Closed-Circuit Current Test

Example of a Closed-Circuit Current Test:

Closed-Circuit Current Test:

1 Ammeter
2 Battery
3 Body ground lead disconnected
4 Ground point in vehicle

Measuring instrument: Ammeter

Important!

The BMW SERVICE TESTER is not suitable for the closed-circuit current test!

Notes:

When performing the closed-circuit current test avoid interrupting the power circuit in order

- not to clear the defect code memories and adaptation values in the control units,
- not to have any stuck relays drop out,
- not to exceed the measuring range of the ammeter.

Test Procedure:

Step 1:

Switch off all loads which can be switched oft.

Close and, if necessary, central arrest all doors and front/rear lid with the exception of the door or lid which provides access to the vehicle battery:

- Battery under rear seat - leave right rear door open
- Battery in engine compartment - leave front lid open
- Battery in luggage compartment - leave rear lid open.

Step 2:

Connect the leads of the ammeter to the ground lead of the battery and to a ground point on the body.

Attention!

Do not disconnect ground lead from the body at this point!

Step 3

Lock and arrest vehicle via central locking system.

Then wait at least 5 minutes (control units assume closed-circuit current mode).

Attention!

Do not interrupt power circuit during this period of time!

Step 4:

After the waiting time has elapsed, disconnect the ground lead from the body.

Attention!

Do not interrupt power circuit when releasing the ground lead!

Step 5:

Press light contact switch on door or lid.

The ammeter shows the closed-circuit current.


Defect:

A closed-circuit current of more than 50 mA indicates a problem.