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YOUR RESEARCHParasitic draw on fuse C3
Reported or suspected cause
fuse d8, not d7, i.e
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Reported cause · Original poster
After checking all the spoiler wiring, relays, ground....I realize I counted wrong and the problem is fuse D8, not D7, i.e.
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Performed · outcome unconfirmed · Original poster
Checked the fusebox for a parasitic draw problem and got too much voltage drop across fuse C3 in a 2002 model year coupe, which is "
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Suggestion
(position 1) 141.951.253.B next to the ECU is in line w/ fuse C1, but would think you'd wanna make the measurements I mention above before you start replacing relays.
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Suggestion · Original poster
So from what you're telling me if use a screwdriver to latch the latch with the lid up the light should go out?
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Suggestion
(position 1) 141.951.253.B next to the ECU is in line w/ fuse C1, but would think you'd wanna make the measurements I mention above before you start replacing relays.
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Checked the fusebox for a parasitic draw problem and got too much voltage drop across fuse C3 in a 2002 model year coupe, which is "
CU ALARM-CL, POWER WINOOW, SUN ROOF, CU POWER TOP, INSIDE LIGHT" Sunroof and windows weren't doing anything and the interior lights were not on. Is there a common fault that causes a parasitic draw on this circuit?
I need to correct myself, after you lock the car the C3 circuit stops drawing, but then C1 starts to draw, which is the MFI DI (DME main) relay. Anybody know if this relay normally draws and eventually sleeps? Usually if a relay is drawing I wouldn't expect it not to draw when unlocked and draw when locked, would think it would do it all the time.
Well it may be of no use, but the DME/Alarm/Immobilizer systems remain active for approximately five days listening for the remote. After that the entire system goes to sleep, and the car must be unlocked with the key.
Didn�t know this but glad to hear it since I was having to unlock manually since I�ve only been able to go for a drive once a week for the last month and a half!
Does that list definitely include the DME? If so, that explains why it starts to draw once you lock the car, but man that DME draws a lot. It's no wonder it killed my battery when I went out to the car after 6 days and got something from inside but did not drive, restarting the clock.
You need to get a battery tender. There are plenty of good ones available at almost any auto parts store. And they are not that expensive. Get one that is a tender/charger because it is better for the battery. Just plug into the cigarette lighter and all will be well.
Well, no, after 6 I went out and opened it with the key and restarted the 5 day count down but didn't drive it. As much as the DME draws (1.5mv voltage drop at the fse) once locked, if it is supposed to draw once locked that would be enough no?
How old is your battery? Remember, the immobilizer and DME communicate with each other in the 5 day period of time...always listening for the remote and for the immobilizer to say to the DME, yes, this is the correct remote and the correct key in the ignition.
Battery is fine and healthy. I changed it probably 7 months ago. Charges fine, holds a charge fine, passes a load test. If these things draw about 450mA until the 5 day cutoff though, it doesn't surprise me that it killed it. Hard for me to believe it burns that much on a key check, but I guess this plus an electronic trunk latch switch is how the Germans get back at us for WW2.
Not trying to muddy up the waters here, but what is the measured draw across C1, measured in amperage? From what i've read 50ma is about the max draw you'd wanna see on most Porsche cars, anything more and you have a problem. I would measure draw (in mA) across fuse C1 w/ the car locked and unlocked.
I haven't studied the 996 wiring diagram, but a trusted source told me
the MFI-DI relay
(position 1) 141.951.253.B next to the ECU is in line w/ fuse C1, but would think you'd wanna make the measurements I mention above before you start replacing relays.
The system should power down to less than 50ma in a matter of minutes, usually less than 30ma , and even faster if the car is locked via remote.
If anything is drawing over 50ma after a few minutes (10min-30min), it has a problem..
Faulty meter leads were giving me faulty readings. Sorted that out, and found the true source of the draw - the rear spoiler circuit. Also for some reason there is always voltage at the fuse socket - am I wrong or is this not supposed to be a live circuit with the key out?
Maybe, just maybe, the little light on the engine lid in the engine compartment is staying on? Same wiring as the spoiler circuit. There is a microswitch on the engine lid latch that turns it off and on. Maybe lift the engine lid and pop the latch closed with a screwdriver and see if the light goes out. Don't forget to "unlatch" the latch before closing the engine lid.
So from what you're telling me if use a screwdriver to latch the latch with the lid up the light should go out? Because if that's the case, that's the problem.
EDIT: took out the bulb, still have the draw.
The immobilzer/alarm system also monitors the engine lid latch constantly. I would still use a screwdriver to pop the latch closed and see what happens. Sorry, running out of ideas.
So the trunk latch is also the light switch, like the door latches are for the doors? If so, that's at least one problem, I just want to confirm there isn't a separate plunger.
Sometimes I'm pretty smart and sometimes I'm a complete idiot. This was one of the idiot times. After checking all the spoiler wiring, relays, ground....I realize I counted wrong and the problem is fuse D8, not D7, i.e. the radio, so I'm guessing the bluetooth module that I have piggybacking off of it.
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