Central Gas Furnace Quickly shuts down

It is getting colder now and some folks are turning on their heaters only to get no heat. The problem is the flame sensor most of the time:

They get contaminated and will not sense ignition. If the brain does not get a signal of ignition it will think raw gas is coming out and it will check 3 or 4 more times. Within 20 seconds it will shut down the gas valve. Replace this sensor or clean it real good with emory cloth or a brillo pad. Also take a look at all connections from the burner to the control. A loose or corroded wire will not get a signal back to headquarters that ignition has occurred and the dang thang will shut down.The control might be bad but make damn sure it ain’t something simple before you go blowing money on non refundable parts.LOL!