Measurement of Closed-Circuit Current - II

Measurement Of Closed-Circuit Current

Tools

Item 1:

Closed-circuit current should be measured using an analog ammeter or a digital multimeter with a long integration time (to filter out voltage peaks).

Preparations on the vehicle

NOTE: Before measuring the closed-circuit current, determine the vehicle equipment (M-numbers) and establish the expected closed-circuit current with the aid of the attached table.

1. Open the front luggage compartment.
2. Using a suitable tool - e.g., upper part of lock with a suitable handle - close lower part of luggage compartment lock while keeping the luggage compartment lid open.
3. Remove the ignition key and lock the vehicle with the key (alarm system is activated).

Connect Measuring Instrument
1. Set the measuring instrument to the highest possible current-measuring range.
2. With two alligator clips, connect the measuring instrument to the battery ground and to the unoccupied second body ground which is always available for RHD or LHD.
3. Remove ground strap from the body and secure against contact with the body. The entire vehicle current now flows through the ammeter.

Measurement
- Select a measuring range which ensures that the pointer of the instrument is in the upper third of the scale, as far as possible. Switch over measuring range without interruption. Read off the measuring values after the waiting period specified in the table.
- Do not switch on any electrical loads (opening the central locking system) during measurement.

NOTE:
- If the value of the closed-circuit current is higher than the value determined in the table, the cause must be established systematically.
- The recommended troubleshooting procedure: With the measuring device connected, pull off the fuses of terminal 30 and the relays successively. Observe the display values of the measuring instrument when removing in order to recognize a reduction in current.
- After troubleshooting, screw the ground strap back onto the body in the proper manner.
- The measured values could vary by approx. 20%.
- The values listed in the table depend on the condition of the battery, the room temperature, and the engine temperature.

Reading off the measuring range:










- Read off the measuring range only after 61 minutes have passed since the vehicle was locked.