2005 997 Ck engine light in red

[rhart]

Go to workshop.

I'm thinking of buying this car but want some opinions from the mechanics here:
Here is the history. Car was parked last two years and only used rarely. Hooked to trickle charger. After sitting the last time for a couple of months owner get in to start it and the red go to workshop warning lit up. When parked it was not on. He got in and took it for a drive and it seemed to operate normally at all speeds.
40,000 miles
6 speed
Question: Can this be something minor? Car is running fine.
Thanks in advance for your help.
Can't do a PPI in this case....