Only TCS light is on. As shown. What might be the issue and will a basicish scanner sniff out a bad sensor?

 

Year, trim, transmission, history? I'm betting '12-'13 Sport automatic.

 

Oh boy, I can't remember the year. Probably 2012. Automatic base model.
50k miles, spends most of its time just sitting in very hot/humid east Texas. Battery has died a few times from lack of use, the infamous "won't go out of park" issue has been going on for a while too.

 

Some of the bluetooth scan tools + phone app are pretty comprehensive. I bought an Ancel V5BT, but that's probably more than you want to spend.

Transmission range switch?
The ECM controls the shift lock solenoid (part of the shifter). It needs to see the transmission in park, the brake pedal pressed, and the accelerator not pressed to activate the solenoid which lets you out of park. If there's a problem with the range switch, the ECM can't tell you're in park and won't activate the solenoid. A brake pedal switch problem (such as the plastic stopper on the pedal arm crumbled) would probably make the brake lights stay on all the time, or no brake lights at all. The accelerator pedal has redundancies and its own error codes.

First step on the TCS issue is to check the error codes. Most auto parts stores have a scan tool they will plug in to retrieve codes for free. The shifter should have a lock override under a little cover if that's all that's keeping you from driving it. Check the manual, but procedure is typically to press and hold brakes, use your key to press and hold the override, shift to neutral, release the override, start the car. You should be able to shift freely until you shift back to park.