Engine lights come on with an arrow pointing down what does that mean

it means that you have to have the fault codes read to determine the exact area of the fault
do that first and save money by not replacing what is not faulty

if your car has a standard transmission then the icon of the engine that has arrow pointing down might be an indicator that you need to down shift , as

the other symbol ive seen only once before it was on a Bmw and was a symbol for the valet mode , it down tunes the engine and inhibits all the luxury features (like radio) for just the valet to park your car , its possible these two icons are related

If this is the arrow that appears in the figure of an engine block, it indicates a "reduced engine power" condition. This usually means there is a problem detected by the computer that causes it to limit engine RPM's to 2000. You need to have a mechanic scan for fault codes.

It means reduced engine power. Check for vaccum leaks and at the very least, clean your throttle body. Reduced engine power is like a safe mode, needs to be check out right away.

ENGINE LIGHT WITH ARROW POINTING DOWN WITH A SQUARE LOOKING SYMBOL IS LOW COOLANT WARNING LIGHT.

On a saturn with a manual transmission the down arrow means to downshift to a lower gear and the
arrow pointing up means to upshift to the next gear.

LOW COOLING WARNING LIGHT.CHECK YOUR ANTIFREEZE LEVEL IT IS LOW.WHICH WILL CAUSE OVERHEATING AND ENGINE DAMAGE.

ARROW POINTING DOWN THAT A LOW COOLANT WARNING LIGHT.THIS WARNING MEAN ADD COOLANT QUICK AS POSSIBLE OR THERE WILL SEVERE ENGINE DAMAGE.

The red warning light is a box with two waves in it, an arrow pointing down and a T on the top indicates your Engine Coolant is low.