economy mode active engine cranks but wont start

Looks like your battery is too low. Try charging it up or with another battery/cables.

EDIT :

Economy mode is activated when the car detects an energy drain. Either you left the CDplayer on for more than 30 minutes without the engine turning or you left your car door open for more than 45 minutes OR battery voltage is too low.

Well, to deactivate the economy mode, in theory, you're supposed to turn on the engine, shut it down and turn it on again.

Since the engine is not turning, I'm guessing it is a battery issue. Anyway, for any battery issue, the first thing should always be to charge your battery to eliminate the most common problem. :)