After giving someone a jump start, my 'Check engine" light has been on. What has caused this?

You will need to have your codes read. Many auto parts stores do this for free. There are at least 150 separate issues that could light your check engine light.

this is for every one out their to get the word out.DO NOT HOOK JUMPER CABLES TO A COMPUTER CAR WILL of 9 OUT OF 10 TIMES DAMAGE YOUR CAR EVER SO SLIGHTLGY.

Try unhooking the battery for a few minutes to reset the computer.If this does not work then the computer may be damged.Get a diagnostics done. Advanced Auto Parts will usually run a diagnostics for free.

i have a 2007 ford focus 1.6i duratec engine, i jumped started my car and two days later the car went completely dead, no light on the dash no crank, then i got an auto electrician to come out and he managed to get the lights back onto the dash but no crank, after testing evrything on the car from ecu, fuses, relays even programming and coding the car will still not start up, the diagnostic tool cannot fine the ecu, engine system fault. wat can cause this

Well I help a person than my car didn't work. So I check my battery and it was loose. But than I notice the engine lights stay on. I'm gonna try to take the battery off and out back in like the gentleman said above ☝️