The malfunction light and powertrain light (spanner) may illuminate due to many reasons and may include engine, exhaust system, transmission, drive shaft, suspension, wheels, glow plugs (if diesel) and catalytic converter. Vehicle is safe to drive though diagnostic equipment is required from a technician to correctly diagnose and fix the issue.
I queried this with my local Ford service department.
They said that it might also simply indicate that the vehicle is due for a service.
As it is approaching 1 year old, this may well be correct.
NOT the most helpful of warning indicators!
I have had this on my Fiesta, when you first turn on the ignition (not engine) it sounds a warning chime, also flashes up with oil change required on the info panel. It first came on when I had clocked up 12250 miles.
If it is just a oil change you can turn it off by turning on the ignition (not engine) and depressing the accelerator and brake at the same time, after twenty seconds release both and it should have gone off, If it is still on there is another problem which needs addressing.
I will bear this in mind if I get such a warning light.
The only warning light I ever got on the Fiesta was that occasionally the traction control warning would come on. Never established why, but I left it for 2 years wthout a service and never got a spanner.
For those who have keyless entry/ignition, first just press the start/stop button - don't touch the pedals. That will bring up the dashboard lights, then follow the "accelerator and brake pedal" process.