Saab 9-3 P0420: Catalyst System Efficiency → Below Threshold → Bank 1
This page is meant to help you troubleshoot the Saab 9-3 P0420 trouble code. It covers P0420 meaning, symptoms, causes, and possible solutions. WIth the 9-3, OBDII P0420 is often caused by a bad oxygen sensor, but there can be other causes as well. Jumping straight to replacing the O2 sensor can cost … Read more