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Home >> Mercedes Benz >> 2007 >> CL600 >> Repair and Diagnosis (Single Page) >> Electrical >> Charging Systems >> Battery, Collision Avoidance, Control Modules/Units, Displays, & Fuse/Relay Assignment -- Basic Knowledge -- Cl600 (216.376) >> Basic Knowledge >> Engine off energy management, function - GF54.10-P-1050LE

Engine off energy management, function - GF54.10-P-1050LE

MODEL 216.3, 221.0 /1 as of model year 2009 /YoM 08 

Function requirements, general 

IMPORTANT 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 (CAN B).

IMPORTANT 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 on-board 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:

Additional function requirements for consumer shutoff 

D Circuit 15 ON or Circuit 15R ON

D On-board electrical system emergency mode not active

IMPORTANT The circuit status of circuit 15 is provided on the interior CAN by the EIS [EZS] control unit (N73).

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:

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 table below.

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

Sequence Consumers whose power supply is reduced or shut off Responsible control unit Maximum current A
1 Heating level 6, PTC heater booster (R22/3) (with engine 629.9, 642.8), passenger side AAC [KLA] control unit (N22/1) 18.5
2 Heating level 5, PTC heater booster (R22/3) (with engine 629.9, 642.8), driver side AAC [KLA] control unit (N22/1) 18.5
3 Heating level 4, PTC heater booster (R22/3) (with engine 629.9, 642.8), passenger side AAC [KLA] control unit (N22/1) 18.5
4 Heating level 3, PTC heater booster (R22/3) (with engine 629.9, 642.8), driver side AAC [KLA] control unit (N22/1) 18.5
5 Heating level 2, PTC heater booster (R22/3) (with engine 629.9, 642.8), passenger side AAC [KLA] control unit (N22/1) 18.5
6 Heating level 1, PTC heater booster (R22/3) (with engine 629.9, 642.8), driver side AAC [KLA] control unit (N22/1) 18.5
7 Rear blower motor (M2/1) (with code (582) Rear air conditioning) P = 50% AAC [KLA] control unit (N22/1) 8
8 Blower motor (A32m1) P = 50% AAC [KLA] control unit (N22/1) 16.0
9 AAC with integrated control additional fan motor (M4/7) P = 50% AAC [KLA] control unit (N22/1) 31.0
10 Trailer hitch socket (13-pin) (X58) (with code (550) Trailer hitch socket) Trailer recognition control unit (N28/1) (with code (550) Trailer hitch) 8
11 Power outlet relay (N10/2kO) and cigar lighter relay (N10/2kR) Rear SAM control unit with fuse and relay module (N10/2) 6
12 Seat ventilation (with code (401) Front comfort seats, incl. seat heating and seat ventilation) Left front seat control unit (N32/1) and right front seat control unit (N32/2) 2.2
13 Seat heater, stage 3 (with code (401) Front comfort seats, incl. seat heating and seat ventilation) Left front seat control unit (N32/1) and right front seat control unit (N32/2) 13.2
14 Heated rear window (R1) Rear SAM control unit with fuse and relay module (N10/2) 30.0
15 Wiper park position heater (R2/10) Front SAM control unit with fuse and relay module (N10/1) 15
16 Seat heater level 2 (with code (873) Seat heater for left and right front seats) Left front seat control unit (N32/1) and right front seat control unit (N32/2) 13.2
17 Seat heater stage 1 (with code (873) Seat heater for left and right front seats) Left front seat control unit (N32/1) and right front seat control unit (N32/2) 3.3
18 Steering wheel heater electronics (A74) (with code (443) steering wheel heater) Steering column tube module (N80) 8
19 Heated windshield (R22/2) Front SAM control unit with fuse and relay module (N10/1) 50 to 74
20 Mirror heater (M21/1r1) and mirror heater (M21/2r1) On model 221:
Left front door control unit (N69/1) and right front door control unit (N69/2)
On model 216:
Left door control unit (N69/1) and right door control unit (N69/2)		 3.5
21 Residual engine heat utilization function AAC [KLA] control unit (N22/1)  
Air conditioning 8
Rear air conditioning 6
22 Interior lighting Overhead control panel control unit (N70) 1
23 Roof sign, printer and card reader (accessories) Special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) (with code (965) Electrical preinstallation for rental vehicle) 5
24 Stationary heater (with code (228) Stationary heater) STH heater unit (A6) (model 216) STH or HB heater unit (A6) (model 221) 10
25 Audio components COMAND controller unit (A40/3) 2

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 

IMPORTANT The EZS 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.

To this end, 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:

No-load current management comprises the following subfunctions:

No-load current shutoff function sequence 

The no-load current shutoff function comprises the following subfunctions:

Request consumer shutoff function sequence 

During the transition from circuit 15R to circuit 15C, the vehicle changes to 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.

IMPORTANT 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:

(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)

221 with code (550) Trailer hitch)

The central gateway control unit forward this signal via the drive train (CAN C) to the following control unit:

The central gateway control unit forwards this signal via the drive train sensor CAN (CAN I) to the following control units:

The central gateway control unit forwards this signal via the central CAN (CAN F) to the following control units:

The central gateway control unit routes this signal via the chassis CAN to the following control units:

The central gateway control unit forwards this signal via the front end CAN (CAN G) to the following control units:

If the interior CAN, drive train CAN, diagnostic CAN (CAN D), chassis CAN and central CAN 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 

The central gateway control unit signals via the CAN that the wake-

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.

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.

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:

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:

Additional function requirements for Activate no-load current diagnosis 

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:

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:

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 

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.

No-load current reference value/residual-load current evaluation (production only, at end of line), additional function requirements 

No-load current reference value/residual-load current evaluation (production only, at end of line), function sequence 

No-load current reference value measurement function sequence 

The measurement of the no-load current reference value is started using the diagnostic tester at circuit 15R or higher. The message "Measure no-load current!" appears in the multifunction display (A1p13) of the instrument cluster (A1). The diagnostic tester must then be removed and the vehicle locked so that the vehicle's no-load

After the vehicle has gone through production testing and possible runs on the test track, the no-load current has to be measured and an assessment made of the residual charging current of the onboard electrical system battery.

The no-load current-reference value/residual load current evaluation is comprised of the following subfunctions:

current will quickly drop. The battery sensor will then sense and save the maximum no-load current level to occur following the locking of the vehicle.

After the vehicle is woken up, the battery sensor sends the measured no-load current value via the on-board electrical system LIN to the front SAM control unit, which then stores it as the no-load current reference value in nonvolatile memory.

The no-load current reference value can be read out using the diagnostic tester.

IMPORTANT If the measured no-load current is within a defined tolerance range, the message in the multifunction display will disappear.

IMPORTANT If the no-load current reference value is too high, a fault message will be shown in the multifunction display of the instrument cluster and measurement will begin again.

Residual charging current assessment function sequence 

During production, charge is removed from the battery in the course of various function tests. The charge level of the on-board electrical system battery must therefore be assessed at the end of assembly. The charge level (ratio of current charge to the maximum storable charge in the on-board electrical system battery) serves as the measure for a sufficiently charged on-board electrical system battery. This value must be above 80%.

If the charge level is below 80%, a fault message will be shown in the multifunction display of the instrument cluster. Measurement of the residual charging current is only done following successful measurement of the no-load current reference value. As a rule, the two values are released together.

Function sequence of remote charging/jump start 

If the on-board electrical system battery does not have enough capacity to start the engine, the on-board electrical system battery must be charged or a jump start carried out.

IMPORTANT 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).

REFER TO SYSTEM WIRING DIAGRAMS Electrical function schematic for consumer shutoff Model 216 PE54.10-P-2066-97CAA
Model 221 PE54.10-P-2066-97SAA
  Component description for instrument cluster A1
Model 216.3, model 221 (except 221.095/195)		 GF54.30-P-6000LE
Model 221.095/195 GF54.30-P-6000LEH
Component description for ME-SFI [ME] control unit With engine 275 GF07.61-P-6000MOS
On model 221 with engine 276 GF07.61-P-6000MMB
  Component description for front SAM control unit with fuse and relay module N10/1 GF54.21-P-6070LE 
  EZS control unit, component description N73 GF80.57-P-6003LE
  Component description for central gateway control unit N93 GF54.21-P-4170LE 
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