Closed Circuit Current Monitoring Procedure
Closed Circuit Current Monitoring Procedure:
The following instructions can be supplemented with the HI document in DIS under Power supply Diagnostic Test Plan, entitled "Procedure in event of dosed circuit current faults". There are examples of closed-circuit current violations with additional diagnostic hints.
1. With the DISplus/GT1, interrogate all control modules with a short test. Correct all faults before proceding with closed circuit diagnosis. This includes reviewing diagnostic queries for the Power Module to analyze reasons for battery disconnects, battery SOC, battery history and basic charging operation.
2. Disconnect battery charger from the vehicle (remove clamps).
3. Open the trunk lid and secure the latch mechanism (as if the trunk lid was closed).
4. Open hood and lift up on the hood pin switch (service position).
5. To prepare for fuse access, open the glove box door and disable the glovebox light. This will avoid awakening the Power Module later.
6. Hook up current monitoring tools following this progression:
If using the DiSplus:
- 50 amp inductive clamp around the B- cable from the battery to chassis ground. Access the BMW Test system "Multimeter screen", and select the "Current 50A" setting and "MIN/MAX".
Preferred - MoDIC/GT1 (when function is available on GT1)
- 50 amp inductive clamp around the B- cable from the battery to chassis ground.
- MFK1 connected to Special Tools # 61 2 300 and # 61 2 310. Follow MoDIC setup instructions per SIB # 61 08 00 (do not plug into MoDIC yet, just have connections ready), do not disconnect the chassis ground at this time. This tool can only handle a current of 10 amps or less and will fail until the vehicle current is safely below this value.
7. Shut off ignition "KL 0", remove the remote key from vehicle. Open both front doors and secure rotatory latch (as if the doors were closed), Use a suitable tool and not your finger! Be careful not to catch your fingers in the latch, the vehicle may be equipped with Soft Close Automatic (SCA). Activate the remote locking "twice" (to disable the FIS sensor) and begin to watch for Bus power down.
8. After the CAS LED goes out (approx. 2 minutes), the current draw should not be > 800 mA. The BZM lights will remain on.
9. After approximately 16 minutes, the CAS LED will illuminate. The current draw will spike to approximately 8 - 9 A for 30 seconds. Then the CAS and BZM lights go out and the current draw will be approximately 200 mA for 60 - 70 minutes. Unplug the 50 amp clamp lead from the MoDIC and plug in the MFk1 lead, it is now safe to remove the chassis ground and The draw trace will begin if The MoDIC/GT1 is used.
At the 60 - 70 minute point (sleep mode), if the closed-circuit current draw is > 30 mA, normal procedures of pulling fuses and disconnecting components will be necessary (as outlined below). Remember to divide and conquer the circuits with the help of the ETM.
If the closed-circuit current draw remains higher than 30 mA after 60 minutes or never drops down to less than 30 mA proceed as follows (the MoDICIGT1- when function is available on GT1, must be used at this point to establish a draw trace):
10. Remove Fuse 5 from the front fuse box behind the glove compartment (Fuse 5 also powers the BZM, the seat switch lights will go out). Wait 2 minutes (allows CAS to reset) and recheck draw.
If draw drops down to below 30 ma reinstall Fuse 5 and disconnect 1 MOST bus consumer at a time (Control Display last - it is the gateway) and install optic jumper (made from parts, available in EPG) wait 2 minutes between each disconnection (allows CAS to reset).
11. If draw is still present after Fuse 5 removal, remove Fuse 15 to ZGM from front fuse box, this isolates the Byteflight Bus from PT-CAN Bus.
If draw drops down, then disconnect SIM module behind glove box and reinstall Fuse 15. If draw drops after SIM removal then draw is from Byteflight and isolate which Byteflight module is causing draw. If draw does not drop after SIM removal, the draw is coming from PT-CAN bus. Disconnect each PT-CAN Bus module until draw is gone.
12. If removing Fuse 5 and or Fuse 15 do not drop draw below 30 mA, then draw is from K-CAN S and or K-CAN P modules. Disconnect one CAN consumer at a time until draw is gone.
NOTE: Please refer to Bus Chart.
Bus Chart:
Closed Circuit Current Monitoring Flow Chart
Sleep Mode with PT-CAN Bus Consumer (example)
When the closed-circuit current draw remains higher than 30 mA after 60 minutes or never drops down < 30 mA, the MoDIC/GT1 (when function is available on GT1) used at this point establishes a draw trace.
In this example, a consumer stays awake after the 60 - 70 minutes. From the peaks you can observe that the closed-circuit current draw is not normal.
By removing Fuse #15 to ZGM (in front fuse box), the Byteflight and PT-CAN Bus circuits are isolated and the closed-circuit current draw decreases to a normal value.
After disconnecting SIM module and reinstalling fuse #15, the draw still exists indicating that it is from PT-CAN bus.
By disconnecting each PT-CAN Bus module (one at a time), the draw decreased after the Electro-mechanical Parking Brake Control Module (EMF) was unplugged. This component was staying awake and in addition, awoke the entire Bus network.