2002 S80 T6 looking for suggestions on trouble code

Cale · Post by **Cale** » 25 Apr 2007, 23:02

I will try to keep it simple. I have a 2002 S80 T6 2.9 Twin turbo w/56,000 miles. Check engine light is on. OBDII reader shows two codes that I have cleared about 6 times and keeps coming back. The codes are PO432 (Main Catalyst Efficiency Below Threshold - Bank 2) and code PO422 (Main Catalyst Efficiency Below Threshold - Bank 1). What does the code "Main Catalyst Efficiency Below Threshold" realy mean? In most cases I do know it boils down to a bad O2 sensor in need of replacement. In my case the O2 sensors are fine. So does anyone know what would cause this reading knowing the O2 sensors are not bad? Any help on this would be great.

Post by **MadeInJapan** » 27 Apr 2007, 12:03

I posted in your other thread, but for the 02's to check out, I would suspect vacuum leak(s).