y m I getting a PO621 code on my 01 Pontiac Grand AM?

Question

The check engine light and now the service vehicle light r on and the only thing I did before the service vehicle light came on and also before I got the PO621 code was jumped it cuz my battery was dead from leaving the key on by mistake.

Answer 1

P0621 Low alternator output

This code was more than likley set because the key was in the on position, as the battery drained. and the engine was not running.Clear the code,