I got a omission light on my 206 and it won't start I've checked all the fuses and sensor plugs and it still won't start can you help

i got a ommision light on my 206 and it wont start ive checked all the fuses and sensor plugs and it still wont start can u help

Does the engine turn over but not start?
Have any of the engine systems (battery, spark or fuel injector pulse?) been tested yet?