ME-SFI alternator interface function - GF07.61-P-3003G
ENGINE 273 in MODEL 463.202/222/236/237 up to 31.5.12 as of model year 2009/YoM 08
Function requirements for alternator interface of the ME gasoline injection and ignition system (motor electronics) (ME), general points
- Circuit 87M ON (engine control ON)
- Engine running
Alternator interface, general points
Messages are exchanged via the LIN over the alternator interface between the alternator and the ME-SFI [ME] control unit and the control response of the alternator is controlled. For this purpose, the ME-SFI [ME] control unit reads the following sensor and signal:
- Crankshaft Hall sensor, engine speed
- Battery voltage (G1) through "circuit. 30"
Alternator interface function sequence
The ME-SFI [ME] control unit regulates the alternator control response, for example in order to reduce the regulation voltage (charging voltage) when the battery is sufficiently charged. This reduces engine load, thus also reducing fuel consumption and improving exhaust gas emissions.
The ME-SFI [ME] control unit controls the following functions:
- Switching on the alternator after engine start.
- Regulation of the alternator according to performance maps stored in the ME-SFI [ME] control unit. To do this, the control voltage is preset by the ME-SFI [ME] control unit.
- Adapting the control voltage with a delay in the event of frequent load changes at the alternator to stabilize the idling speed.
- Protect alternator against overheating.
- Generating a "circuit 61 signal" (alternator in function).
- Report detected faults to the instrument cluster for actuation of the respective warning lamps and display messages.
The alternator continuously performs self-diagnosis and sends the results when requested to the ME-SFI [ME] control unit. This compares the results with other signals (for example, engine rpm, battery voltage, time since engine start) and thus detects any alternator faults.
The following faults are identified:
- Short circuit or discontinuity at output "circuit 61" from ME-SFI [ME] control unit.
- Line for alternator interface (LIN) is interrupted or interface driver in ME-SFI [ME] control unit defective (A regulation voltage of 13.45 to 14.15 V is prescribed for this fault).
- Electrical and mechanical faults at alternator:
- controller or diodes defective
- stator interruption or short circuit
- excitation circuit open
- regulation voltage and charging current not reached
- regulation voltage too high
- cracked or loose poly-V belt
Diagnosis:
In order to check the regulation voltage, the battery must be placed under load using a battery tester since the regulation voltage can be reduced significantly when the battery is fully charged and under no load.
"Circuit 61 signal"
For alternators with an alternator interface, line "terminal 61" is not needed. Using the information received by the ME-SFI [ME] control unit through the alternator interface, the "terminal 61 signal" is simulated in the ME-SFI [ME] control unit and sent through an output stage connected to ground (e.g. for the instrument cluster).
| Instrument cluster, component description | A1 | GF54.30-P-6000G | |
| Component description for ME-SFI [ME] control unit | N3/10 | GF07.61-P-6000G |