It's not 400uF but 400pF.

For more information see this link (among many others !) to a document on the Philips website

www.semiconductors.philips.com/ acrobat/literature/9398/39340011.pdf

Every I2C device has its own in/out capicitance. Look this value up in the datasheet and add them up together
Also beware of pcb traces.

Peter