Lil Wayne won four Grammy awards earlier this year
Lil Wayne has appeared in court for a pre-trial hearing over charges of possessing drugs and a handgun on his tour bus in Arizona in January 2008.
The rapper, 26 - real name Dwayne Carter - was arrested at a border checkpoint east of Yuma after police said they found cocaine and ecstasy.
His lawyer, James Tilson, said his request for the training record of a sniffer dog had been rejected.
Mr Carter, who has denied the charges, is due to appear again on 11 August.
Mr Tilson said: "If the dog is not reliable, then that puts the entire probable cause for the stop into question."
He said he would also be pushing to view any video recorded by border cameras on the day Mr Carter was stopped.
His client faces one count of possessing dangerous drugs, one of possessing drugs paraphernalia and one of weapons misconduct.
In March, a judge in Atlanta, Georgia, dropped drug charges against Mr Carter which stemmed from his arrest at a hotel in August 2006.
Earlier this year, the rapper won four Grammy awards including best rap album for last year's Tha Carter III.