The Triple Eight Race Engineering driver went off between Turn 13 and Turn 14 on his fourth lap of the Adelaide Parklands Circuit after a shock failed entering the right-hander.

The driver of the #11 Holden ZB Commodore was uninjured and the team is assessing whether the car is repairable.

“Something failed,” Walls told Supercars.com.

“Not really sure what happened. It’s pretty annoying. But, we’ll investigate, we’ll figure out what went wrong.

“Hopefully we can get it out for the rest of the weekend, but we’ll have to wait and see.”

The crash brought out the red flag and reduced proceedings by roughly 10 minutes.

Walls entered the final round of the Super2 Series as the leading rookie, ahead of teammate Ben Gomersall and Cody Burcher.

Walls is fifth overall and the top Holden driver this season behind the dominant Tickford Race quartet of Rylan Gray, Lochie Dalton, Nash Morris, and Reuben Goodall.

Gray was quickest in the first practice session with a 1:20.9265s in his Ford Mustang, leading stablemate Goodall.

Jordyn Sinni was third while Cameron McLeod and Brad Vaughan set the exact same time to share fourth.

NASCAR Xfinity Series winner Jesse Love was 22nd and 2.4 seconds off the pace of Gray.

Practice 2 for the Dunlop Super2 Series takes place on Thursday afternoon at 2pm ACDT.

Results: Dunlop Super2 Series BP Adelaide Grand Final, Practice 1