Transient Voltage Suppressor

I have circuit in which Transient voltage supressor is connected...part name 1N6277A..I don't know how to check this with multimeter...it shows 6 ohm across its terminal...what should be the value?? how to check it is correct or not?
http://www.datasheetcatalog.org/datasheet/vishay/15ke.pdf

Its a very good bet that the transient absorber has absorbed its last transient; it is shorted.

It should look like an 18.9 volt Zener diode. It would measure one silicon diode drop (about 0.6 volts) in one direction and it should appear very much like an open circuit in the other, unless your ohmmeter puts out 18 volts or more.