nissan workshop usually jz tested your vehicle using those
specialised tester that look like multimeter..
if the tester dont show any problem, they will jz treat it as no
prob.
my bf was having serious problem with his new car when he jz bought
it within 7 days. there was a few times within a mth or so, when he
start the car, the warning light will on. so he called them, bring
the car down to check for a few times. they checked and say no
prob. till once, the car cant start at all. then they check in
details and find out that the cable has prob and the one of the
part need to be change totally.
try and complain & ask them to check carefully. tell them that
this isnt the 1st time that the problem occured. unless the car is
so unreliable that the problem is so normal.