Testing quiescent current consumption - ra540a1401030x(1030)

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

A. Testing total quiescent current consumption Model 140

Preliminary work:

Testing battery charge state.

All assemblies and components in vehicle operating properly.

Operation no. of operation texts and work units or standard texts and flat rates:

Testing total quiescent current consumption

Fig 1: Testing Quiescent Current Consumption

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

PREPARING FOR TEST

If engine warm (coolant temperature >100 °C)	wait 12 minutes because of after-run cooling of heating water circulation pump. NOTE: After switching off ignition, the heating water circulation pump switches on for 10 - 12 minutes if coolant temperature is >100 °C and cools down the engine.
Left and right front door, side window	lower.
All electrical components	switch off, e. g.: remove ignition key switch off stationary heater switch off car phone switch off radio fold up vanity mirror switch off reading lamps turn exterior lamp switch to position "0" close door, interior lighting must go out automatically after a few seconds. NOTE: Take care not to exceed maximum current rating for multimeter; when the central locking system pump starts up a current of approx. 20 A flows.

PREPARING TEST WITH QUIESCENT CURRENT MAINTENANCE UNIT

Quiescent current maintenance unit (7)	connect as follows: Ground cable ( - ) to battery ground (W10). Positive cable (+) to positive pole of battery.
Quiescent current maintenance unit (7)	switch on.
Ground cable (1) at battery	disconnect.
Multimeter (2)	connect as follows; use "electrical connection set" (201 589 00 99 00) for this purpose. Positive cable (+) to ground terminal on battery (W10). Negative cable ( - ) to negative pole of battery (3).
Multimeter (2)	switch on (Mode: Amps).
Quiescent current maintenance unit (7)	switch off and disconnect.
Test cable (6)	run to the right out of the trunk.
Trunk lid	close.

COMMERCIALLY AVAILABLE TESTER

Multimeter	e. g. Sun DMM-5
	e. g. Fluke, 88
Quiescent current retention unit	e. g. Hans Zeheter CMP 12.2

PREPARING TEST WITHOUT QUIESCENT CURRENT MAINTENANCE UNIT

Nut on battery ground pole terminal	loosen.
	Do not disconnect ground pole terminal! Do not interrupt circuit when pulling negative pole terminal off to prevent erasing any DTC's present. Completely disconnect the negative pole terminal only after the multimeter test cable is tightly clamped to the negative pole.
	NOTE: On vehicles with auto pilot system the quiescent current increases to approx. 600 mA for approx. 30 minutes when the circuit has been interrupted!
Multimeter (2)	switch on (Mode: Amps).
Multimeter (2)	connect as follows; use "electrical connection set" (201 589 00 99 00) for this purpose. Positive cable (+) to battery ground (W10). Negative cable ( - ) to negative pole of battery (3).
Ground cable (1) at negative pole of battery (3)	pull off carefully.
	Do not interrupt circuit to avoid erasing any faults stored.
Multimeter (2) with test cable (6)	run to the right out of the trunk.
Trunk lid	close.

COMMERCIALLY AVAILABLE TESTER

Multimeter

e. g. Sun DMM-5
e. g. Fluke, 88

TEST

Test step	Scope of test	Test instrument/Test connection	Action/Prerequisite	Nominal value	Possible cause/Remedy
1	Quiescent current	W10 G1	Lock vehicle. NOTE: Lock vehicle with infrared central locking using remote control. Wait approx. 4 minutes (after-running time for electronic components). Auto pilot system (APS) If the circuit has been interrupted the quiescent current increases by approx. 600 mA, a waiting time of approx. 30 minutes must then be maintained.	Quiescent current ≤ 0.05 A (50 mA) or ≤ 0.085A (85 mA) on vehicles with immobilizer	Readout ≤ 0.05 A, or ≤ 0.085 A (on vehicles with immobilizer) Perform test step 2. Readout > 0.05 A, or > 0.085A (on vehicles with immobilizer) Perform test step 3.
2	Quiescent Current	W10 G1	Unlock vehicle. NOTE: Unlock vehicle with infrared central locking using remote control. Wait approx. 4 minutes (after-running time for electronic components). Auto pilot system (APS) If the circuit has been interrupted the quiescent current increases by approx. 600 mA, a waiting time of approx. 30 minutes must then be maintained.	Quiescent current ≤ 0.05A (50 mA) or ≤ 0.085A (85 mA) on vehicles with immobilizer	Readout ≤ 0.05 A, or ≤ 0.085 A (on vehicles with immobilizer) End of test. Readout >0.05 A, or > 0.085 A (on vehicles with immobilizer) Perform test step 4.
3	Quiescent current	W10 G1	Unlock vehicle. NOTE: Unlock vehicle with infrared central locking using remote control. Wait approx. 4 minutes (after-running time for electronic components). Auto pilot system (APS) If the circuit has been interrupted the quiescent current increases by approx.600 mA, a waiting time of approx. 30 minutes must then be maintained.	Quiescent current ≤ 0.05 A (50 mA) or ≤ 0.085 A (85 mA) on vehicles with immobilizer	Readout ≤ 0.05 A, or ≤ 0.085 A (on vehicles with immobilizer) Note reading. Then continue according to B. Readout >0.05 A, or >0.085 A (on vehicles with electronic immobilizer) Perform test step 4.
4	Quiescent current	W10 G1	Open trunk lid. Actuate microswitch on trunk lock (5). Wait approx. 4 minutes (after-running time for electronic components). Auto pilot system (APS) If the circuit has been interrupted the quiescent current increases by approx.600 mA, a waiting time of approx. 30 minutes must then be maintained.	Quiescent current ≥ 0.05 A (50 mA) or ≤ 0.085 A (85 mA) on vehicles with immobilizer	Readout ≤ 0.05 A, or ≤ 0.085 A (on vehicles with immobilizer) Adjust switch on trunk lock or replace (trunk illuminate). Perform test step 1 again as check. Readout > 0.05 A, or >0.085 A (on vehicles with immobilizer) Note reading. Then continue according to B.