13 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH996 C4 Cabrio Battery Drain Help
Reported or suspected cause
fuses...read the current draw...no change?, replace fuse
Suggestion or failed attempt
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
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Discussions that suspect a cause
1
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Suspected cause
3.- Remove ONE of the suspect fuses...read the current draw...no change?, replace fuse
Leading evidence: 'fuses...read the current draw...no change?, replace fuse' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'fuses...read the current draw...no change?, replace fuse' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check draw' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
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Suggestion
Also see if you can check the draw with the car unlocked and then locked.
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Suggestion · Original poster
If I disconnect my ampmeter and then re-connect, the parasitic draw drops to 40-50ma which is right there it suppose to be.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Suggestion
3.- Remove ONE of the suspect fuses...read the current draw...no change?, replace fuse
Replace although i didn't think this would be the problem
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Suggestion · Original poster
I pulled the starter wires, no change although I didn't think this would be the problem but while the alternator was out you can reach the starter wires pretty easily.
Replace although i didn't think this would be the problem
No successful repair reported for this finding.
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Reported fixes
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Unsuccessful attempts
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Discussions
Read evidence and context
Discussions that contain suggestions
1
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Suggestion · Original poster
I pulled the starter wires, no change although I didn't think this would be the problem but while the alternator was out you can reach the starter wires pretty easily.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
Have a battery drain on my 2000 996 C4 Cabrio that will drain the battery in a day or two and enough drain to ignite the test light when testing for drains
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0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
Have a battery drain on my 2000 996 C4 Cabrio that will drain the battery in a day or two and enough drain to ignite the test light when testing for drains
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
13 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
7 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
I have unplugged the alternator with no change in the drain
Hello
Got something that I have pulling my hair out with. Have a battery drain on my 2000 996 C4 Cabrio that will drain the battery in a day or two and enough drain to ignite the test light when testing for drains
Here is what I have done:
1. When pulling individual fuses the drain will not go away but.... When pulling multiple fuses it will. It takes pulling of 4 different fuses to for the drain to go away. Here are the 4 fuses:
- B1, Instrument Cluster, Tiptronic, Diagnosis, ASR/PSM button, Conv top control unit
- D8, Radio
- D1, Power Windows Front
- D4, Power Windows Rear, Cabrio
2. I have unplugged the alternator with no change in the drain
3. I have unplugged the ignition switch with no change in the drain
4. Unplugged window switches with no change in drain
Any ideas of what it might be?
The best way to do this (car off and key off):
1.- place an ammeter in series with the negative pole
2.- Read the current draw
3.- Remove ONE of the suspect fuses...read the current draw...no change?, replace fuse
4.- Repeat 2 and 3 until you find the fuse that reduces the current draw significantly
5.- Troubleshoot that circuit/wiring with the schematic/wiring diagram
Yes that is good advice but I suspect that by pulling individual fuses you will not see a significant difference until you pull all the 4 that I discuss, but I will try it
Thanks
..I doubt ALL 4 are drawing "too much" (it is possible, but I doubt it).....I think ONE of those fuses will give you the biggest draw.....then you start troubleshooting that circuit....
Also see if you can check the draw with the car unlocked and then locked. The reason is if the car is unlocked, the car stays in the "ready" mode. When you lock the car, the DME and instrument cluster power down. Just the immobilizer remains active listening for a remote key. That also shuts down after 5 days. You might also check that the frunk and engine lid lights go out when closed. How? Put your cell phone in video recording mode and leave in the compartment.
OK, here is the update on the issue.....
Hooked up milliamp meter and at rest, with all lights confirmed off we have 110-120 milliamp draw which is about 50-70 too high. I have a 997 cabrio here as well and at rest it is at 55-65ma.
I pulled ALL fuses in the fuse box, one at a time and all together, no change
I pulled all relays in the fuse box, one at a time and all together, no change
Here is the ironic thing..... If I disconnect my ampmeter and then re-connect, the parasitic draw drops to 40-50ma which is right there it suppose to be. As soon as I open the door and then shut it and wait for the car to come back to rest it goes back to 110-120ma at rest, so something is staying on until we completely disconnect the battery and stays off until its energized again by the door being opened.
So its not related to any fuses or relays..... I pulled the alternator no change at all, still at 110-120ma,
I pulled the starter wires, no change although I didn't think this would be the problem but while the alternator was out you can reach the starter wires pretty easily.
One thing thing that I was thinking is the fuel pump since I believe it it energized with the door open.
How old is the battery? Has it been tested? These batteries will provide enough power to start the car in the morning and will fail without warning when you go to start at lunch.
In my experience, a draw of 120ma at rest should not discharge a battery in 48 hours...unless there is a problem with the battery.
I used to have a 1994 MB 420E that would draw 120mA at rest...and the car sometimes would sit for a week or more....and would fire right up.
However, based on your findings, it seems there is something wacky going on...when you open the door, expect a higher draw for a few minutes, as the inside lights will stay on and eventually shut off....keep in mind that if you have your frunk open, the light will be on too...I would take the lights out and measure again.......
Should be under 100ma in general, because it will be dead in 1.5-2.5 weeks. The issue is that I have a 997 that has 1/2 the parasitic draw so there is some issue with this 996. I have tested a lot of these and generally anything over 100ma signals a problem.
40-60ma draw the car can sit almost a month before the battery is too dead to crank over.
Your timing is spot on, So I lock the car and wait 30 minutes and the draw goes all the way down to 20ma which is crazy. So the car draws over 100ma unlocked and 20ma locked. I guess the 996 were made to sit locked which I always hate to lock a car that sits long term.
997 has 40-60ma unlocked, haven't tried it locked.
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