Quick question - Engine Check Light

[stew123]

I've got my car booked in to have the knock sensor replaced...engine check light on inside etc....quick question though:

 

With a standard ECU does the engine revert to "safe" mode when the light is on, and am I in danger of damaging anything if a run around like this ??

 

I know that in my old VTEC Honda when the light was on this is what happened, and I'm a bit concerned about hoofing it around and then finding out the engine was running lean or something.

 

Apologies if this is covered in other threads - I've looked at a load on the Search facility but not found one that covers this so far.