Pull the radio and make sure all the connectors are still connected to the radio, second try to determine which leads are power and ground and measure voltage on the leads coming to the radio, if you have voltage and it still will not power up after reconnecting, then consider replacing the unit if no voltage exist follow that backward toward the power source. Make sure key is in the correct position to have power available at the radio.
Check fuses. Check wiring connections
Have you checked fuses?
faulty brake light switch (on pedal)
Have the code read, repair the cause, and clear the code with a scan tool.
Possibly bad brake light switch, or broken/disconnected wiring.
Does it have trailer light wiring also? check that too.
First check your fuses. A common fuse that shares this circuit is the courtesy/dome light.
check the fuses
There are pages and pages of causes for a check engine light. You need to have it checked for codes with a scanner to know what to diagnose. After the repair you can clear the code with a scanner.
Defective or misaligned stop light switch check the bulb, brake filament might be burnt out
fuse or switch is bad get test light and check both side of fuse some fuses will not light up unless key is on
Answer50 miles are left when the fuel light comes on in a Dodge Stratus.