Hi Guys,
I have got a problem with CEL P0420, P0430 CATALYST EFFICIENCY BELOW THRESHOLD....reset the ECU but light up again after 100km. FYI- (mods- Gruppe M air ram system, cargarphics headers, cats and mufflers)
HELP! Any idea what causes it and solutions?

 

Too much flow Are these 100 CEL cats? Might be the cause, 200 CEL's are less likely to throw a code.

 

100 cell cats are the issue.

 

They are 200 cell cats. Possible of a dead cats? I have only done 5000km on the car but 4 track days.

 

I was told not to change out the exhaust manifolds (headers), because it could possibly cause CEL problems. Same advice was given on ceramic coating the whole exhaust system, including the turbo's. Could lead to possible warranty claim issues.

 

May have to contact CG, but I think you're gonna end up taking off one thing at a time to find the culprit. Do the easy stuff first, intake, then headers, ....
GL

 

Or do what I did - get a Protomotive ECU. 200-cell cats, 100-cell cats, NO cats... no problem
Oh, and there's a bit of extra power too

 

You should be able to run O2 simulators to the post cat wiring harness