Verizon on Wednesday updated a lawsuit it filed in March to accuse more companies of making illegal telemarketing calls regarding car warranties. OnStar also joined Verizon in the suit, which now targets nine companies in total.

OnStar provides vehicle-based consumer assistance. Users received more than 400,000 telemarketing calls earlier this year, most of which were automatically answered by OnStar's equipment. Since OnStar handles emergency calls, all calls must be answered, so the influx of calls affected the system, Verizon said.

"These telemarketers continue to prey on our customers using illegal methods to reach them on their wireless phones," Steven E. Zipperstein, vice president and general counsel at Verizon Wireless, said in a statement. "This litigation is aimed not just at the telemarketers, but also at those who enable their unlawful conduct with technological assistance. We will not rest until they stop invading our customers' privacy."

Since January 2008, more than 2 million Verizon Wireless customers have received calls from numbers starting with 281, 614, 801, and 562 area codes.

Those who answer their phones hear a pre-recorded voice that tells them their car warranties are about to expire, and requests that they press 1 for more information. They are then directed to an operator who asks them for the make and model of the car, but if callers ask questions, the call is disconnected.

In February, St. Louis-based National Auto Warranty Services and Florida-based Explicit Media, doing business as Voice Solutions, were forced to pay a $50,000 fine for making these telemarketing calls to Verizon customers. Verizon donated the funds to actress Mariska Hargitay's Joyful Heart Foundation.