Hello, I hope I can offer you some assistance.
When the warning light came on did the engine lose power? Did any other electrical concerns show apart from the indicators?
Let me know and I'll reply as soon as I'm able to.
if the car didn't lose power then the PCL will have come on due to an electrical concern rather than an engine management concern, the indicator and interior light concern would confirm this.
To start with I would check the fuse box inside the car on the passenger side. Make sure you have your radio code, disconnect and inspect the electrical connectors to the fuse box, this fuse box is also a control module called a GEM, this controls many electrical systems on the car. Make sure there isn't any sign of corrosion on any of the terminal pins in either the connectors or the pins in the fuse box especially the connectors on top of the fuse box.
If there is any corrosion then the fuse box will need replacing, a new fuse box will need to be programmed to the car, as I mentioned earlier it's also a control module.
If there is signs of corrosion then the cause is water ingress so the source of this will need to be found and repaired.
Start with checking as above, let me know if I can assist further and I'll reply as soon as I can.