issues, Exhaust system leaks.
Severity
Moderate - service should be scheduled soon.
Can I drive?
The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
Table of contents Created and updated by William Orellana on Aug 25, 2024
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Code P2478 Description

The P2478 code indicates that the exhaust gas temperature in Bank 1 Sensor 1 is out of the expected range. This sensor is responsible for monitoring the temperature of the exhaust gases before they enter the catalytic converter. When the exhaust gas temperature is out of range, it can lead to inefficient combustion, reduced engine performance, and increased emissions. This can potentially cause damage to the catalytic converter and other engine components if not addressed promptly.

OBDII Code P2478 - Exhaust Gas Temperature Out of Range Bank 1 Sensor 1
P2478 Code - Exhaust Gas Temperature Out of Range Bank 1 Sensor 1

Common Causes of P2478

  1. Faulty exhaust gas temperature sensor
  2. Wiring or connector issues
  3. Exhaust system leaks
  4. Mixture of incorrect fuel or air ratio
  5. Exhaust system restrictions or blockages

Symptoms of P2478

  1. Decreased fuel efficiency
  2. Engine misfires
  3. Rough idling
  4. Check Engine Light illuminated
  5. Poor acceleration

How to Fix P2478

  1. Diagnose the issue using a diagnostic scanner to confirm the P2478 code and pinpoint the exact problem.
  2. Inspect the exhaust gas temperature sensor and its wiring for any damage or corrosion. Replace if necessary.
  3. Check for exhaust leaks and repair or replace any damaged components.
  4. Ensure proper fuel and air mixture by checking the fuel injectors, oxygen sensors, and air intake system.
  5. Clear the error code, reset the system, and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P2478

The cost of repairing the P2478 code can vary depending on the specific cause of the issue. On average, the repair cost can range from $100 to $400, including parts and labor. Keep in mind that diagnostic time and labor rates can vary, so it's recommended to get quotes from different auto repair shops to determine the most cost-effective option.

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Code P2478 Information for Specific Makes

  • P2478 Chevrolet — Exhaust Gas Temperature Out of Range Bank 1 Sensor 1
  • P2478 Dodge — Exhaust Gas Temperature Out of Range Bank 1 Sensor 1
  • P2478 Ford — Exhaust Gas Temperature Out of Range Bank 1 Sensor 1
  • P2478 GMC — Exhaust Gas Temperature Out of Range Bank 1 Sensor 1
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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