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My 2003 E55 has suddenly developed a battery drain. The batteries are under a year old and worked fine. Now the rear battery will drain overnight. Alternator works as it should.
I read the voltage across each fuse and used the conversion chart for mA current draw. I found what I think is fuse 85 (second 5A orange fuse from the right), in the trunk near the battery, pulling 6.1mA that corresponds to about 560mA current draw. The chart I have says that fuse 85 powers Telephone interface, Universal portable CTEL interface, Hands-free system control unit and Voice control system control unit.
Armed with that information I messed around for a long time trying to open the plastic cover over the microphone control module, Communications platform control module, telephone antenna splitter and linear compensator. After what seemed like forever I was able to see how the tabs worked and I got the cover off. I found that removing the power cable to the back side of the Communication platform control module (CP) the draw went to zero. Removing other connectors connected to the CP module did not affect the readings.
I know I have a bad siren that needs to be replaced, but I ran out of time to get that done. What fuse does a defective alarm siren usually cause a drain on? I will replace it anyway when I get a chance. Want to be sure the drain on fuse 85 is not related to the alarm siren.
Is the Communication platform control module a module that I can just swap in, or does it need to be coded? If so I so have star but I can not find any information on this module at all as how it may be done?
I would really appreciate any information that anyone has with this. Especially if you have had an issue with a draw at fuse 85 yourself or had to replace the Communication platform control module (CP).
Leave the CP module unplugged. Code the system out using STAR. That is for the old analog cell phone which is no longer compatible with the more recent digital systems.
Unplug and remove the alarm module. Replace if possible. You will get an error message in Star but it should have no effect on the car. It takes maybe 30 minutes.
Thanks you for the information. I have a new alarm siren so I will install it and the alarm issue should be fixed.
Do you know happen to know the path of how to get to the CP Module in STAR to code it out?
Instructions on how to code it out with star have been posted several times. I coded mine out using the other instructions and I posted about it. I'll see if I can find the information and repost it here again.
Edit: going from memory I seem to remember it is under Control Modules/Chassis/Instruments and Telecommunications, set the cell phone/MB assist to "not present" and save.
Last edited by bbirdwell; Nov 7, 2021 at 05:33 PM.
I think I found it. You had responded to someone having an issue with a message coming on the dash. Does this look correct?
In Star Diagnosis: Control Units –> Body –> CGW (Central Gateway) –> Control Unit Adaptations –> Read Coding and Change if Necessary –> Telecommunications –> Telematics Service “Tele Aid” in combination with MOST technology.
You will need to change TeleAid coding from PRESENT to NOT PRESENT and the error on the instrument cluster will no longer appear.
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