I have a dash error light (!)

Some cars have tire pressure sensors that can cause an indicator with an exclamation point to appear on the instrument panel.

Check the pressure in all of your tires.

Your car manual (probably crammed into your glove box somewhere) will have a diagram of all the instrument panel lights and a brief description of what they all mean.

Google the kind of car and it's year. Add the word ...dash symbols.

Look in your owners manual

Can also find those symbols on the internet

brake system warning

If it looks like a deflating tire with an exclamation mark inside, its the check your tire pressure light.

If its a triangle with exclamation mark inside its the check engine light.

It means you have one or more tires with low air pressure. Check the tires for pressure and for nails or any visible damage.

it is the tire pressure monitor. It means one of your tires has low air pressure.

it mean that your tire pressure is low or tire pressure sensor is malfunctioning ,set tire pressure at 35 psi and drive for 1/4 mile to see if the ligth goes off

Normally,,,the exclamation mark in car dash board defines the "Handbrake"...if you pull the hand brake lever up it lights on...sometimes there can be problems with that switch(all time it can be in on)...
(PLEASE VOTE AS "Fixya" for my help)..................................