If your vehicle has power locks, it has a programmable automatic door unlock feature.
The doors can be programmed through the Driver Information Center (DIC) to automatically unlock several ways. See DIC Vehicle Personalization for more information.
Chevrolet Cobalt Service & Repair Manual. Engine Oil Light, Diagnosis & Testing
1.
Understand and validate customer concern.
Inspect visible system components for obvious damage or conditions
that may cause concern.
2.
Inspect for related bulletins, recall/field
actions and preliminary information.
...