Potential lambda issue/engine light

[Singhpin]

Hello to members out there. 

First time poster so any help is appreciated. 

Recently on a drive when lulling away from some lights, it sounded like something had fallen from the front end of my car. Almost like a brief rattle. Very soon after an Amber engine light has appeared on my dash.

A diagnostic has been done and they've advised the error code is showing in the lambda sensor (post cat). 

 

Considering the noise heard sound like it was front end, is this the likely issue? It doesn't make sense to me but then I'm a bit noob.

Its given me no problems in terms of the drive, only issue I've noticed is a lower mpg. 

 

Any any all help is appreciated.

 

Thanks in advance! 

 

[Singhpin]

Anything? Thanks 

[iantt]

if thetes a rattle it could be the cat has broken up causing the mil light to come on. 

do you know what the error code is. 

can you get under car and thump the cat (when its cold) to see if theres a rattle?