In general, closed circuit current consistently over 50 mA must be investigated. Depending on the vehicle's equipment, closed-circuit current by vehicle model is approximately as follows:
E31 50 milliamps
E32 50 milliamps
E34 40 milliamps
E36 30 milliamps
E38 50 milliamps
E39 40 milliamps
E46 40 milliamps
E53 40 milliamps
Z3 30 milliamps
Z8 50 milliamps
1. Check battery voltage is a minimum of 12 volts. If necessary, recharge the battery.
2. Switch off all other electrical consumers, paying particular attention to the telephone and any retrofitted special equipment.
3. If the battery is installed in the trunk, open the trunk and turn the lock to the locked position using a screwdriver or similar (simulates the trunk lid being closed). The hood must be closed.
If the battery is installed in the engine compartment, open the hood and pull the front lid contact switch fully up and lock in this position (workshop position, simulates the front lid being closed). The trunk must be closed.
4. With the exception of the trunk / hood above, all other doors / lids must be closed.
5. In order to simulate normal closed circuit conditions:
-- Open the driver's door and close it again (simulates somebody getting in).
-- Switch the ignition "on" for at least 5 seconds and then switch it "off" again (simulates driving).
-- Open and close the driver's door again (simulates somebody getting out).
-- Lock the car, arming DWA if this is installed.
6. Wait 16 minutes for consumer cut-off. (On automatic transmission vehicles, consumer cut off is visually indicated when the amber shifter LED goes out). Closed circuit current can now be measured.
7. Using the closed-circuit current measurement adapter 61 2 300:
-- Connect the red clamp (marked "BATT +") (1) to the battery positive terminal.
-- Connect the black clamp (marked "CHASSIS") (2) to a the ground support point on the body (or other suitable ground).
-- The green LED (3) illuminates to indicate correct installation.
-- Connect the black clamp (marked "BATT -") (1) to the negative battery terminal.
-- The green LED (2) goes out.
-- Note: Any electrical overloading will be indicated by the red LED illuminating. In such cases, the adapter connection should be checked and corrected as necessary
-- Set the multimeter to the10 amps measuring range.
-- Connect the multimeter to the adapter.
-- Disconnect the battery ground (1) from the body.
-- Measure the closed-circuit current on the multimeter.
-- After measuring the closed-circuit current, reconnect the battery ground cable (1) before removing the clamps. Then switch the ignition "on" for at least 5 seconds and then "off" again to prevent faults due to non-initialized control units.
11. Interpretation of Measurements taken with a Multimeter
BMW recommends the use of Fluke Models 83 and 88. Most multimeters have a "powersave" feature which shuts down the meter after a certain period of time. With the Fluke Models 83 and 88, this "powersave" feature is automatically disabled when using
"MIN MAX" or "AVG". Operating characteristics of other makes and models may vary -consult the operating instructions for details.
With the Fluke meter set in regular mode, and if systems are functioning normally, the closed circuit current will be seen to maintain a reasonably constant level, with momentary excursions to higher currents as system modules perform occasional update duties. These occasional fluctuations should be ignored. With the Fluke meter set on "MIN MAX", these occasional fluctuations (sometimes over 100 mA), will be recorded. As a result, care should be taken when interpreting the results when the meter is used with this setting. In general, the use of "MIN MAX" is not recommended for this reason. With the Fluke meter set on "AVG" (Average), the momentary fluctuations are averaged out.
This is the recommended setting to use...
If the average closed circuit current measured after an overnight test is within the value for the vehicle model (step 6), the system is performing satisfactorily.
If the average closed circuit current measured after an overnight test results in a higher than expected current, further investigation is required. In such cases, the use of the MoDiC is recommended (see step 12)