GF07.61-P-3007MIK ME-SFI Maximum Engine Speed Limitation, Function

GF07.61-P-3007MIK ME-SFI Maximum Engine Speed Limitation, Function
- refinement package
- as of model year 09


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. Through the signal from the crankshaft Hall sensor (B70), the ME-SFI control unit (N3/10) detects the engine speed. The ME- SFI control unit adjusts the maximum engine speed according to the following sensors and signals:
- Crankshaft Hall sensor, engine speed
- Throttle valve actuator (M16/6), throttle valve position
- Electric controller unit (VGS) (Y3/8), selector lever position over the engine compartment CAN (CAN C) (for automatic transmission)
- ESP and BAS control unit (N47-5), vehicle speed over the engine compartment CAN

The ME-SFI control unit limits the maximum engine speed through the following measures:
- Reduces the opening angle of the throttle valve
- Shifts the ignition angle of the ignition coils (T1) towards "retard"
- Cutout of 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 (for automatic transmission)
^ Manual transmission protection function sequence (for manual transmission)
^ Driving mode function sequence
^ Throttle valve actuator malfunction function sequence
^ Missing variant coding function sequence

Torque converter protection function sequence (for automatic transmission)
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 the indication of the current selector lever position over the engine compartment CAN from the electric controller unit (VGS).

Manual transmission protection function sequence (for manual transmission)
To prevent damage to the manual transmission, the maximum engine speed is limited to about 4000 rpm when the vehicle is stationary.

Driving mode function sequence
In order to protect the engine from inadmissible engine speeds during driving mode, the maximum engine speed is limited to about 6000 rpm.
Driving mode is detected through the "vehicle speed" CAN signal from the ESP control unit over the engine compartment CAN.

Throttle valve actuator malfunction 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.