Determining circuit with increased quiescent current consumption - AR54.10-P-1030-04CS

Number	Designation
WH58.30-Z-1001-09A	Multimeter

1. Open fuse and relay box F1 and remove cover.
2. On right engine hood switch (ATA) (S62) keep switch pressed down with insulating tape or lock right engine hood lock with screwdriver.
3. Switch on interior motion sensor if fitted.
4. Lock vehicle

1. 5.1 Open cover on base module (N16/1) in module box (F23).

   Vehicles with module box

2. 5.2 Open cover on fuse box (F20) in trunk.

   Vehicles without module box

   To prevent incorrect measurements, the switch on the trunk lock must be operated with the trunk lid open or if no switch is fitted, as of approx. 1/95 the left and right trunk illumination bulbs must be removed.

   Observe current information (A1). First check the circuits of the components which are listed in the Current Information.

3. Remove fuse of the particular component.

   Only remove the ATA fuse when the vehicle is unlocked (alarm signal).

4. 7.1 Read off quiescent current on the Multimeter connected to the battery and compare with value noted.

   Vehicles up to approx. 08/95

5. 7.2 Connect measuring cable (6) and test adapter (13) to a second multimeter (12) (measuring range in amperes).

   Vehicles as of approx. 09.95

6. 8.1 First remove fuse and connect a second multimeter for this and read off the quiescent current after 5 seconds.

   Vehicles as of approx. 09/95

   If the total quiescent current drops  ≤0.02A (20 mA)  :

   The unfused circuit is in order.

7. Install fuse again and wait for 5 seconds.

Then check quiescent current at all the fuses as per test steps  3 to  7.

After installing the fuse or test adapter, there may briefly be a higher quiescent current at the connected components, with the radio of 0.240 A (240mA).

The higher quiescent current is eliminated by switching the radio on and off.

On vehicles with Auto Pilot System (APS) a higher quiescent current of approx. 800mA occurs after installing the APS computer fusing for the period of the computer run-up (approx. 30 min).

If the total quiescent current drops >0.02A (20 mA)  :

Read off again 4 minutes later.

The fused circuit is defective: ↓

Determine fused components with a higher quiescent current.

Specified value of total quiescent current  is not  reached again: ↓

Determine unfused components with a higher quiescent current.

If the total quiescent current rises >0.02A (20 mA)  :

Determine the cause of the reverse current via a different current path.

Carry out test steps  7.2 to  7.

Vehicles up to approx. 08/95