Toyota FORTUNER 2021 Owner's Manual page 383

Checking battery fluid
Check that the fluid level is between the upper line and lower line.
Upper line
1
Lower line
2
If the fluid level is at or below the
lower line, add distilled water.
Adding distilled water
Remove the vent plug.
1
Add distilled water.
2
If the upper line cannot be seen,
check the fluid level by looking
directly at the cell.
Put the vent plug back on and close it securely.
3
6-3. Do-it-yourself maintenance
Low
381
O.K.
6