Hi!

What harm can cause if lambda sond is broken???
I think mine is,
because sometimes warning light turns on.
It may be off most of the time, but sometimes it turns on when driving or right after start up.

Your lamp is probably working as should. If it comes on right after ignition start it is simply doing a lamp test. However if it is coming on, no matter for how short of time during driving, then you have a fault that has been recorded and should be checked out by your dealer. The lambda sond or "check engine" lamp has everything to do with the emissions specs and the overall performace of your engine that inturn can affect emissions if not to spec as well.

ok...thanks tonyg.
Car is running very well, but i think i´ll have to take it to the service dealer then to check it out.
Last time when they changed my manifold, they said that there might be fault in my first lambda sensor...but after that it stayed off for like 2 months.