Though the Guru Granth Sahib and the Dasam Granth refer to the words Shiva, Vishnu, Krishna, Allah and other names familiar to the Hindus and Muslims, it uses these names in a different context.
Some Bani from the Guru Granth Sahib:
God is the creator of all. “He created air, water, fire, Brahma, Vishnu and Shiva” (Guru Granth Sahib, 504).
“He created Brahma, Vishnu and Shiva, who act according to His Will” (Guru Granth Sahib, 948).
“The performance of countless millions of other devotions is not even equal to one devotion to the Name of God” (Guru Granth Sahib, 1163). “Those who serve Shiva and Brahma cannot find the limits of God” (Guru Granth Sahib, 516).
The ones who serve any other instead of God cannot attain salvation. Salvation is granted only by God. “Everyone must serve the One Lord, who created Brahma, Vishnu and Shiva. O Nanak, the One True Lord is permanent and stable. He does not die, and He is not born” (Guru Granth Sahib, 1130).
By the order of God, Brahma obtained a body. By the order of God, Shiva was born. By the order of God, Vishnu was born. Everything is created by God. God, who made Shiva a yogi. God, who gave Brahma the kingdom of Vedas. God, who has shaped the entire universe. Is the one we salute. They consider that Shiva is God. They are unaware of the Supreme Primal Lord. (Benti Chaupee Sahib).
Sikhi teaches that their is only one God. The Guru Granth Sahib Ji is the Holy Scripture of the Sikhs. Sikhs bow their head in their Gurdwaras to Guru Granth Sahib as a sign of respect but Sikhs do not worship the scriptures. Considered the Eleventh spiritual teacher of the Sikhs which shows the way to meet God.
Extracted from: http://www.sikhiwiki.org/index.php/Vishnu