ME alternator interface function

Commands are exchanged between the ME control unit (N3/10) and the alternator (G2) via the alternator interface for the purposes of alternator control and fault detection.

The alternator interface between the ME control unit and the alternator is provided by the Local Interconnect Network Bus
(LIN).

 Tml. 61 is no longer simulate by the alternator, but by the ME control unit and output via the Control Area Network Bus Class C (engine compartment) (CAN-C).
Tml. 61 is also used for actuation of the multifunction display (A1p13) in the instrument cluster(A1).

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The alternator is controlled according to the presets for regulation voltage and current control.

The following functions are possible:

 Alternator activation following engine start

 Delayed alternator activation following engine start (engine 266.920 only: with a fully charged battery (G1) the alternator is activated with a delay following the engine start under some circumstances)

 Alternator cut-off to stabilize idle speed

 Alternator cut-off to increase vehicle dynamics

 Alternator cut-off to protect alternator from overheating

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 Alternator cut-in to increase electrical load in overrun

 Alternator cut-in to prevent undervoltage

Additional information is read in by the ME control unit for self-diagnosis of the alternator, and compared with the engine speed, battery voltage and time following engine start and the following functions carried out:

 Detection of faults

 Storage of faults

 Display of faults

The following alternator communication errors are detected following "Ignition On" and displayed as a fault entry in the multifunction display of the instrument cluster:

 Alternator interface defective.

 Line interruption (tml. 30)

The following alternator communication errors are detected following "Engine Start" and displayed as a fault entry in the multifunction display of the instrument cluster:

 Electrical fault at alternator

 Mechanical fault at alternator

 Line interruption (tml. 30)

 Undervoltage and defective alternator interface