Leclerc was due to be second on the grid behind Red Bull driver Max Verstappen, but the Monegasque went into the formation lap at Turn 6 (Ferradura) and continued between the barriers.
Earlier, a small puff of smoke billowed from the rear of his SF-23 and the car was seen rolling with the rear axle locked. From then on the driver was the passenger.
talking Sky Sports F1Leclerc thinks an engine problem triggered the spin because he later suffered a hydraulic failure that ripped the steering wheel from his hands.
He explained: “When I lost the steering wheel, I basically went straight because I didn’t have hydraulics anymore.
“I don’t think it’s a hydraulic problem. I mean, I know what it is. I can’t go into too much detail.
“Then there was an engine thing that made me lock up the rear wheel and then obviously I spun and hit the wall. I couldn’t do anything.”
Ferrari team-mate Carlos Sainz suffered a hydraulics failure during FP1 at the previous Mexico City round, but Leclerc felt he had seen enough to suspect his problem was “completely different”.
After Sainz blamed a poor ride on a clutch, Leclerc said: “I’m happy with my car, we’re changing the settings between the cars from weekend to weekend.
“I think he was unhappy with what they did next to the garage but I’m on my side it was good.”
Leclerc was initially able to clear the barrier but the front wing was damaged. He then parked an escape route to ensure his retirement.
The Sao Paulo race was quickly red-flagged after a major Turn 1 shunt that wiped out Kevin Magnussen and Alex Albon.
Williams racer Albon moved past Nico Hulkenberg off the line but Haas clipped his rear tire and sent him spinning into Magnussen.
It ripped a tire from the rim, which in turn cloned Daniel Ricciardo’s rear wing, as Magnussen spun behind Oscar Piastre.
Both Australians were able to restart the race from the pitlane, one lap down, as a 25-minute stoppage for barrier repairs allowed the teams to complete repairs.