The accusations against the ad, starring popular puppet Abla Fahita, come shortly after the government designated the Brotherhood a terrorist organisation.
The government accused the Brotherhood of orchestrating a series of attacks by Sinai militants, but has provided little evidence of the connection.
The Brotherhood denies the accusations.
Ahmed “Spider”, a self-style youth activist known as a strong supporter of ousted President Hosni Mubarak, says code about an upcoming attack is included in the ad.
In it, Fahita and her daughter Karkoura search for her deceased husband’s sim card, while explaining to her friend over the phone about another character, Mama Touta.
In the background, a radio anchor explains how to make “stuffed turkey” for Christmas while sitting next to a cactus from which ornaments were dangling. She says she asked the building guards to get a sniffer dog of a shopping mall to search for missing things and gets money in return.
Spider explained the alleged code on the Al-Tahrir network: The mall and the dog refer to the planned site of the attack, and Mama Touta is the Brotherhood’s secret name.
“The dog, garage, guard, mall... these elements tell us that there will be a big mall and an explosion after a dog fails to find the bomb in a car,” he said.
Spider said he filed a complaint with Egypt’s prosecutor general, who referred it to state security prosecutors who handle terrorism and other political allegations.
His lawyer told another TV network, el-Faraeen, that an ornament on the cactus refers to the bomb.
A statement by Vodafone said that the prosecutors summoned the company representatives and asked about the accusations, but did not make any accusations themselves.