The vehicle has a battery saver feature designed to protect the vehicle's battery.
When any interior lamp is left on and the ignition is turned off, the battery rundown protection system automatically turns the lamp off after 20 minutes.
This prevents draining of the battery.
Chevrolet Cobalt Service & Repair Manual. Passkey Module
On models equipped with the Passkey
Theft Deterrent System, a new password must be learned by the PCM when the
BCM/PCM has been replaced. When the PCM is replaced, the EEPROM calibration
is flashed into the new PCM. Refer to latest GM Techline or equivalent information
for PCM ...