ive just fitted a turbo back 3" exhaust system to my 2004 wrx and put the lambda in as normal too see, and a week later the CEL still has not illuminated!?! dont get me wrong this is a good thing the CEL works as ive checked with a diag tool so thought this very strange no cat and no fault!?! anyone else had this???

 

One or two lambda's ?

 

only one it went direct into the cat on the standard system

 

anyone else come across this godsend!?!

 

if it has 1 lamda after the turbo but before cat you wont get a light on as its measuring the engine efficaincy, how well the the engine is burning the air and fuel the cat is after so all good just raised emmisions at the tailpipe if you have a second one under car but after the cat you will get a light on as this is measing the cat efficiantly steve

 

A mate had this untill he gunned the car and then the Cel came on. Car has since been remapped but it took about 3 weeks for the cel to come on.