Limp mode can occur on any flavour of car. If the car detects a problem in that it can't talk to various bits of engine electrickery, it uses a programme for fuelling & ignition that it knows will do the job of moving the car ..... it knows that it could do better, but in the absence of all the info it would like, then limp will suffice.
You'll know when the car is in limp mode because you'll have your foot buried in the carpet & the car doesn't respond ..... the engine management might or might not be lit.
As above. The other time limp mode can occur is if it detects a condition the ECU thinks could cause serious damage - for example over rich mixtures, misfire etc. Limp mode will put the engine onto a very basic map to minimise damage but it will still allow the car to be 'driven' to a dealer albeit limping along slowly.