Coasting function

2.12 Coasting function

The 911 Carrera models now feature the coasting function in conjunction with the Porsche Doppelkupplung (PDK). Coasting refers to operating the vehicle with the engine disengaged, for example on slight downhill gradients; the engine is operated at idle speed so that the function of the auxiliary systems (alternator, air-conditioning compressor, coolant pump, etc.) is maintained.

During coasting, the kinetic and potential energy of the vehicle is directly used to overcome driving resistance. Although no fuel is used during deceleration with deceleration fuel cutoff, the vehicle is significantly decelerated. If no deceleration is desired, additional fuel must be used to cover the lost distance.

Activating and deactivating coasting mode

Coasting mode is activated and deactivated using the Auto Start Stop button.

Deactivating:

• Press button (1) • The indicator light in the button lights up red • Coasting mode is deactivated and automatic stopping of the engine is suppressed

Activating:

• Press button (1) • The indicator light in the button goes off • Coasting mode is activated and the engine is automatically switched off when the vehicle stops

Prerequisites for coasting mode:

• Driving in selector lever position D • Coasting mode is activated (indicator light in the button is off) • Sport or Sport Plus mode is deactivated • PSM is active • Control cruise mode is not active • Engine, transmission and battery have reached operating temperature • Relaxed/economic driving style • Only a slight uphill or downhill gradient • Remove foot slowly from accelerator pedal The engine is disengaged and runs at idle speed. The vehicle rolls with no engine braking effect. Coasting mode can be identified by the tachometer showing idle speed. DME engine electronics 2

1 The Auto Start Stop button switches the Auto Start Stop function on and off and activates and deactivates coasting mode.

DME engine electronics 2

Deactivation of the coasting function

Automatically

With a sporty driving style or if the accelerator pedal is released suddenly, coasting mode is suppressed to allow targeted use of the engine braking effect. Likewise, coasting does not occur on steep uphill gradients since the coasting phase would be very short due to the uphill gradient and no significant fuel saving is possible. Coasting mode is suppressed on steep downhill gradients since the vehicle does not slow down, despite the engine deceleration torque, and the use of deceleration fuel cutoff means that no fuel is consumed in this driving situation.

Manually

• Press the accelerator pedal or • Press the brake pedal or • Press a shifting paddle or a shift button or • Change gears using the selector lever

Activation of the coasting function

If coasting mode is suppressed, for example due to a sporty driving style, sudden release of the accelerator pedal or excessively low engine temperature, it can be initiated manually by shifting up a gear with the shift paddle, one of the shift buttons or the selector lever.