Check quiescent current consumption - AR54.10-P-1030T

MODEL 211.0/2 

Fig 1: Checking Quiescent Current Consumption

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Shown on model 211.0 

	Removing
	Risk of explosion  caused by oxyhydrogen gas. Risk of poisoning and caustic burns caused  by swallowing battery acid. Risk of injury  caused by burns to skin and eyes from battery acid or when handling damaged lead-acid batteries	No fire, sparks, open flames or smoking. Wear acid-resistant gloves, clothing and glasses. Only pour battery acid into suitable and appropriately marked containers.	AS54.10-Z-0001-01A
	Notes on battery	All models	AH54.10-P-0001-01A
1	Remove trunk floor covering from trunk.
2.1	Remove spare tire cover or spare tire well trim panel from trunk	Model 211.0, depending on equipment
2.2	Remove cover above battery	Model 211.2
3	Prepare vehicle for testing	Prerequisites: Vehicles without  Keyless Go: Ignition switched off, ignition key removed. Vehicle with  Keyless Go: Engine switched off, transmitter key located outside of the vehicle and outside of transmission range.
4.1	Disconnect trailer recognition unit	With code 550 Trailer hitch If the trailer recognition unit was connected, this would result in an erroneous measurement due to the internal resistance of the connected multimeter resulting in the quiescent current being 100 mA too high.*
	Measure
5	Set multimeter to highest possible current measurement range	For protection of multimeter! When central locking is actuated, currents of approx. 20 A flow. Multimeter
6	Connect multimeter between ground lead (1) and negative pole of electrical system battery without interruption	Do not interrupt current flow. To install the multimeter, first jumper negative pole of battery, battery control unit (N82).
7	Read out and erase fault memory
	Connect STAR DIAGNOSIS and read out fault memory		AD00.00-P-2000-04A
		STAR DIAGNOSIS diagnosis system
8	Mark vehicle so that it is easily visible	This is to ensure that the measuring results are not affected by unintentionally opening the doors or working on the vehicle.
9	Close all doors and engine hood
10	Actuate closing wedge on trunk lid lock with trunk lid open	Contact switch to "OFF" position, trunk light goes off.
11	Lock vehicle from outside	Wait a maximum of 6 minutes after locking vehicle.
	Notes on no-load current consumption		AH54.10-P-0003-01T
12	Measure no-load current	An average value of 60 mA should not be exceeded (standard value < 40 mA). Cause of fault 1: If the readings are between 1.2 and 2.5 A, a control unit is usually responsible for keeping the "Bus" awake. Cause of fault 2: In the event of readings between 80 and 180 mA, a control unit usually does not switch off, thereby resulting in an increased quiescent current consumption.
13.1	Separate the control units from the rear SAM control unit with fuse and relay module (N10/2) one after another. After each measurement, reinsert individual fuse and continue with next	In the event of cause of fault 1: Wait 6 minutes in each case, repeat measurement until "bus" goes to sleep. When the fuse for the component causing the problem is removed, the no-load current decreases immediately.
13.2	Remove fuses singly one after another and localize defective control unit	In the event of cause of fault 2
14	Disconnect control units from the CAN voltage distributers	As an alternative to the fuses, it is also possible to disconnect the control units from the bus. see ↓	AR54.10-P-1030-08T
		Wiring diagram for interior CAN bus (X30/4)	PE00.19-P-2300DA
		Wiring diagram for interior CAN bus (X30/7)	PE00.19-P-2300DB
		Wiring diagram for interior CAN bus (X30/6)	PE00.19-P-2300DC
15	Remove multimeter without interruption, connect ground lead (1) to ground point on battery control unit (N82)		*BA54.10-P-1004-01C
	Install
16	Install in the reverse order
17	Read out and erase fault memory
	Connect STAR DIAGNOSIS and read out fault memory		AD00.00-P-2000-04A
		STAR DIAGNOSIS diagnosis system

BATTERY

Number	Designation			Model 211
BA54.10-P-1004-01C	Nut, ground lead to battery control unit	M8	Nm	12