P0440 Catalyst Temperature Sensor High Input (Bank 2): A Comprehensive Guide

Introduction to P0440 Error Code

Getting an error code P0440 in your vehicle can be a bit perplexing, especially if you aren’t an auto mechanic. So, what does this mean? The P0440 is a general OBD-II trouble code indicating an issue with the Evaporative Emission Control (EVAP) System, more specifically the catalyst temperature sensor.

What is a Catalyst Temperature Sensor?

The catalyst temperature sensor is a crucial component of your car’s exhaust system. It monitors the temperature of the catalyst (catalytic converter) to ensure it is working efficiently. If the temperature gets too high or too low, it can indicate a problem.

Function of Catalyst Temperature Sensor

The primary function of the catalyst temperature sensor is to ensure that the catalytic converter, a vital part of your car’s emission system, is operating at an optimal temperature. An excessively high temperature indicates an issue, thus triggering the P0440 error code.

Causes of High Input in Catalyst Temperature Sensor (Bank 2)

There can be several reasons for a high input error in the catalyst temperature sensor.

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Faulty Oxygen Sensors

The oxygen sensors are like the eyes and ears of the engine control unit (ECU). If they are not functioning correctly, they may give false readings, leading to a high input error.

Damage in Wiring and Connectors

The P0440 code may also arise due to damage in the wiring and connectors that link the sensor to the ECU. A break or short in these wires can cause the sensor to malfunction.

Clogged Catalyst Converter

A clogged or inefficient catalyst converter could also cause the catalyst temperature sensor to record high input.

Symptoms of P0440 Error Code

You might be wondering, how do I know if I have a P0440 error? Here are the common symptoms:

Check Engine Light

The most apparent sign is the illumination of the check engine light on your dashboard.

Poor Fuel Efficiency

If your vehicle is burning more fuel than usual, it might be due to a malfunctioning catalyst temperature sensor.

Reduced Engine Performance

Another symptom of a P0440 error code is a noticeable decrease in your car’s performance or power.

How to Diagnose and Fix P0440 Error Code

Diagnosing and fixing a P0440 error code may seem like a daunting task, but with the right tools and knowledge, it’s achievable.

Using an OBD-II Scanner

You can diagnose this error code using an On-Board Diagnostic-II (OBD-II) scanner. The scanner will retrieve the code and provide you with a starting point for your diagnosis.

Inspection of Oxygen Sensors

Inspect the oxygen sensors for signs of damage or contamination. If found faulty, they will need replacement.

Checking Wiring and Connectors

Inspect the wiring and connectors for damage or corrosion. Any damaged wires or connectors should be replaced.

Checking the Catalyst Converter

The catalyst converter should be checked for blockages or damage. If found to be clogged or damaged, it may require cleaning or replacement.

Prevention of P0440 Error Code

Prevention is always better than cure, right? Here’s how you can prevent the P0440 error code:

Regular Vehicle Maintenance

Regular servicing of your vehicle is a surefire way to prevent any sensor malfunctions. This should include checking the condition of the exhaust system and the catalytic converter.

Timely Replacement of Oxygen Sensors

Replace oxygen sensors as per the manufacturer’s recommendations. Generally, they should be replaced every 60,000 to 100,000 miles.

Proper Inspection of Wiring and Connectors

Regularly inspecting the wiring and connectors for any signs of damage or corrosion can prevent a myriad of sensor-related issues.


Dealing with a P0440 error code can be tricky, but with this guide, you should have a better understanding of what causes this issue and how to fix it. Remember, regular maintenance of your vehicle is the key to preventing such issues.


  1. Q: How serious is a P0440 error code? A: While a P0440 error code may not cause immediate damage to your vehicle, ignoring it could lead to serious problems down the line, including reduced engine performance and poor fuel efficiency.
  2. Q: Can I drive my car with a P0440 error code? A: While it’s not generally dangerous to drive with a P0440 code, it’s advisable to fix the issue as soon as possible to prevent further damage.
  3. Q: How much does it cost to fix a P0440 error code? A: The cost to fix a P0440 code can vary widely depending on the exact cause. It can range from $100 for replacing a sensor to $1000 or more for replacing a catalytic converter.