Best guess is an ignition problem.... information on the car is a tad skimpy
for any "close" guessing. Since the CEL has been coming on, the "mechanic"
will scan for codes.... This works well as long as nobody has been
disconnecting and reconnecting things to see what happens and it also works
well if someone hasn't been disconnecting the battery to turn off the light.

The PCM collects information that can be valuable in diagnosing the concern.
'Erasing" the information inadvertently or adding spurious information can
make the diagnostic road long and hard....