P0431 - WARM UP CATALYST EFFICIENCY BELOW THRESHOLD (BANK 2)

Diagnostic code P0431 OBD2 means that the Powertrain Control Module (PCM) has detected that there is a problem in the efficiency of the Catalytic Converter (TWC) heating function, in bank number 2. Bank number 2 corresponds to the side of the engine where cylinder number 1 is not. The Three Way Catalyst (TWC) has the function of reducing exhaust emissions. It consists of a filtration element made of ceramic and other metals, which are enclosed in a steel casing, located near the exhaust pipe. In order for the unburned harmful nitrogen oxides to be converted into harmless nitrogen ions within the catalyst, a filtration network and an extreme heat level of the engine exhaust is used. That’s why catalyst temperatures should reach 800°F.

The Catalytic Converter has two Oxygen Sensors, which are connected to the Powertrain Control Module (PCM) through the controller area network and send data to the PCM about the percentage of oxygen in the engine exhaust compared to oxygen in the ambient air.

• The Check Engine light is switched on at the dashboard.

If P0431 code has been set it may mean that one or more of the following problems have occurred:

• There may be a leak.
• It is possible that an Oxygen Sensor (O2) Sensor is not functioning properly.
• Perhaps the Catalytic Converter (TWC) is faulty, so its function is incorrect.

The steps to solve DTC code P0431 are as follows:

• First, you can check for exhaust leaks. Repair if you find one.
• Inspect all wiring and their respective connectors related to the Three Way Catalyst (TWC), if you find one of these components has corrosion or wear. You can repair or replace it if necessary.
• You can check the voltage of both Oxygen Sensors against factory specifications. Change one of these if they are not within the expected parameters.