System Too Lean ? ??

i got one of those ODB2 check engine scanners because my CE light came on. the error i got was 0171 which means "SYSTEM TOO LEAN (Bank 1)". thats all the description the manual gave me.

does anyone know what this means? my dad is guessing that it is not a problem as long as the motor is running efficiently. he said to woory only if it read "too rich".

is it harmful to just leave it alone.

It could be harmful to leave it alone. If you have run the truck out of gas that could be the reason for the light. If you ran it out of fuel and canceled the light it shouldn't come back unless you have some other problem. To learn more and some suggested causes see this article.
http://www.4x4wire.com/toyota/4Runner/tech/OBDII_ECU/

Clifton

It could be harmful to leave it alone. If you have run the truck out of gas that could be the reason for the light. If you ran it out of fuel and canceled the light it shouldn't come back unless you have some other problem. To learn more and some suggested causes see this article.
http://www.4x4wire.com/toyota/4Runner/tech/OBDII_ECU/

Clifton

it hasnt run out of gas and i have reset the light and it came back on the following day.

i'll check out the link you posted and THANKS!

there is a chance it could be your mass air sensing element might be just dirty. i would try cleaaning it with some elec spray cleaning. just remove your mass air from the airbox and spray the element down and let it dry and see what happenes there thats prob the cheapest fix. it could also be your forward O2 sensor. hope this helps