Overview
- In early October at the Malaysia Grand Prix, many 2026 cars stalled on the formation lap after heavy rain because new hybrid power‑unit software and wet‑weather settings prevented normal acceleration, forcing a start delay of more than 90 minutes.
- The FIA opened an investigation after that incident and has since required measures and checks intended to stop a repeat of software‑related stalls in wet conditions.
- Rain is forecast for the São Paulo weekend, which renews scrutiny of the 2026 hybrid software and wet settings and heightens the chance that teams will have to prove the fixes during practice and qualifying.
- Drivers offered cautious reassurance in pre‑race media: Max Verstappen joked he had installed an 'antivirus' and told teammate Arvid Lindblad not to worry, while Fernando Alonso said he believes the Malaysia problems have been understood and repaired; Verstappen also noted lingering shifting and radio niggles but said radio was better in Mexico.
- What to watch at Interlagos are team software patches, how cars behave on the formation lap in wet conditions, and race control communications because any repeat stall would affect driver safety and could again delay or disrupt the race weekend.