Code P2423 indicates that the engine computer has detected the hydrocarbon (HC) adsorption catalyst on Bank 1 is not storing and oxidizing hydrocarbons efficiently. This typically means the specialized catalytic converter is degraded or failing to meet required emissions standards.
The catalyst substrate has deteriorated, melted, or become contaminated, reducing its ability to trap and burn hydrocarbons.
An exhaust leak upstream of or near the catalyst allows excess oxygen to enter, skewing sensor data and affecting catalyst efficiency calculations.
A degraded or failed upstream or downstream oxygen sensor is providing inaccurate exhaust gas readings to the engine computer.
An engine condition that introduces excessive unburned fuel can overwhelm the catalyst, causing it to fail efficiency tests.
The engine computer has an internal failure or software calibration issue causing an incorrect efficiency calculation (extremely rare).
Yes, you can generally drive with this code as it rarely affects engine performance or drivability. However, the vehicle will fail an emissions test and emit higher pollutants.
Often it does, because the HC adsorption catalyst degrades over time. However, exhaust leaks or faulty oxygen sensors must be ruled out first, as they can mimic a failed catalyst.
No. Replacing the engine computer is almost never the correct fix for this code. The PCM is simply reporting that the catalyst efficiency is low; the actual fault is almost always a degraded catalyst, an exhaust leak, or a faulty sensor.
It is a specialized catalytic converter designed to trap unburned hydrocarbons during cold engine starts, and then burn them off once the exhaust system reaches normal operating temperature.