Catalytic converter sensors

Types of catalytic converter sensors

A catalytic converter is a device fitted to the exhaust system of a vehicle that helps to reduce the emission of harmful gases into the environment. The toxic gases that the converter helps to reduce are primarily carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). It achieves this by converting these gases into less harmful emissions like carbon dioxide (CO2) and nitrogen (N2). There are two main types of catalytic converters. The first is the two-way converter, which is mostly used in petrol engines. It converts carbon monoxide and hydrocarbons into less harmful emissions like carbon dioxide and water. The second is the three-way converter, which is used in diesel engines. This type of converter also does the work of the two-way converter but adds the oxidation of nitrogen to form nitrogen dioxide (NO2) which is used to further reduce emissions in the engine upstream of the converter.

• Oxygen sensors: These are situated immediately before and after the converter in the exhaust system of the vehicle. The oxygen sensor before the catalytic converter monitors the level of oxygen in the exhaust gases leaving the engine while the one after the converter measures the oxygen levels in the exhaust gases that are leaving the converter. This second reading tells the engine control unit (ECU) how effective the catalytic converter is at removing oxygen from the exhaust. A healthy catalytic converter will result in a smaller difference in the readings of the two sensors. If the difference is significant, it could mean the converter is failing, and it is time to look for a replacement.
• Temperature sensors: Catalytic converters are very sensitive to temperature changes. They work optimally at a certain temperature range. If the temperature is too high or low, the efficiency of the converter is affected. The temperature sensors monitor the temperature of the exhaust gases entering and exiting the catalytic converter to ensure that the converter is operating within the ideal temperature range. It relays this information to the vehicle's engine control unit (ECU), which makes adjustments where necessary to keep the temperature stable. If the temperature is not within the ideal range, it can lead to increased emissions or damage to the converter.
• NOx sensors: These sensors are located in the exhaust system upstream and downstream of the catalytic converter. They measure the concentration of nitrogen oxides (NOx) in the exhaust gases. The NOx sensor before the converter measures the level of NOx emissions entering the converter, while the one after the converter checks how effective the converter is in reducing NOx emissions. The readings from these sensors help the vehicle's emissions control system optimize the performance of the catalytic converter and ensure compliance with emissions standards. If the NOx converter is not working well, the levels of NOx in the exhaust will increase, and the emissions control system will throw a warning.

Specification and Maintenance of Catalytic Converter Sensors

Each model of the catalytic converter comes with its own specifications. Here are some of them:

• Voltage:

  Catalytic converter sensors require power to function. The amount of power they use is called voltage.

• Current:

  Current is the amount of power flowing through the sensor at any given time.

• Resistance:

  Every catalytic converter sensor has a different amount of resistance to the flow of current. This is called ohms.

• Temperature:

  Some sensors monitor the temperature of exhaust gases. This is important because different gases require different levels of conversion.

• Signal Type:

  Catalytic converter sensors send signals to the engine control unit (ECU). This signal is used to let the ECU know what is happening inside the converter. The signal type is usually voltage, frequency, or current.

Just like any other part of a vehicle, maintaining the catalytic converter is important. Here are some of the maintenance tips:

• 1. Ensure that all exhaust leaks are fixed. Even a small leak can cause problems for the sensors.
• 2. Use high-quality motor oil and change it on time to keep the engine running well.
• 3. Keep the air filter clean and replace it when needed to ensure good airflow to the engine.
• 4. Only use fuel that meets the manufacturer's requirements. Avoid fuels with additives that could harm the sensors.
• 5. Address any engine issues immediately. Warning lights or codes can indicate problems that need attention.
• 6. Ensure proper maintenance of the engine. This includes regular tune-ups, maintaining proper tire pressure, and addressing any engine-related issues. A well-maintained engine reduces the workload on the catalytic converter and can prolong its life.
• 7. Avoid short trips where the engine doesn't reach optimal operating temperature, as this can lead to incomplete fuel combustion and increased emissions.
• 8. Avoid overloading the vehicle, as this can strain the engine and, consequently, the catalytic converter.
• 9. Be cautious with certain fuel additives or cleaners that claim to improve performance. Some of these products can be harmful to the catalytic converter.

How to choose catalytic converter sensors

Choosing the right catalytic converter is no easy task, especially when faced with various options. It requires careful consideration of several factors. Here are some of the most important:

• Vehicle compatibility

  Firstly, buyers should consider whether the vehicle is gas- or diesel-powered. Gas-powered vehicles usually have more space for the catalytic converter. The make, model, and year of the vehicle should also be considered. This is because the vehicle's design will affect the size and type of converter that is needed. Buyers may also want to consider the emissions regulations in their area. Some places have stricter emissions standards than others.

• Quality and certification

  Buyers should ensure that the catalytic converter they choose is certified. This is because the certification shows that it has been tested to meet emissions standards. It is also a good idea to look for converters that have the EPA or CARB (California Air Resources Board) certification. These agencies are responsible for setting emissions standards in the United States and Canada, respectively. They test and certify products to ensure they meet the required standards.

• Flow rate

  Flow rate is another important factor to consider when choosing a catalytic converter sensor. This is because the flow rate affects how well the converter works. A higher flow rate means that more exhaust gas can pass through the converter, which reduces back pressure and improves performance. However, it also means that the converter will wear out faster because it is working harder. Conversely, a lower flow rate means that the converter will last longer, but it could cause problems with engine performance.

• Warranty and brand reputation

  Buyers should choose a catalytic converter from a reputable brand, as this is a good way to ensure quality. They should also look for converters that come with a warranty. This shows that the manufacturer stands behind its product and is confident in its durability and reliability.

How to DIY and replace catalytic converter sensors

It is advisable for car owners to seek professional help when their catalytic sensor needs replacement. However, it is possible to replace the sensor as a DIY project. Here is how to replace the catalytic converter sensor.

Get the right tools for the job. A 10 mm socket wrench, oxygen sensor socket, ratchet extension, jack, and jack stands are needed. Get the right catalytic converter sensor replacement for the vehicle make and model. Turn off the ignition and ensure the vehicle is parked on a flat surface. Engage the parking brake and put on wheel chocks. Raise the vehicle with a jack and jack stand. Locate the old sensor and use the wrench to remove it. The sensor is usually located under the vehicle close to the catalytic converter.

Use the socket and ratchet to unscrew the sensor from the vehicle. Screw the new sensor into the vehicle using the oxygen sensor socket and 10 mm wrench. Tighten it carefully to avoid stripping the threads. Don’t use excessive force when tightening the sensor. Recheck the sensor's alignment and position and ensure it is properly installed. Once done, lower the vehicle and remove the jack stands. Start the vehicle and check for any error codes on the dashboard.

Ensure there are no check engine codes or error messages after installing the new sensor. The process of installing a sensor is almost similar, regardless of the type of sensor being replaced.

Q and A

Q1: How many sensors are in a catalytic converter?

A1: Most cars have two O2 sensors. One is before the catalytic converter, and the other is after the cat.

Q2: What do catalytic converter sensors detect?

A2: They check the exhaust for unburned fuel. They help the car control the air-fuel mix, while the other one checks if the converter is working.

Q3: What happens if a catalytic converter sensor fails?

A3: If it fails, the car won't run right. It could make the engine run rich or lean. That means too much fuel or not enough. Either way, the engine light will come on, and the car could use more gas and hurt performance.

Q4: Can the car run with a faulty O2 sensor?

A4: The vehicle can still run, but it may not perform well. The engine could be using more gas, and emissions would be higher. So it is better to get it fixed.

Q5: How long does it take to replace an O2 sensor?

A5: Replacing an O2 sensor is pretty quick. It usually takes 30 minutes to an hour max, depending on the location.