Code P0420?

[scubadawg]

I changed to 200 cell cats, drove for 3 days, no codes until this morning.

At the same same of cats install, installed an IPD plenum, and an Evolution motorsport CAI with AEM dry filter.

Since I put this stuff in, when I first satrt up I get a high pitch sound like the air compressor that I had to move for the CAI, and oncassionaly when I drive it goes on for a few seconds. Could this code be the pump on the drivers side?

If there was some oil that got of the o2 Sensor would that cause the fault code also? any way of cleaning?

Car is a 2002 C2 coupe, with 6speed.

I got Code P0420

P0420 Catalyst System Efficiency Below Threshold (Bank 1) Heated Oxygen Sensor/Catalytic converter Failed emissions test -- If catalyst is collapsed or otherwise plugged, it will result in increased exhaust system backpressure, reducing engine performance, increasing emissions Catalyst contamination or damage, Heated Oxygen Sensor or circuits, Powertrain Control Module and programming (Bank 1)

Edited April 13, 2009 by scubadawg

[SH-GT3]

Taking a stab at this - sounds like the 200 cell cats aren't doing enough to satisfy the post-cat 02 sensor.