Jasper Juinen / AP

Floyd Landis tested positive for a high ratio of testosterone and is likely to lose his Tour de France victory.

The results of the second test come just two weeks after Landis, a 30-year-old former mountain biker, proudly stood atop the winner’s podium on the Champs-Elysees, waving to thousands who cheered him on.

Within 45 minutes of the “B” sample announcement, the Swiss-based team Phonak fired its captain for “violating the teams internal Code of Ethics.”

Phonak stood by Tyler Hamilton throughout his blood-doping case two years ago; Landis, however, is getting no support.

“This will be his personal affair, and the Phonak team will no longer be involved,” a statement said.

Testosterone, a male sex hormone, helps build muscle and improve stamina. The urine tests were done July 20 after Landis’ Stage 17 victory during a grueling Alpine leg, when he regained nearly eight minutes against then-leader Pereiro — and went on to win the three-week race.

Both of Landis’ “A” and “B” samples turned up a testosterone/epitestosterone ratio of 11:1 — far in excess of the 4:1 limit.

Jacques De Ceaurriz, the Chatenay-Malabray chief, said the synthetic testosterone was found in isotope testing.

“It’s foolproof. This analysis tells the difference between endogenous and exogenous,” he told the AP. “No error is possible in isotopic readings.”

Landis spokesman Michael Henson disputed that, and the cyclist’s attorney, Spanish lawyer Jose Maria Buxeda, said, “It doesn’t end here.”

Landis and his defense team have offered various explanations for the high testosterone reading — including cortisone shots taken for pain in Landis’ degenerating hip; drinking beer and whiskey the night before; thyroid medication; and his natural metabolism.

Another theory — dehydration — was rebuffed by anti-doping experts.

“It’s incredibly disappointing,” three-time Tour winner Greg LeMond said by phone from the starting line at the Pan Mass Challenge in Sturbridge, Mass. “I don’t think he has much chance at all to try to prove his innocence.

“When I heard it was synthetic hormone, it is almost impossible to be caused by natural events. It’s kind of a downer,” said LeMond, the first American to win the Tour. “I feel for Floyd’s family. I hope Floyd will come clean on it and help the sport. We need to figure out how to clean the sport up, and we need the help of Floyd.”

Slideshow   The Week in Sports Pictures The Giants on top of the football world, getting ready for the London Olympics and more. more photos

In Murrieta, Calif., where Landis lives, an AP reporter was asked by police to leave the gated community when she attempted to approach his house. Several cars were parked in front, and the blinds were drawn.

A man who said he was a friend of the family, but didn’t want his name used, answered the phone at the Landis’ house and confirmed the cyclist was there.

Despite the latest test results, a sign at a nearby freeway exit said, “Welcome Home Floyd Landis, 2006 Tour de France Winner.”

In Lancaster County, Pa., where Landis was raised in a conservative Mennonite home, neighbors vowed their support.

“All he has accomplished, he has attained through his hard work and discipline. We are very confident he will prove his innocence,” said Tammy Martin, a longtime family friend.

Paul and Arlene Landis, who have supported their son since the doping scandal began, were out of town on a previously scheduled vacation.

A sign posted on their front yard said, “God Bless, Went Camping.”