Powertrain Control Module Fault. It can also be a problem with the cooling system. I recommend you seek professional help at a GM dealership as there are TSBs on this code on your Cobalt.
P1682 A/T FI Signal A High Input (Acura, Honda)P1682 Charging System Voltage Too Low (Chrysler, Jeep)
Trouble code P1682 means: Charging system voltage too low
Trouble code P1682 means: Ignition 1 Switch Circuit 2
Charging system voltage too low.
P1682 Charging System Voltage Too Low
You have to find the cause of the charging system malfunction. It could be the alternator, wiring, or PCM.
Alternator going bad..replace it. Just had the same thing on my 2000 neon
It means the charging system voltage (is) too low, Check the alternator and the voltage regulator. The voltage regulator is a part of the powertrain control module or PCM.
908850
in the trunk under the carpet on the left side
the correct code is mhdjhflame
code pes 2009