Remember, there is an auto-off feature on the JIC. If you do not try to start your car within 30 seconds of powering ON the JIC, it will automatically shut itself off.
A poor connection between the clamps and the terminals can prevent a successful engine start. Disconnect the JIC from the clamps, and then adjust the clamps to ensure the most secure connection on both sides of the clamps. Reconnect the JIC and try again.
If vehicle is not in park/neutral, this could be preventing you from starting the engine.
Check whether the charge level of the JIC is too low.
Dirt on the accumulator terminals may hinder conductivity. Clean them with a wire brush or a dry towel.
Check if your engine’s characteristics match the ones your JIC is suitable for.
There may be other functions in your vehicle that aren’t working properly. Contact your car service center.
If JIC will not power on after a jump start, connect to a charger to “reset. Use the outlet if at home, or the cigarette charger if on the road.
Check that the charger is securely attached to the JIC input. Make sure you are using the input port and not any of the output ports.