Observing sleeping by means of external closed-circuit current measurement

Sporadically or continuously, an increased closed-circuit current or too many wakings can occur in the parked vehicle. Possible causes can be defective peripherals of a control module (sensor, switch, short circuit, etc.) or faulty control modules.
Automatic detection of the cause is not possible on E65-E66 troubleshooting requires an external closed-circuit current measurement to observe the vehicle as it goes to sleep.

Procedure: external closed-circuit current measurement with measurement system

The GT1, DISplus or MIB oscilloscope with 50 A ammeter clip are very suitable for a long-term measurement of the closed-circuit current.

Vehicle preparation:
Before the measurement, the vehicle must be prepared to ensure good results and avoid possible disturbances during the measurement:

Park the vehicle in a position where the measurement can be performed without disruption.
The battery must be adequately charged and the battery charger not connected. If necessary, charge the battery beforehand.
Open the engine bonnet and pull up the engine bonnet contact switch (simulation of closed engine bonnet).
Open the luggage compartment lid and secure the luggage compartment lock with the luggage compartment lid open using a screwdriver or similar (simulation of closed luggage compartment lid).
Switch on a map-reading light (detection of the first consumer shutdown: CS_roof).
Open the glove compartment (detection of the second consumer shutdown: CS_body).
Open the driver's door and close it again (simulation of entry).
Switch on the ignition for at least 5 seconds and then switch it off again. Remove the remote control or identification sensor for vehicles with Comfort Access from the insert compartment and do not leave it in the vehicle.
Open the driver's door again and secure the driver's door lock with the driver's door open using a screwdriver or similar (simulation of exit).
Secure the vehicle.

Setting of the oscilloscope for a long-term measurement:

(1) Activate the recorder mode.
(2) Select 50 A current.
(3) Select the measuring range +10 A.
(4) Select the frequency range: e.g. 0.2 mHz (1 measurement per 10 seconds, resulting in a maximum recording duration of 13.8 hours).
Note: The frequency range determines the recording duration of the measured values and the frequency with which the measured values are recorded. The greater the set frequency, the more frequently a measured value is recorded and the shorter the saved recording duration.
Select the oscilloscope display.
Connect the 50 A ammeter clip to GT1, DISplus or MIB
Note: The 50 A ammeter clip is calibrated in accordance with the instructions on the screen of the relevant diagnosis system during the settings. Here, the 50 A ammeter clip must not be connected to the vehicle.
Note: For all long-term measurements, the GT1 must be on the docking station.
e.g. see below for connection of the 50 A ammeter clip (1) with the 2/3 adapter (2) to the GT1 (3):

Connection of the 50 A ammeter clip on the vehicle:
if the negative battery lead is accessible, connect the 50 A ammeter clip (1) to the negative battery lead (arrow towards the battery); as otherwise, connect the ammeter clip at the positive battery lead (2) to the power module:

Note: The following consumer units are not picked up across the positive battery lead to the power module: alternator, starter, electric fan, secondaray air pump, Valvetronic (petrol engine), common rail (diesel engine).

Observing the vehicle sleeping and troubleshooting

Regular sleeping
The identifying features (see table below) enable tracking of the vehicle's sleeping.

No.	Time	Event	Identifying features
1	0 - 3 min	Reaching the idle state	- Lighting of the START-STOP button goes out. - Lighting of the switch blocks for seat adjustment go out. - Lighting of the child safety switch on the switch block on the driver's door (green LED) goes out
	3 - 16 min	Vehicle sleeping
2	16 - 17 min	PM wakes up the vehicle: shutdown CS_roof	- Map-reading light goes out.
	17 - 60 min	Vehicle sleeping
3	60 min	shutdown CS_body	- Glove compartment light goes out.

Note: If the engine has run for a period of time, two additional wakings are to be observed: 30 min and 70 min after terminal R OFF, KOMBI (instrument cluster) wakes the vehicle to query the coolant temperature. Both wakings are normal and do not lead to a fault memory entry.

First waking by the KOMBI (instrument cluster) (check of the coolant temperature).
Second waking by the KOMBI (instrument cluster) (check of the coolant temperature).

Sleeping with closed-circuit current fault

No.	Event
1	Start of the closed-circuit current monitoring after shutdown of CS_body.
2	Detection of a closed-circuit current fault for 8 minutes.
3	PM wakes the vehicle and, after 90 seconds, switches terminals 30U and 30B off for a few seconds (control module reset). PM saves fault memory entry A158 with the measured closed-circuit current value as additional information.
4	Reset of terminal 30U and 30B: All of the consumer units supplied by the power module except for the instrument cluster, LM, FBD receiver, CAS, DWA and DME/DDE.
5	Closed-circuit current fault still present.
6	PM wakes the vehicle and, after 90 seconds, switches terminals 30U and 30B off for a sustained period for this idle cycle. PM saves fault memory entry A161 with the measured closed-circuit current value as additional information.
7	Shutdown of terminal 30U and 30B: All of the consumer units supplied by the power module except for the instrument cluster, LM, FBD receiver, CAS, DWA and DME/DDE.

In this example, the closed-circuit current fault was still present after the reset of terminals 30U and 30B:

If the closed-circuit current fault is no longer present after shutdown of terminals 30U and 30B, the cause is a control module or component that is connected to one of these two terminals.
In order to pinpoint the cause, run a measurement at the high-voltage outputs on the power module with the ammeter clip. In this way, it can be determined in which area the consumer unit is located: distribution box at front or rear.
At the corresponding distribution box, the cause can be determined by successively removing fuses.
If the closed-circuit current fault is still present after the shutdown of terminals 30U and 30B, concentrate the troubleshooting on the components supplied via terminal 30: KOMBI (instrument cluster), LM, DWA, DME/DDE and FBD receiver.

Sleeping with frequent wakings

No.	Event
1	Authorized wakings: shutdown of CS_roof.
2	Shutdown of CS_body.
3	The power module has registered the more than 30 wakings and switches terminals 30U and 30B off for a sustained period for this idle cycle.

Note:

The vehicle must normally go into the idle state with doors and bonnet/rear lid open!
As a rule, a fault (waking or inhibited sleeping) always keeps all bus systems awake or wakens them!

If the vehicle does not go into the idle state for a sustained period, it must be determined which bus or which control module is waking the vehicle without motivation.

Procedure:

Read out the fault memory and run the test modules for all fault memory entries.
To check which bus system is waking the vehicle, it might be necessary to unpin the corresponding data line of the various bus systems at the gateway (here: SGM-ZGM or ZGM) in order to test.
Identify possible causes by successively disconnecting fuses or disconnecting the corresponding control modules.
In the case of vehicles with the optional extra Easy Access, also disconnect the outside door handle electronics on all door in succession.
After troubleshooting or fault elimination, make sure of the success by putting the vehicle to sleep a number of times and observing behaviour on sleeping!