No.
No. The oil pressure sensor is not required for the engine to run.
The normal cause is a blown fuse.
Faulty sending unit.
You use a scan tool after repairing the cause of the code.
You can unhook the battery or use a scan tool to erase the code. If the cause is not repaired, the light will return.
The "bus" is the system that the computers on the car use to communicate with each other. "no bus" means that something has happened to cause a failure in the system.
Motor mounts.
The heater core has failed.
P1776, solenoid switch valve latched in low/reverse position. The usual cause is dirt in the transmission valve body.
Possible bad ECM.
While driving, hit something probably while going over a bump or hitting a rock. Object can be low enough to clear front clip and cause severe damage.
The Alero is made by Oldsmobile not Chrysler. My first suspicion would be a failed fuel pump or clogged fuel filter.