10-13-2022, 11:58 AM | #1 |
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PLEASE HELP! TCU or bad battery?
My car has been experiencing battery drain and and will die in about a couple days. My speakers are popping even with car turned off.. my tail lights will randomly turn on also. I also have an SOS warning light on. I am not sure if this is my battery or TCU. I really need my car up and running and don't want to take it into the dealer! I tried to bypass the data lite radio with fiber optic but it didn't work. There is also a cord that is under the steering wheel that is supposed to be flashing red to tell you if the TCU is in good condition.. and it is not red. Please help! Any ideas?
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10-13-2022, 01:30 PM | #2 |
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Unplug any accessories or hard-wired radar detectors. Get the fuse map from under the lid in the trunk. Check EACH of the fuse boxes for blown fuses, the car has a few fuse panels. Also check that the right Amperage fuse is in the correct slots, and no one mixed them up. If the problem is still there maybe remove the fuse for the entertainment system (to shut down the radio circuit) and see if the speaker pops stop.
When you said TCU (trans control unit?) did you mean the DME (main computer)? There are other spots that have "electronic modules" like the FEM, which have non-replaceable fuses inside. Those are harder to diagnose.
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'18 F80 Base 6MT | '19 F82 Exec DCT | '18 F82 Comp Exec DCT | '23 G80cx
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10-13-2022, 01:44 PM | #3 | |
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Quote:
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10-14-2022, 06:51 PM | #4 |
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Do a parasitic draw test. Very easy to do, just takes time to pull one fuse at a time and reading the amperage on voltmeter.
Obviously start from common items that typically cause battery drain issue like comfort access, tcu since u do have sos fault etc. |
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10-15-2022, 01:53 PM | #5 |
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How do I turn comfort access off? I do not have a screen
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