An MoT tester nodded through 35 vehicles without checks - and four had dangerous parts.
Mechanic Stuart Zabinec received £25 for each bogus deal and was warned in court that he now risked custody.
A Transit van had failed a test 20 days earlier, when 10 faults were spotted, said Olivia McGinn, for the Driver and Vehicle Standards Agency.
"There was corrosion and major structural problems," she told Nottingham Magistrates’ Court .
A Seat Leon had 11 faults, four of which were listed as "dangerous". These had been revealed when it failed an MoT test three weeks before.
The court heard that concerns were raised and computer checks showed that Zabinec, 29, appeared to be issuing certificates when off duty and even while on holiday. He was questioned by officials from the agency.
"He said that he gave them a cursory glance and accepted that it was improper. But he said later that he had not seen the vehicles but issued certificates for £25.
"This went on over a long time with a large number of vehicles. It was also done to the extent of there being dangerous vehicles being used,” said Miss McGinn.
A probation report was ordered on Zabinec, of Clayfields Close, Bulwell.
He admitted seven charges of fraud by falsely claiming to have carried out MoT tests. More than 20 other offences will be taken into consideration.
Euan Edwards, in mitigation, told the court: "It was a massive mistake, a dangerous mistake, a foolish mistake."
But he said that nearly all the offences were revealed because Zabinec co-operated fully with the investigation, showing "real, genuine remorse."
Mr Edwards went on: "He has not sought to water it down in any way. This is extremely serious and a number of people were put at risk. Luckily, nothing happened."
Zabinec lost his job but had now got another one in the industry, said Mr Edwards.
District judge Leo Pyle ordered a probation report on Zabinec and adjourned the case until July 16.
"All options will be available, including immediate custody or a committal to the crown court.
At the moment, I am edging toward the crown court," the judge said.
