Waking up the vehicle

Registration of the waking in the JBE

K-CAN bus wakings can be recognised by the JBE and allocated to the individual control units. The last 50 CAN messages that woke the K-CAN bus are stored in the energy history memory in the JBE. The relative time from the instrument cluster and the kilometre reading are also stored as marginal conditions.

However, no distinction can be made between authorised and unauthorised wakings.

Note: If the test module is unable to interpret the waking CAN message, ”unknown control unit” is displayed as waking. This can have the following possible causes:

JBE was unable to recognise the waking CAN message properly.
The stored CAN message cannot be allocated to any control unit.

Brief description of components

Waking registration in the junction box electronics

The JBE contains another processor, a so-called co-processor. As the JBE itself 'goes to sleep in the idle state, thus switching off the main process, the JBE would not notice a brief waking.
With the other processor, the K-CAN bus can be permanently monitored and the waking attempts stored in the energy history memory.

System functions

The wakings are recorded in the time span between terminal ”R off” and terminal ”R on”. Due to the electrical processes in the idle state of the vehicle, wakings also occur when the vehicle is fully intact. This means that when these wakings are evaluated the wakings that normally occur are to be taken into account:

Authorised waking

Control unit name	Possible reasons for waking (authorised wakings)
CAS Car Access System	- Operation of the START-STOP button. - Ejection of remote control / identification sensor from the slot. - Operation of the centre lock button. - Operation of the remote control. - Bonnet contact switch. - Door-handle contact, front left and front right. - Wake-up line. - Wake-up line of the TCU (Telematic service). - Telestart of the independent heating function.
CA Comfort Access	- Comfort access
FRM Footwell module	- Consumer unit shutdown. - Door contact, rear left and rear right. - Door contact, front left and front right. - Door lock, front left. - Interior lighting button. - Hazard-warning switch. - Light switch. - Steering-column lever, flashing left or right. - Headlight flasher.
JBE junction box electronics	- Luggage compartment button and luggage compartment lock. Actuating the glove compartment button. - Actuating the parking brake button (the EHB control unit wakes up the vehicle via the wake-up line, but JBE is entered, as EHB is not connected to the K-CAN) - Hotel position switch. - - Wake-up line.
KOMBI instrument cluster	- Query of the coolant temperature at the DME/DDE . - Timeout of the programmed timer for independent heating function, independent ventilation function and independent air-conditioning function.
CHAMP Multimedia Platform or M-ASK Multi Audio System Controller	- Pressing the rotary push button for volume control.
RSE Rear Seat Entertainment	- Pressing the rotary push button for volume control.
IHKA (integrated automatic heating / air conditioning system)	- Actuating the luggage compartment lid button on the centre console switching centre.
FZD Roof Function Centre	- Triggering the acoustic and visual alarm.

Recording wakings

Difference between normal case A and failure frequent waking B (see illustration above).

Terminal R OFF
Waking FRM (8 minutes after terminal R Off): Consumer shutdown only if the vehicle is not locked.
Waking instrument cluster (KOMBI) (40 minutes after terminal R Off): Query of the coolant temperature. Waking does not always occur, only under certain conditions.
Waking instrument cluster (KOMBI) (80 minutes after terminal R Off): Query of the coolant temperature. Waking does not always occur, only under certain conditions.
Authorised wakings: see table above.

Notes for Service department

General information

Troubleshooting in the event of a problem with too many unauthorised wakings

The vehicle is not permitted to wake any of the control units not mentioned above. In the event of errors in the energy diagnosis test module or in the service function for analysis of the waking, they are recognised as unauthorised wakings.

In the event of errors (frequent unauthorised waking), the following possible causes are to be checked:

Defective peripherals of the cause (for example defective sensor or switch).
Defective control unit.
Wake-up cable for causes connected to the PT-CAN (for example, loose contact).

Diagnosis instructions

Observe the instructions in the diagnosis system: energy diagnosis test module and service function for the analysis of wakings.