GF54.10-P-1050LE Engine Off Energy Management, Function

GF54.10-P-1050LE Engine Off Energy Management, Function

General function requirements
^ Circuit 61 OFF (engine OFF)

The circuit status of circuit 61 is made available on the chassis CAN (CAN E) by the CDI control unit (N3/9) (with diesel engine) or by the ME-SFI [ME] control unit (N3/10) (with gasoline engine) and forwarded by the central gateway control unit (N93) to the front SAM control unit with fuse and relay module (N10/1) via the interior CAN.

Special feature of hybrid cars:
The circuit status of circuit 61 continues to be output at automatic engine stop (engine OFF).

Engine off energy management, general
Engine off energy management ensures the stability of the onboard electrical system and the starting capability of the vehicle when the engine is off.
This functionality is integrated in the front SAM control unit and serves to extend the service life of the on-board electrical system battery (G1). To this end, active electrical consumers may be switched off.

Engine off energy management comprises the following subfunctions:
^ Consumer shutoff function sequence
^ No-load current management function sequence
^ Assisted charging/jump start, function sequence

Additional function requirements for consumer shutoff
^ Circuit 15 ON or Circuit 15R ON
^ On-board electrical system emergency mode not active

Status of circuit 15 is provided by EIS [EZS] control unit (N73) on interior CAN (CAN B).

Consumer shutoff function sequence
When the on-board electrical system voltage falls below U = 12.2 V, the consumer shutoff function is activated under the following conditions:
- Engine OFF (circuit 61 OFF)
- Change from circuit 15 ON to circuit 15R ON

Given constant shutoff conditions, one consumer will be shut off every t = 5 s in addition to the consumer reduction from the engine on energy management function.
The shutoff sequence is shown in the following table.

The list includes those consumers whose power supply is reduced or cutoff as part of the "engine on" energy management function.

Steps 1-25:

Even when the on-board electrical system voltage is stabilized at a value above
U = 12.2 V, consumer shutoff is not revoked. Power is only returned to the shutoff consumers following a reset, which is performed by turning the transmitter key (A8/1) to circuit 15C.

Additional function requirements for no-load current management
^ Transition from circuit 15R to terminal 15C

The electronic ignition lock control unit sends the status of circuit 15 via the interior CAN to the front SAM control unit.

No-load current management function sequence
No-load current management ensures the starting capability of the vehicle. No-load current management is integrated in the front SAM control unit and serves to extend the service life of the on- board electrical system battery.

The no-load status is assumed with circuit 15 OFF and with vehicle locked t = 5 min or with vehicle unlocked t = 30 min after the last action or actuation.
For this purpose, power may be cut off to the consumers on circuit 30g through actuation of the no-load current shutoff relay (F32k2).
No-load current management tolerates an increase in energy consumption for a certain time period (e.g. t = 75 min). This allows, for example, the radio to be played while the car is being washed.

Following a period of t = 6 h, or as soon as the on-board electrical system's voltage values drop below certain limits and compromise the starting capability of the vehicle, the extended run-on monitoring function initiates the following actions:
- Open no-load current shutoff relay
- Activate no-load current shutoff via Controller Area Network (data bus/CAN Bus) (CAN)

No-load current management comprises the following subfunctions:
^ No-load current shutoff function sequence
^ No-load current diagnosis function sequence

No-load current shutoff function sequence
The no-load current shutoff function comprises the following subfunctions:
^ Request consumer shutoff function sequence
^ Shut off consumers function sequence
^ Energize consumers function sequence

Request consumer shutoff function sequence
During the transition from circuit 15R to circuit 15C, the vehicle goes into the "vehicle rest" operating state. The timer counting down to no-load current shutoff is then started (waiting time t = 6 h).
The no-load current is continuously monitored by the battery sensor (B95).

If the no-load current is too high, the no-load current shutoff relay will be opened after t = 75 min.
The data from the battery sensor is read in and evaluated by the front SAM control unit via the on-board electrical system LIN (LIN B7).
If during the waiting time the on-board electrical system voltage falls to U < 12.2 V, the no-load current shutoff relay will be opened early.

With U < 12.2 V, the battery sensor will go into sleep mode (reduced power consumption).

At t = 5 min after circuit 15 OFF with vehicle unlocked or after t = 30 min with vehicle locked, the front SAM control unit sends a shutoff signal to the appropriate control units via the interior CAN as advanced notification before the no-load current shutoff relay is opened.
This shutoff signal is relevant to all control units receiving power via circuit 30g.

The following control units receive the shutoff signal via the interior CAN:
- Panoramic sliding roof control module (A98) (Model 221.1 with code (413) Panoramic glass sunroof with top sliding sunroof )
- Multicontour seat pneumatic pump (M40) (with code (409) Left/right front multicontour seats)
- Pneumatic pump for dynamic seat control (M40/1) (with code (432) Left and right dynamic multicontour seat)
- AAC [KLA] control unit (N22/1)
- Rear control unit (N22/6) (model 216)
- Rear seat control unit (N25/6) (model 221 with code (223) Rear seat bench with electrically adjustable outer seats with PRE-SAFE positioning function for outer seats and outer head restraints or with code (276) Memory in rear or with code (402) Rear comfort seats incl. seat heating and seat ventilation or with code (872) Electrically heated left and right rear seats)
- Trailer recognition control unit (N28/1) (Model 221 with code (550) Trailer hitch)
- left front seat control unit (N32/1)
- right front seat control unit (N32/2)
- Left front multicontour backrest control unit (N32/15) (with code (409) Left/right front multicontour seats )
- Right front multicontour backrest control unit (N32/16) (with code (409) Left/right front multicontour seats )
- Left front dynamic seat control unit (N32/19) (with code (432) Left and right dynamic multicontour seat)
- Left rear multicontour backrest control unit (N32/20) (Model 221 with code (406) Multicontour seats in rear)
- Right rear multicontour backrest control unit (N32/21) (Model 221 with code (406) Multicontour seats in rear)
- Right front dynamic seat control unit (N32/22) (with code (432) Left and right dynamic multicontour seat)
- PTS control unit (N62) (with code (220) PARKTRONIC or code (230) Exclusive parking assist)
- Reversing camera control unit (N66/2) (with code (218) Reversing camera and code (498) Japan version)
- Overhead control panel control unit (N70)
- WSS (Weight Sensing System) control unit (N110) (with code (494) USA version)
- TLC control unit (N121) (with code (881) Remote trunk closing (RTC), model 216)

The central gateway control unit routes this signal via the drive train CAN to the following control units:
- Fuel pump control unit (N118) (on gasoline engine)

The central gateway control unit routes this signal via the drive train sensor CAN to the following control units:
- DC/DC converter control unit (N83/1) (model 221.095/195)

The central gateway control unit routes this signal via the central CAN to the following control units:
- COMAND controller unit (A40/3)

The central gateway control unit routes this signal via the chassis CAN to the following control units:
- Multifunction camera (A40/11) (with code (476) Automatic lane recognition, code (513) Speed limit assist, code (608) Automatic high beam control)
- Left front reversible emergency tensioning retractor (A76) (model 221)
- Right front reversible emergency tensioning retractor (A76/1) (model 221)
- Restraint systems control unit (N2/7)
- ESP control unit (N47-5)
- AIRMATIC with ADS control unit (N51) (Model 221 without code (487) Active Body Control (ABC))
- ABC control unit (N51/2) (Model 221 with code (487) Active Body Control (ABC), model 216)
- PTS control unit (N62) (with code (220) PARKTRONIC or code (230) Exclusive parking assist)
- Radar sensor control unit (SGR) (N62/1) (with code (233) DISTRONIC PLUS)
- Steering column tube module (N80)
- TPM [RDK] control unit (N88) (on model 216 with code (475) Tire pressure monitor (Siemens))

The central gateway control unit routes this signal via the front end CAN to the following control units:
- Xenon headlamp control unit (E1n1) (with code (615) Bi-xenon headlamp unit, code (616) Bi-xenon headlamp unit with integrated asymmetrical curve illumination)
- Xenon headlamp control unit (E2n1) (with code (615) Bi-xenon headlamp unit, code (616) Bi-xenon headlamp unit with integrated asymmetrical curve illumination)

If the interior CAN (CAN B), drive train CAN (CAN C), diagnostic CAN (CAN D), chassis CAN (CAN E) and central CAN (CAN F) are in "sleep mode" during signal transmission, the control units are woken up. The involved control units will then prepare themselves for power supply shutoff.
Within t = 5 min, these control units will go into "power-down mode" (decentralized power management).

Shut off consumers function sequence
Following a period of t = 5 min, no-load current management opens the no-load current shutoff relay, provided that no event causing closure of the relay (opening of the vehicle) has occurred in the meantime. The front SAM control unit sends the status of the no-load current shutoff relay via the interior CAN. The central gateway control unit receives this and makes it available to the other control units via the chassis CAN.

Energize consumers function sequence
When the system wakes up, no-load current management closes the no-load current shutoff relay and all functions are made available again. The no-load current shutoff relay will open again following a waiting time of t = 6 h or if the on-board electrical system voltage falls to U < 12.2 V or if the no-load current is too high. If the front SAM control unit receives a wake-up signal, the no-load current management system closes the no-load current shutoff relay. The central gateway control unit signals via the CAN that the wake-up conditions for the control units have been enabled again.

Closing the no-load current shutoff relay causes power to again be supplied via circuit 30g.

The following conditions will trigger the closure of the no-load current shutoff relay:
- Circuit 15R switches on: The waiting time timer is reset. The no-load current shutoff relay remains closed as long as the status of circuit 15R is ON.
- A door is unlocked or opened or circuit 15C is switched on: The waiting time timer is reset.
- The hazard warning system, the standing or parking lights, or the signaling system on special-purpose vehicles is switched on: The waiting time timer will be reset.
- The anti-theft alarm system (ATA [EDW]) is activated (with code (551) Antitheft alarm system (ATA [EDW])): The waiting time timer will be reset.
- The panic alarm is triggered (with code (763) Radio remote control with panic switch): The waiting time timer will be reset.

No-load current diagnosis function sequence
No-load current diagnosis records data to help troubleshoot possible fault profiles.

The no-load current diagnosis function comprises the following subfunctions:
^ Activate no-load current diagnosis function sequence
^ Cancel/end no-load current diagnosis function sequence

Additional function requirements for Activate no-load current diagnosis
^ Terminal 15R OFF

Activate no-load current diagnosis function sequence
Any of the following wake-up events will cause the battery sensor to start no-load current diagnosis via the on-board electrical system LIN:
- Increased no-load current following expiration of tolerance time of t = 75 min
- On-board electrical system voltage values fall below limits and there has been a change in the kilometer reading since the last fault roll entry caused by undervoltage (also before expiration of tolerance time of t = 75 min)

The first wake-up event causes an entry to be made in the no- load current information roll. The no-load current value is then monitored cyclically from that time on. The values will be updated if there are significant changes or if the no-load current diagnosis is canceled.
The following data are stored in nonvolatile memory in the no-load current fault roll:
- No-load current value upon occurrence of wake-up event
- Maximum no-load current during no-load current fault phase
- Minimum no-load current during no-load current fault phase
- Voltage of on-board electrical system battery upon occurrence of wake-up event
- Voltage of on-board electrical system battery at end of no-load current fault phase
- Duration of no-load current fault phase (in minutes)
- Kilometer reading
- Consumer status

As long as no-load current diagnosis is active, each additional battery sensor wake-up event will cause the data record to be updated.

Additional function requirements for Cancel/end no-load current diagnosis
^ Terminal 15R
^ On-board electrical system voltage values fall below limits

Cancel/end no-load current diagnosis function sequence
No-load current diagnosis will be canceled if the on-board electrical system voltage values fall below the defined limits. The battery sensor will discontinue no-load current monitoring in order to minimize electricity consumption. Once this happens, no further entries will be added to the fault roll.

Assisted charging/jump start, function sequence
If the on-board electrical system battery does not provide enough capacity to start the engine, the on-board electrical system battery must be charged or jump starting must be performed.

If with model 221.095/195 the power output of the high-voltage battery (A100g1) is extremely low (P < 8 kW) when the hybrid drive system is started, startability can be reestablished by means of energy transfer from the 12 V on-board electrical system to the high-voltage on-board electrical system. If an external charger is connected and, with the engine hood open, the DC/DC converter control unit measures a voltage of more than U = 12.8 V in the 12 V on-board electrical system, energy with a maximum output of P = 500 W is transferred via the on-board electrical system battery and the DC/DC converter control unit to the high-voltage on-board electrical system and the high-voltage battery is charged (only with circuit 15 ON).

Component Identification:

Only charge the on-board electrical system battery in a well ventilated room.
Only switch on the charger after connecting it to the terminals; switch it off before disconnecting.
Charge the on-board electrical system battery with direct current only; the charging current should be equal to approx. 10 % of the battery's capacity.

Component Identification:

The positive terminal point (1) is not designed for the level of current occurring during jump starting; the cables must therefore be connected directly to the positive terminal when the jump start procedure is performed.