GF07.61-P-2007CY ME-SFI Idle Speed Control, Function

GF07.61-P-2007CY ME-SFI Idle Speed Control, Function
- up to model year 08


The throttle valve actuator (M16/6) regulates the idle speed by adjusting the throttle valve position. It is actuated by the motor electronics control unit (N3/10).
To assist idle speed control, the ignition angle can be retarded by as much as a 36° crank angle and advanced by as much as a 20° crank angle.

Corresponding to its input signals the ME-SFI [ME] control unit controls the idle speed in the warm-up phase and for different engine loads (e.g. gear range engaged, A/C compressor (A9) switched on).

Warm-up phase (heating speed)
In order to bring the catalytic converters to operating temperature more quickly, the idle speed is raised to approx.1100 to 1300 rpm for approx. 20 seconds if:
^ Coolant temperature <40 °C
^ Engine start has occurred

After this time elapsed, the idle speed is increased at a coolant temperature <70 °C depending on the temperature for about 50 seconds by about 50 to 100 rpm.
The increase will be canceled when a gear range is engaged.

with automatic transmission 722.9
When a drive position is engaged, a lower engine speed is controlled in order to reduce the creeping tendency of the vehicle.
The information "Gear range engaged" is conveyed to the ME-SFI [ME] control unit via the drive train CAN (CAN C) by the electronic selector lever module control unit (N15/5).

For manual transmission 716.6
When actuating the clutch pedal the idle speed is stabilized. The operation of the clutch pedal is detected by the ME-SFI [ME] control unit through the clutch pedal switch (S40/3).

Refrigerant compressor (A9)
So that at idle the engine speed does not drop when the A/C compressor is switched on, the automatic air conditioning control and operating unit (N22/7) transmits a signal to the ME-SFI [ME] control unit via the interior CAN (CAN B) and chassis CAN (CAN E) before the A/C compressor is switched on. This responds by adjusting the idle speed appropriately.

Undervoltage of on-board electrical system battery (G1)
If the ME-SFI [ME] control unit detects an undervoltage, the idle speed is increased until the ignition is switched off for the driving mode selected at around 100 rpm.

Adjusting the ignition angle enables a faster response than adjusting the throttle valve.

The basic setting of idle speed can be influenced with the DAS [Diagnosis Assistance System]