Deceleration fuel shutoff, function - GF07.10-P-1014OGG

ENGINES 642.8 in MODEL 164.1 as of model year 2009/YoM 08 model refinement package 

ENGINES 642.8 in MODEL 164.8, 251.1 as of model year 2009/YoM 08 

ENGINES 642.8 in MODEL 251.0/1 as of model year 2011/YoM 10 model refinement package 

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 causes the drive wheels to 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 based on 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 

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 an engine speed >1600 RPM.

The CDI control unit also lowers the fuel pressure in the rails through the quantity control valve (Y94) and the pressure regulating 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.

	Electrical function schematic for deceleration fuel shutoff	Model 164	PE07.10-P-2714-97MAA
		Model 251	PE07.10-P-2714-97RAA
	Component description for CDI control unit	N3/9	GF07.16-P-6000OGU
	Component description for fully integrated transmission control unit	Y3/8n4	GF27.60-P-5165AHZ