AR54.10-P-1030-04C Determining Circuit with Increased Quiescent Current

Determining Circuit with Increased Quiescent Current

Commercially Available Tools:

1 Check trunk illumination, if necessary replace damaged part.

NOTE: Unclip trunk lamp, pull off insulated terminal and measure current with multimeter (amps range). After checking observe after running time of approx. 10 min. again.
If total current consumption is <= 0.05 A or <= 0.09 A (vehicles with alarm system code 551), end of test:

If total quiescent current is not reached:
2 Open fuse boxes F1, F4 and light module cover (N7-1).
3 On vehicles with ATA, lock engine hood lock with screwdriver.
4 Lock vehicle.
5 Open cover on overvoltage protection device.

NOTE: Observe information update (Al)!
First check circuits for components listed in the information update.

6 Remove fuse for affected component.

NOTE: Remove fuse for ATA only with vehicle unlocked (alarm signal).

7 Connect test cable (6) and test adapter (13) to a second multimeter (12) (amps mode).
8 Pull out first fuse and connect second multimeter in its place. Read off quiescent current after waiting 5 seconds.

Quiescent current <= 0.02A (20 mA):
The fused circuit is okay.

9 Reinstall fuse, wait 5 seconds.
Then check quiescent current for all fuses according to test step 8.

NOTE: After reinstalling the fuses or the test adapter, the connected components may have an increased quiescent current momentarily; the quiescent current for the radio may be as high as 0.240 A (240 mA).

The increased quiescent current consumption is eliminated by switching the radio on and off again.

Quiescent current > 0.02 A (20 mA):
The fused circuit is defective:
Determine fused components for which quiescent current is too high.

If nominal value for total quiescent current is still not reached:
Determine unfused components for which quiescent current is too high.