The hybrid Escape and Mariner vehicles are full hybrid vehicles, meaning that, at times, the vehicle will run 100% on electric power only. In fact, it is capable of traveling up to 25 mph (40 kph) without ever starting the engine. At times, the engine may shut off at speeds as high as 40 mph (64 kph). Plus, when conditions are right, the engine may shut off at stops and not restart until after 25 mph. As a result, the advertised fuel economy of a full hybrid vehicle is typically much higher for the city driving conditions than the highway driving conditions. In theory, assuming the person's trip was short enough, a person could drive in slow-moving, stop-and-go traffic without using any gasoline at all. How is all of this achieved? And what does it mean to the service technician?

Hybrid Operation Modes
The high-voltage (HV) electric motor and four-cylinder engine will trade off between each other while driving, as well as team up at times to propel the vehicle. The electric motor also plays an equally important role during braking and recharging the vehicle's batteries. The PCM decides when to trade one power source for the other and when to team them up.

Startup
When the key is first turned to the start position, the engine will start. Since there's no conventional electric starter on the vehicle, this action is performed by the 330-volt electric motor located inside the transmission. There's no starter no...