In that case, revealed by the transport ministry, the air bag ruptured when it was launched while the vehicle was being scrapped last month.
The rupture occurred on the passenger side of the now discontinued Will Cypha, company spokeswoman Kayo Doi said.
That air bag problem is not part of the ongoing recalls, and Toyota will add the new case to the company's investigation, she said.
Broken metal fragments were found but nobody was injured at the site, according to Masato Sahashi, a ministry official in charge of recalls.
He said the cause of the rupture was still under investigation.
Transport minister Akihiro Ohta last week ordered Japanese car makers to expedite their current recalls.
The air bag problems have been blamed for at least six deaths and dozens of injuries.
Millions of cars have been recalled worldwide.
About 2.61 million have been recalled in Japan so far, but only about half had been taken care of.
There were four cases of ruptures in Japan but none involved injuries.
-AP