Lexus IS F 2012 Owner's Manual page 406

4-3. Do-it-yourself maintenance
Battery
Check the battery as follows.
■ Battery exterior
Make sure that the battery terminals are not corroded and that there
are no loose connections, cracks, or loose clamps.
■ Checking battery fluid
406
Terminals
Hold-down clamp
Ground cable
Check that the level is between
"UPPER LEVEL" and "LOWER
LEVEL".
"UPPER LEVEL"
"LOWER LEVEL"
If the fluid level is at or below
"LOWER LEVEL", add distilled
water.