ME-SFI maximum engine speed limitation, function - GF07.61-P-3007MOS

ENGINES 275.953 in MODEL 216.376, 221.176 as of Model Year 09 /AEJ 08 

ENGINES 275.982 in MODEL 216.379, 221.179 as of Model Year 09 /AEJ 08 

Function requirements maximum engine speed limitation, general points 

• Circuit 87M ON (engine control ON)
• Engine running

Maximum engine speed limitation, general points 

The maximum engine speed is limited to protect the engine and the drivetrain. The ME control unit (L5) detects the engine speed via the crankshaft position sensor signal (N3/10). The ME-SFI control unit adjusts the maximum engine speed according to the following sensors and signals:

• Crankshaft position sensor, engine speed
• Throttle valve actuator (M16/6), throttle valve position
• ETC control unit (N15/3), selector lever position over the drive train CAN (CAN C)
• ESP control unit (N47-5), vehicle speed over the chassis CAN (CAN E)

The ME-SFI control unit limits the maximum engine speed through the following measures:

• Reduces the opening angle of the throttle valve
• Switching off the fuel injection valves (Y62)

Maximum engine speed limitation, function sequence 

The ME-SFI control unit controls the maximum engine speed in the following conditions:

• Torque converter protection function sequence 
• Driving mode function sequence 
• Throttle valve actuator fault function sequence 
• Missing variant coding function sequence 

Torque converter protection function sequence 

In order to protect the torque converter in selector lever positions P or N (no power flow) from excessive static internal pressure, the maximum engine speed is limited to approx. 4200 rpm. The ME-SFI control unit receives information about the current selector lever position from the ETC control unit over the drive train CAN.

Driving mode function sequence 

In driving mode, in order to protect the engine from inadmissibly high engine speeds, the maximum engine speed is first limited to about 6200 rpm and then, after 10 s, to about 6000 rpm.

The ME-SFI control unit detects the driving mode on the "vehicle speed" CAN signal from the ESP control unit (over the chassis CAN).

Throttle valve actuator fault function sequence 

In the event of a defective throttle valve actuator, the maximum engine speed is limited in idle to approx. 1400 rpm and in driving mode to approx. 1800 rpm.

Missing variant coding function sequence 

If no variant coding exists, maximum engine speed is limited to 2400 rpm.

	Electrical function schematic, maximum engine speed limitation ME	Model 216	PE07.61-P-2757-97CAA
		Model 221	PE07.61-P-2757-97SAA
	ME-SFI [ME] control unit, component description	N3/10	GF07.61-P-6000MOS