DTC P0420? malfunction in cat?
#1
Teching In
Thread Starter
Join Date: Feb 2003
Location: lindenhurst,NY
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
every now and then my SES light will come on for a few days then shut off for a for a month or so then come back again, i hooked up and obd 2 scan tool to my car and scan for codes it had a record of a code P0420 which it said was a "low catalyst efficiency bank 1", does this mean one of my cats is bad or that my o2 sensors are malfunctioning? or is it something else? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> the only mods i have to my car are a lid and corsa catback, but i couldnt see either of these causing a trouble code for the catalytic converters. any info would be greatly appreciated, thanks
#2
Teching In
Thread Starter
Join Date: Feb 2003
Location: lindenhurst,NY
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
thanks for the advice jay, ill try that the next time its nice outside, the weather really sucks around here right now, either way i still have a warranty on the o2 sensors and cats so if they're bad ill just get a new one from the dealer <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
#3
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
I'd swap the two rear O2 sensors around. If it comes back as a P0410, then you know it is a bad O2 sensor. If it stays the P0420, then it may be a bad cat.