Deactivating the 48 V electrical system
- Deactivate the 48 V electrical system by opening the hood.
The deactivation takes place automatically.
Determining the 48 V electrical system is de-energized
A display of the absence of voltage (48 V electrical system switched off) in the additional electrical storage is only displayed in PAD mode.
Check
- Press the start-stop button quickly 3 times without stepping on the brake pedal to establish the PAD mode.
- Check that the instrument cluster (KOMBI) is de-energized in PAD mode.
Desired state
- The Check Control message "48 V electrical system switched off." Or "Electrical additional storage switched off." (1) is displayed.
Result
» Lack of voltage cannot be determined with the Check Control message "48 V electrical system switched off." Or "Electrical additional storage switched off." (1). Work start is not permitted.
Measure
- Repeat the "deactivate 48 V electrical system" service function.
- Vehicle management > service function > voltage supply > deactivate 48 V electrical system
Only if the Check Control message "48-volt on-board network switched off." Or "Electrical additional storage switched off." (1) is displayed in the instrument cluster (KOMBI), the 12V battery may be disconnected.
Result
» Lack of voltage cannot be determined with the Check Control message "48 V electrical system switched off." Or "Electrical additional storage switched off." (1). Work start is not permitted.
Measure
Switch additional storage with fault memory entry Relay jammed closed to zero potential
Result
» The Check Control message reports that 48 V electrical system is switched off.
Measure
- Exit PAD mode by pressing the start-stop button once without stepping on the brake pedal.
Precondition
Ignition is switched off.
Risk of short circuits! Risk of fire!
- Make sure that there is no battery charger connected to the jump start terminal in the engine compartment.
- For vehicles with additional electrical systems (48 V electrical system, high-voltage vehicle electrical system), this absolutely must be deactivated before the vehicle battery is disconnected.
Risk of short circuits! Risk of fire!
- Make sure that there is no charger connected to the jump start terminal in the engine compartment.
Damage to the 48-V battery
If a 48-V battery disconnected from the on-board electrical system is activated, the battery electronics are damaged.
- Only ever activate the 48 V electrical system when the 48 V battery is fully connected up.
- Deactivate the 48 V electrical system by opening the hood.
Deactivation is automatic.
Check
A display of the absence of voltage (48 V electrical system switched off) in the additional electrical storage is only displayed in PAD mode.
- Press the start-stop button quickly 3 times without stepping on the brake pedal to establish the PAD mode.
- Check the de-energized state in the instrument cluster (KOMBI) in the PAD mode.
Desired state
- The Check Control message "48 V electrical system." switched off (1) is displayed.
Result
» Absence of voltage cannot be specified with the Check Control message "48 V electrical system switched off." (1). Work start is not permitted.
Measure
- Repeat the "deactivate 48 V electrical system" service function.
- Vehicle management > service function > voltage supply > deactivate 48 V electrical system
Only if the Check Control message "48 V electrical system switched off." (1) is displayed in the instrument cluster (KOMBI), the 12V battery may be disconnected.
Result
» Zero potential cannot be determined with the Check Control message "48 V electrical system switched off." or "Electrical additional storage switched off." (1). Start of work is not permitted .
Measure
Switch additional storage with fault memory entry Relay jammed closed to zero potential
Result
» The Check Control message reports that 48 V electrical system is switched off.
Measure
- Exit PAD mode by pressing the start-stop button once without stepping on the brake pedal.
"Disconnect the negative battery cable of the 48-V battery" work can be started.
- Unlock and disconnect the CAN bus plug connection (1) of the gear sensor.
- Release the clip (2).
- Loosen nut (1).
- Detach the negative battery cable (2) of the 48-V battery from the negative battery terminal, set to one side and secure.
Risk of short circuits! Risk of fire!
- Cover the vehicle battery.
- Cover the vehicle battery with the special tool 2 452 007 as shown.
- Position the battery ground lead (1) as shown.