Arduino, solenoid driver and current limiter

You only have about 5.8uF downstream of the current limiter so all of that good stuff in the datasheet is useless. You are charging an inductor, not a capacitor.

It also seems like this chip is upstream of a reverse-polarity-protection diode. It is not rated for negative voltage so there is no protection.

What is supplying this 12V that needs such a large capacitor (2200uF) on the input?