GF07.10-P-1014OGG Deceleration Fuel Shutoff Function

GF07.10-P-1014OGG Deceleration Fuel Shutoff Function
- as of model year 09

Function requirements for deceleration fuel shutoff, general points
^ Circuit. 87 ON (engine control ON)
^ Engine running
^ Vehicle rolling
^ Accelerator not operated
^ Selector lever position "D" or "R"
^ Vehicle is not cruise control mode

Deceleration fuel shutoff, general points
Deceleration fuel shutoff ensures that the drive wheels transmit a braking torque to the engine via the transmission. This increases the braking effect of the engine (engine brake).

The CDI control unit (N3/9) performs a deceleration fuel shutoff according to the following sensors and signals:
- Coolant temperature sensor (B11/4)
- Accelerator pedal sensor (B37), accelerator pedal position
- Crankshaft Hall sensor (B70), engine speed
- Electric controller unit (VGS) (Y3/8), shift stage over the engine compartment CAN (CAN C)

Deceleration fuel shutoff function sequence
If the accelerator pedal is not actuated (zero quantity delivery), deceleration mode is triggered. The CDI control unit switches off the fuel injectors (Y76) in deceleration mode dependent on the coolant temperature, the engaged gear and for a motor speed >1600 rpm.

The CDI control unit also lowers the fuel pressure in the rails through the quantity control valve (Y94) and the pressure regulator valve (Y74).
If the accelerator pedal is depressed again or the engine speed falls below 1100 rpm, the CDI control unit re-actuates the fuel injectors and increases the fuel pressure in the rails via the quantity control valve and the pressure regulator valve.