Ralf Schumacher says Renault may have been getting a "big advantage" from an automated brake bias system that is now under FIA scrutiny.
After Suzuka, Racing Point lodged a 12-page dossier protesting what it claims is French rival Renault's "pre-set lap distance-dependent brake bias adjustment system".
The ECUs and steering wheels used by Nico Hulkenberg and Daniel Ricciardo in Japan were seized and an investigation launched.
The consequences for Renault could be dire.
Former F1 driver Ralf Schumacher told Sky Germany that disqualification from the championship and a fine like the $100 million one given to McLaren for the 'Spygate' scandal are possible.
But he hopes Renault did not deliberately cheat.
'A big advantage'
"As a works team that would be very questionable. They'd have to rethink everything," said the German.
At the very least, he thinks an automatic brake balance system would give the drivers a clear advantage.
"The driver is normally responsible for adjusting the brake balance, so if it is happening automatically you could brake later and take more speed into each corner. It would be a big advantage," Schumacher said.
"An automatic system controlled electronically could do it much better and faster than the driver can manually."
Schumacher thinks there is a big risk that Renault will be found guilty of wrongdoing.
"The suspicion must be reasonable because it's an unwritten rule that you don't accuse another team of something like that unless you're 100% sure.
"If they're right, it's a catastrophe for Renault. And it's not the first time they've attracted attention," he said.
Schumacher is referring to Singapore, where Ricciardo was excluded from qualifying when his MGU-K exceeded the maximum allowed power flow limit.
But he thinks it could be some time before the new controversy is settled.
"The FIA already seems overwhelmed with the simplest decisions, and this is a mammoth task. They need to be completely sure because it would be a huge setback for Renault," said Schumacher.