Reduce Consumers, Basic Function - GF54.10-P-1011A
Model all (CAR)
Overview
This document contains the following information:
- General
- Consumer reduction
General
Switching off or shutting down various functions relieves the load on the 12 V on-board electrical system, if the required electrical power can no longer be supplied. This serves to avoid any significantly negative charge balance for the on-board electrical system battery while also guaranteeing vehicle mobility.
Consumer reduction
Consumer reduction is activated when one of the following conditions occurs:
- The on-board electrical system voltage drops to a defined value.
- A high load is detected at the power source supply (alternator or DC/DC converter).
- The maximum discharge current of the on-board electrical system battery has been reached. The maximum value here depends on the charge level of the on-board electrical system battery.
The first consumer's power consumption level is reduced at the earliest 5 s after the system start. If the cutback conditions remain unchanged, the power consumption of one further consumer will be reduced or shut down every following second.
Vehicles with PRE-SAFE® system
PRE-SAFE® measures have a high energy requirement. Therefore when they are triggered, several high-performance consumers are quickly reduced or shut down for the duration of the measures.
Vehicles with 48 V technology, hybrid vehicles or electric vehicles
The energy requirement is provided by the transfer of energy from the 48 V or high-voltage on-board electrical system. If the state of charge of the 48 V battery or the high-voltage battery drops below a defined limit value, energy is no longer transferred.
Various functions are derated or switched off depending on the vehicle equipment involved.
Consumer reduction for comfort functions (equipment-dependent)
| Sequence | Function with power reduction or one that can be switched off |
|---|---|
| 1 | Wiper park heater |
| 2 | Refrigerator box |
| 3 | Washer fluid heater |
| 4 | Mirror heater Head space heating stage 3 |
| 5 | Rear window heater |
| 6 | Steering wheel heater Head space heating stage 2 |
| 7 | Trunk socket |
| 8 | Residual heat utilization Head space heating stage 1 |
| 9 | Stationary heater |
| 10 | Taxi roof sign |
| 11 | Telematics/audio/telephone/GPS Ambiance illumination |
| 12 | Presafe function Drivetrain consumers |
At the same time as the actions in the above table, the output of the air conditioning and seat heating is restricted to match the current status of the on-board electrical system.
The alternator management prevents the battery from being discharged specifically for recuperation purposes as long as the on-board electrical system voltage is below a defined value.
If none of the triggering conditions are met, consumer reduction is canceled. The switched-off consumers or functions are switched-on again in the reverse order with a waiting time in each case of 1 s. With circuit 15R OFF, and depending on the charge level of the on-board electrical system battery, various consumers (e.g. telematics, stationary heater, standing light) are switched off, but not in a specific sequence.
| Function schematics | |||
| Consumer reduction, function schematic | Model 118, 177, 243, 247 | PE54.10-P-2501-97A | |
| Model 167, 293 | PE54.10-P-2501-97B | ||
| Model 213, 238, 257, 290 as of model year 2021 | PE54.10-P-2501-97C | ||
| Model 223 | PE54.10-P-2501-97D | ||
| Model 206 | PE54.10-P-2501-97E | ||
| Model 297 | PE54.10-P-2501-97F | ||
| Control units | |||
| Basic function of signal acquisition and actuation module | Model 118, 177, 243, 247 Model 118, 177, 247 |
GF54.21-P-9895A | |
| Basic function of signal acquisition and actuation module at front | Model 167, 206, 223, 293, 297 Model 213, 238, 257, 290 as of model year 2021 |
GF54.21-P-9896A |