At first glance, the prototype doesn't seem any different from the standard Honda CR-V rival. However, closer inspection reveals a disguised opening on the right-hand side of the car – the opposite side of where the fuel filler cap resides – a classic tell that a charging port is lurking underneath.
The test hack is also towing what looks like dynamometer equipment, another traditional sign of a new powertrain under development.
While Toyota is unable to officially comment, it's most likely that a PHEV RAV4 would continue to use the 2.5-litre Atkinson cycle four-cylinder petrol engine mated to a larger electric motor and lithium ion battery pack.
While the Japanese maker already has a PHEV in its arsenal in the form of the Prius Plug-in, that 1.8-litre unit is unlikely to provide sufficient power and torque levels to account for the substantial weight increase usually seen with a plug-in hybrid - for reference, the straight hybrid model already weighs around 1750kg.