P0402 Code Error And Engine Management Light On

[avanbueren]

I have fordgalaxy mk2 2.3 petrol auto and engine management light came on with fault code P0402 Catalyst system efficiency below threshold bank 1

 

Not sure if it I cat underneath car as was told it could be by garage but could it be EGR valve?   what tests can I do to make sure its cat and nothing else

[BrianH]

theres some questions been asked that you didn't answer in your other thread about this > http://www.fordgalaxy.org.uk/ford/index.php?/topic/26873-p0420-catalyst-system-efficiency-below-threshold-bank-1/?hl=catalyst

 

It might be worth taking the cat off and having a look inside it - theres a reasonable chance if its knackered if the honeycomb isn't intact (this can be down to underlying issues like misfires!).

 

Its also possible the secondary sensor is actually the problem - we don't know whats coming out of the exhaust, if the emissions appear right on a tester that suggests the sensor AFTER the cat is not working for some reason (broken wires/connectors a possibility as well as faulty sensor).