high emmision light

[LUIGI-3]

hi, i bought my passat last tuesday, test driven it prior agreeing buy. then on day of purchase i drove home, filled it with petrol and bang next morning i got is the high emission light staying on. Took it to local garage, had codes pulled and 2 codes came up- secondary air pump and lambda, they cleared codes and told me to see how it goes and come back if the light appear again, less then 24 hours light is back on again. so now im worried to drive it to avoid more damage, the car drives fine, pulls well, no smell of ,,rotten eggs" from exhaust. Only thing i noticed is decreased fuel efficency, i was getting 32mpg before light came on and now is 25 max is there something i can do before taking it to garage again for further investigation? cheers Mario