Just had a Miltek fitted which has a sports cat in the downpipe to my MY01 WRX with a de-catted up-pipe. However I am now getting a CEL (P0420 Catalyst efficiency below threshold) which suggests that either the CAT is not performing as it should, the lambda sensor is knackered or I need a CEL fix?

Ideas peeps?

you need a CEL fix..

loads of info on here about it, type it into search

Phil

or get it ecu tek'ed and get them to change the tollarances :D
hows it going, does it feel any better with the down pipe?

Im not sure but is this is the same code for a melted EGT sensor, may be time for 2.2k resistor fix?

you will be catching me up now ;)

[Edited by WRX_Rich - 12/22/2003 5:53:22 PM]

even with a sports cat??? Litcho's web site says -

"304 Austenitic Stainless Steel Construction
Full Mandrel bent Pipe work
Hi-Flow Sports CAT with extra heat shielding
Laser cut finish
Externally mounted brackets for better heat protection
No boost problems
No Check Engine Light (CEL) issues"

Clicky for page

Rich... EGT fix done already to avoid problems :D

Pulls far better from lower down and sounds really crisp!!! throttle response better too... pops and bangs like a good un on overrun!!!

[Edited by Fizz - 12/22/2003 5:54:47 PM]

so we gonna try and get a deal if we buy 2 turbos lol -

BTT for more information!!!

Fizz,

I had the same CEL on an MY02 after fitting a full APS system with no cats.
I was getting the occasional CEL, so ordered the CEL fix. Since I have received it (and not fitted it) the CEL is no longer appearing!
The temperatures have dropped quite a bit here (only 25C now ;)) so that may mak a difference.
If you can easily reset the CEL (and identify which one it is) - e.g. you have a SECS or similar, then I would suggest leaving it for a while to see if it settles down.
If the CEL continues then the CEL fix would be the way forward.

Daz, Thinking about it I had a CEl light come on last time I went out to TSL

didn't have my sheet to tell me what it was and I just reset the ECU. It went off, never seen it again I assumed this was the same code as what you have ( as limp mode didn't come in) and I have a sports cat in the downpipe aswell

And here Neil we have wright now -4C that isn't comparable with the English weather but is low enough for us.
By thw way it's more possible to have PO420 code with cold weather rather with hot!
Mery Christmas.
JIM