Three-year-old Alfie Lamb was allegedly squashed when his mother’s boyfriend Stephen Waterson, 25, twice moved his seat back while he was in the footwell behind.
Nightclub worker Waterson and Alfie’s mother Adrian Hoare, 23, from Croydon, south London, have denied manslaughter.
On Wednesday, jurors were invited to look into the dusty dark blue Audi A4 convertible in the outdoor car park of the Old Bailey.
An officer demonstrated how the front car seat operated and showed off the firmness of the seats.
Each juror took it in turns to peer into the passenger side of the vehicle in silence.
They then wrote down a couple of questions which were passed to the judge Mr Justice Kerr on notepaper.
The judge, court staff and lawyers had abandoned their robes and wigs in favour of warm coats for the 10-minute visit.
Members of the press and public were also allowed to accompany them on the visit.
Earlier, the judge had warned the jury they would not get the chance to carry out a reconstruction of what happened.
He told jurors: “I would ask you during the view to remain silent and not to talk. The purpose of the exercise is for you to see the car.
“It is not a reconstruction of any kind of what happened.”
Jurors have previously heard how Alfie was in the rear footwell by his mother’s legs during a fateful journey from Sutton to Croydon, south London, on February 1 last year.
He screamed and moaned as he was crushed by the car seat, yet Hoare failed to stop it, the prosecution claim.
Alfie was pulled from the car unresponsive and died in hospital days later.
At the hospital, an officer overheard Hoare tell someone on the phone: “Alfie’s going to die. You probably want to come down,” the court heard.
Hoare was also overheard saying: “I’m just waiting for this little shit to wake up now,” according to an officer whose statement was read in court.