DON'T SPRAY driver's side engine bay | "Increased battery discharge while stopped"

TouringM3 · 11-03-2021, 10:08 PM

Hey Pals –

Ever since putting the M3 wagon together i've gotten a consistent "Increased battery discharge while stopped" error message when the car is parked for longer than 2 days.

Figured it was all my fault for playing legos with two European cars, but, it's far more simple.

There is a small junction box (Integrated Supply Module) on the driver's side fire wall which contains a few crucial relays, and also connects the main chassis power to the DME.

Well, go figure, this is NOT a waterproof component. The combination of having sprayed coolant on it while filling / bleeding my system, and then doing a perhaps slightly overzealous engine bay cleaning definitely put the slow death to this module.

So, pro tip from the village idiot here, don't spray it down, don't get it wet, maybe don't even clean it. In fact, don't even think about water looking at it.

Photos and diagram attached.

TopJimmy · 11-03-2021, 10:30 PM

A while back on my F80 the DME and ISM both got fried from "liquid intrusion" on one connector. BMW considered it "external influence" and warranty wouldn't cover it.

+100 for NOT washing your S55 engine.

11-03-2021, 10:08 PM	#1
TouringM3 Lieutenant 620 Rep 498 Posts Drives: '18 F80 6MT / '16 F31 Join Date: May 2020 Location: Bend, OR iTrader: (0) Garage List 2018 F81 M3 Touring [10.00] 2016 F30 328xi Comp ... [0.00]	DON'T SPRAY driver's side engine bay \| "Increased battery discharge while stopped" Hey Pals – Ever since putting the M3 wagon together i've gotten a consistent "Increased battery discharge while stopped" error message when the car is parked for longer than 2 days. Figured it was all my fault for playing legos with two European cars, but, it's far more simple. There is a small junction box (Integrated Supply Module) on the driver's side fire wall which contains a few crucial relays, and also connects the main chassis power to the DME. Well, go figure, this is NOT a waterproof component. The combination of having sprayed coolant on it while filling / bleeding my system, and then doing a perhaps slightly overzealous engine bay cleaning definitely put the slow death to this module. So, pro tip from the village idiot here, don't spray it down, don't get it wet, maybe don't even clean it. In fact, don't even think about water looking at it. Photos and diagram attached. Attached Images __________________ 2018 F81 M3 Touring Project \| Bend, Oregon, USA Instagram: @TouringM3
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11-03-2021, 10:30 PM	#2
TopJimmy Major General 5462 Rep 5,154 Posts Drives: 2023 M3 Comp xDrive Join Date: Jul 2019 Location: Chester County, PA iTrader: (5)	A while back on my F80 the DME and ISM both got fried from "liquid intrusion" on one connector. BMW considered it "external influence" and warranty wouldn't cover it. +100 for NOT washing your S55 engine. __________________ '18 F80 Base 6MT \| '19 F82 Exec DCT \| '18 F82 Comp Exec DCT \| '23 G80cx
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