S07.10-0054-79
Block diagram |
A1/1 | Instrument cluster (KI) control unit | CAN E | Chassis CAN | |
B70 | Crankshaft Hall sensor | CAN HMI | User interface CAN | |
B95 | Battery sensor | CAN V | Vehicle CAN | |
G2 | Alternator | LIN C3 | Drivetrain LIN | |
N3/28 | CDI control unit | A | Mercedes-Benz | |
N50 | Fuse and relay module control unit (SRM) | B | Nissan | |
N93 | Central gateway (CGW) | C | Default | |
N127 | Drivetrain control unit | D | Optional |
Function requirements for the alternator interface, general points
Circuit 87 ON (engine management ON)
Engine running.
Alternator interface, general points
With the alternator interface, information is exchanged between the alternator (G2) and the CDI control unit (N3/28) via the powertrain LIN (LIN C3).
Function sequence for alternator interface
The status of the alternator is sent via the alternator interface to the CDI control unit.
The powertrain control unit (N127) receives the status of the on-board electrical system battery (G1) from the battery sensor (B95) and sends this to the CDI control unit.
The CDI control unit also receives the engine speed from the crankshaft Hall sensor (B70).
The CDI control unit sends the "engine running" signal and alternator request to the fuse and relay module control unit (SRM) (N50). This then prescribes the specified voltage to the alternator.
Delayed adaptation of the charging voltage occurs in the event of frequent load changes of the alternator when in idle to stabilize the idle speed.
The alternator constantly performs self-diagnosis. The results are sent via the alternator interface to the CDI control unit. This compares the results with additional signals (e. g. engine speed, on-board electrical system battery voltage, time after engine start) and detects alternator faults based on this.
The following faults are identified:
Control or diodes defective
Stator interruption or short circuit
Excitation interruption
Charging voltage or charging current too low
Charging voltage too high
A cracked or loose poly-V-belt
The CDI control unit sends recognized errors to the instrument cluster (IC) control unit (A1/1), which then issues the corresponding message.