P0420 Fault code immediately after fitting Prodrive full exhaust
 

Hi All

Just fitted a turbo back Prodrive exhaust to my 03 WRX blob and have immediately got the following fault code appear:

P0420 Catalyst System Efficiency Below Threshold.

Is this normal when upgrading exhausts? I assume this is being triggered by being 1 cat lighter?

I did have to cut my 02 sensor wires as I couldn't get the sensor out whilst fitted to the car. I did however make sure all wires were reconnected correctly (including two black). Could it be that I may have a dodgy connection here?

Many thanks!

Needs the code turning off on the ecu rom, any mapper can do this.

have you tried resetting the code to see if it stays out? If teh code won't stay out then either replace the sensor with an uncut one or as above get the code turend off in the map (should be a quick fix)

Being a turbo back I assume its a sportcat you've fitted? If so then it needs mapped for it ideally and person mapping will sort your cel light also

Is there a brick in the catalyst can section? Someone hasn't made a de-cat by bashing the cat brick out?