Leave car electrician has failed to start (4)
I believe the answer is:
park
'leave car' is the definition.
(I've seen this before)
'electrician has failed to start' is the wordplay.
'electrician' becomes 'spark' (informal term for an electrician).
'has failed to start' means to remove the first letter.
'spark' with its initial letter taken off is 'PARK'.
(Other definitions for park that I've seen before include "Scottish explorer" , "Public gardens" , "Large public garden" , "Estate < car storage space" , "Leave car - recreational area" .)