Deceleration Fuel Shutoff, Function - GF07.10-D-1014HD

ENGINES 651.955/956/957 in MODEL 906 

with CODE (XZ1) Model generation 1 

with CODE (MZ0) Blue EFFICIENCY 

Function requirements 

• Circuit 87M ON (engine control ON)
• Circuit 61 ON
• Vehicle rolling
• Accelerator not operated
• Selector lever position "D" or "R"
• Vehicle is not in cruise control mode

General 

Deceleration fuel shutoff causes the drive wheels to transmit a braking torque to the engine via the respective transmission. In this way the braking effect of the engine is increased.

The CDI control unit (N3/28) performs a deceleration fuel shutoff based on the following sensors and signals:

• Coolant temperature sensor (B11/17)
• Accelerator pedal module (B37/3) (for model 906), accelerator pedal position
• Crankshaft sensor (L5/10), engine speed
• ETC control unit (N15/3), stage

Function sequence 

The CDI control unit in decel mode switches off the following injectors for a unactuated accelerator pedal dependent on the coolant temperature, the engaged gear and for a motor RPM > 1600/RPM:

• Cylinder 1 injector (Y76/14)
• Cylinder 2 injector (Y76/15)
• Cylinder 3 injector (Y76/16)
• Cylinder 4 injector (Y76/17)

The CDI control unit also lowers the fuel pressure in the rail through the quantity control valve (Y94/3) and the pressure regulating valve (Y74/5).

If the accelerator pedal is depressed again or the engine speed falls below 1600 RPM, then the so CDI control unit re-actuates the fuel injectors and increases the fuel pressure in the rail via the quantity control valve and the pressure regulator valve.