The invention discloses a torque error detection and torque estimation system. A vehicle may include a powertrain having an engine and a generator coupled to a driveshaft, an inverter configured to provide phase currents to the generator, and a controller programmed to output a fault condition based on first and second generator torques, the first generator torque being based on an engine torque and the second generator torque being based on no more than two phase currents of the generator.