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Discussion summary
YOUR RESEARCH996 electrical issue, I am stumped
Leading reported evidence
Check codes
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed · Original poster
My Icarsoft reader came in today and I checked the codes when I got home.
Leading evidence: 'Check codes' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'short .don't know your meter' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check behind the pass' (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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Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed · Original poster
Checked the drivers side crash sensor from when the car was torn apart a few weeks ago.
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Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed · Original poster
Cleaned with deoxit d5, agitated with a makeup brush and blew it dry.
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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Performed · outcome unconfirmed · Original poster
Fuse blew with immobilizer disconnected , fuse blows with the radio disconnected.
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Performed · outcome unconfirmed · Original poster
Disconnected the negative terminal on the battery and waiting 30-45 minutes.
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Suggestion
Then individually with fuse removed, one by one disconnect/unplug each component on the circuit and check for a short to ground in the circuit and device, with a MM.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
short .don't know your meter
No successful repair reported for this finding.
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Identified cause
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Suspected cause
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Read evidence and context
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Suspected cause
.Likely a short .Don't know your meter but when set to ohms and probes shorted to each other that's a short reading .The output fuse side and car ground probably gives same reading .Using prorsche tech steps fingd the root cause .
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.
56 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261027T082735Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
996.1 C2 is the vehicle.
I am stumped on this one guys..
-Was driving home, everything working fine then suddenly I got a brief airbag light and lost my radio. Car drove fine the remainder of the drive home. Now car is blowing fuse e1 as soon as I turn the key and the car won�t start. No noise at all when cranking.
- changed ignition switch (still difficult to get key in)
- tried removing the radio harness, still blew the fuse and wouldn�t start.
- all grounds look fine
-clutch switch engages fine
-start/lock relay (#7) in rear relay support was replaced, didn�t work
-no other fuses are blowing
-battery reads 12.8v
-is this an immobilizer issue? Maybe the airbag control module? Car is not a cabriolet and hasn�t had any water damage.
any help appreciated!
Any recent work done to the car -radio -Instrument cluster ? Ignition switch replaced after episode ?Key should slide in no effort .Blowing fuses is a dead short good bet pinched wire .Finding it will take a meter wiring diagram and patience.
First thing I'd do is replace the ignition switch. The fact that the key is hard to turn points to it. When those things go all kind of weird things can happen with the electrical system.
I assume when you say "changed ignition switch" you replaced it with a new 1..?
When u say turn the key, does that mean the first position of key in ignition switch blows fuse..?, or do you mean when turning key all the way to try and start car..?
Well, you say the starter is operating and "cranking" the motor over, but not starting...?
If I understand that correctly, then IIRR, the immobilizer is working or it wouldn't crank over.
Did you log any fault codes to start troubleshooting with...?
If not, Might have to isolate your problem of blowing fuses.
Start by finding out exactly what components are protected by fuse E1.
Then individually with fuse removed, one by one disconnect/unplug each component on the circuit and check for a short to ground in the circuit and device, with a MM. Reconnect and move to the next circuit/component/device till you find the short. As others have said, could be in the wiring to components or plugs/connectors, so check the circuit carefully with a MM.
jmo
thank you for your help. I replaced the ignition switch with a new one. Fuse E1 is blown as soon as I turn the key from position 0. When I try to crank I get no noise. Could be the battery but the battery showed as healthy.
no previous work done relating to anything other than me replacing the ignition switch. I ordered a Haynes manual but can�t find the wiring diagram at the moment. Do you have a recommended online source for wiring diagrams?
thank you! I tested the voltage between pin 1 in fuse E1s slot and ground (0.18v). I then tested the resistance between the 86s pin on the electrical connector for the ignition switch to pin 1 on E1 (9.xx ohms) I�m thinking either the wiring harness for the ignition switch connector needs to be repaired somewhere or the alarm control
unit under the driver�s seat is connected. I�m checking the unit under the seat tomorrow. Hoping for a loose ground or bare wire.
I would disconnected the alarm control under the seat , then turn the key on and see of fuse E1 blows, if it doesn't, then open up the alarm control unit to see if it is wet /damaged/ burnt..
They can get wet without you even knowing it...
If the fuse E1 still blows with alarm control disconnected, I would locate splice/weld point 85, and separate all circuits, then reconnect them one at a time to see which one is blowing the fuse, then follow that circuit..
You should have zero resistance between pin 86s
and fuse E1 in fuse panel. Not sure what 9.xx signifies. Should read 0.00 on meter.
Might have damaged plug connection at ignition switch would be my guess. Or wire is somehow compromised.
you could test by leaving switch connector off and just connect terminal 86s to fuse E1 using a jumper wire. Leave all consumables connected on other side of fuse. Turn ignition to run position.
For safety you should try to disconnect the factory wire at both the connector and fuse panel.leave fuse out initially. Then test for voltage.
Also would be prudent to see voltage at E1 before fuse using factory wiring.
As stupid as this sounds, I had my car towed after I replaced the ignition switch with a new one. I had similar issues (I didn't blow any fuses) to you. Shop replaced my ignition switch again and all was normal again. I wouldn't have believed it tho.
Porsche tech provided the steps to identify the problem .The fact that the fuse blows when the key is on is verification that the fuse is getting power .The problem is that the load is greater than the7.5 amp fuse. .Likely a short .Don't know your meter but when set to ohms and probes shorted to each other that's a short reading .The output fuse side and car ground probably gives same reading .Using prorsche tech steps fingd the root cause .
I am following Porsche tech�s advice and it is greatly appreciated. Fuse blew with immobilizer disconnected , fuse blows with the radio disconnected. Fuse blows with headlights out of the vehicle (eliminates DRL short). Instrument cluster is fine. I�m assuming Cu Info and Cu Alarm is the immobilizer under the drivers seat?
New finds.. after searching the FCC ID this is an old Lo- Jack anti theft unit powered by a rechargeable battery. Going to remove it tomorrow along with a few other sketchy things I have found relating to the aftermarket radio.
This is the back side of the cigarette lighter converted to a usb connector. Looks great�
This is the back side of what looks like a bass ****.. I removed the clicking **** but you can see it is obviously a bass **** and obviously dangerously wired by the PO.
no dice with disconnecting and reconnecting the headlight switch. Would a corroded ground under the seat cause this issue? I had a ground under the seat that was corroded and I cleaned it but haven�t tested yet (ran out of time). The wiring diagram associated with fuse E1 doesn�t mention the airbags or grounding the seat but the airbag light did flicker once before I lost my radio while driving.
No, a bad ground in a low amperage circuit won't cause your problem, imo. But at this point you never know, try it and see as it needs to be repaired anyhow.
After seeing above pics of all the aftermarket wiring and devices you've got in there, I'd start by disconnecting all of it at least for now till you find your short. Try to put all the wiring back to oem.
Obviously, check for any bare wires/connectors/terminals while you're in there taking out all that 'stuff.
jmo
Do i understand correctly that you changed your ignition key tumbler switch and shortly after that you had this issue?
I have taken note in my work life and in dealing with equipment issues of many different types, and this also can be true for vehicles is:-
go back to what you just touched or dealt with before the issue, and look at not only what you changed but adjacent items you may have inadvertently touched whilst in there, like wires that were moved or pinched.
but all that aftermarket crap can be a real problem.
Negative. I replaced the ignition switch after the situation happened. My Icarsoft reader came in today and I checked the codes when I got home. Maybe a simple airbag light clearing will do the trick..
And what do you know� Good ol� Term.86S. I bet the passenger side airbag came unplugged. I replaced the window regulator a couple of months ago. I�ll check there first and report back tomorrow.
My apologies. Not a plug. A sensor. Can�t find a write up covering how to access the sidebag sensors. I know they are under the seatbelt tensioner but not sure if I need to take off the entire rear side panel to access it. Any help appreciated.
ended up removing the airbag control module, Alarm control unit, and DME. Gave them a good cleaning and it started right up. Fast forward a week later, same issue as I was coming home from the grocery store. Tried the same remedy, nothing. I guess I�ll send the alarm control module in to ECU doctors.
Unlikely the problem lies there, in my opinion. Having seen the pictures of the aftermarket stuff as well as you mentioning passenger door lock, I'd do as suggested by previous contributors. If you have checked behind the pass. door panel, let us know please.
The side impact crash sensor is located in the door sill not near the belt real, see page 69-13 in the Bentley manual.
If that yields no result, you can still send the ecu to the ecu doctors.
the problem was fixed for a week and I�m back to square one. Checked the drivers side crash sensor from when the car was torn apart a few weeks ago. All I�m getting now is �signal converter faulty� and �wrong key or transponder� codes. These have been codes I have had for a while but did not have issues with the vehicle starting. About to remove passenger side door panel but I am only getting an air bag fault from the drivers side buckle (seat is removed).
lol...The signal converter is a small black box that is mounted to the ignition lock/steering column lock, it has two small wires that go to the plastic circular "antenna" around the key cylinder, it reads the transponder, then sends the signal to the signal converter who sends the codes to start to the DME..
Check the connections on these two things, It's probably where your problem lies ( since you have codes for them)... most of the time I have found these connections loose and causing issues, there were no codes...
changed key blades and now all I�m getting is the signal converter faulty (code 39). I made sure the connection was secure on the back of the transducer (signal converter) before buttoning the interior up the first time. It may need a little contact cleaner and deoxit d5 treatment. I�m going to make sure the transducer box is securely mounted as well. I believe I remember securing it with a plastic Phillips head that tightened with a little quarter turn. Considering the vehicle�s age It may have come undone. I�ll tackle it tomorrow. Thank you for your help.
No idea what is causing the fuse to blow. Still waiting on the transducer box (on top of the steering column) to come in. I tried unplugging, cleaning and plugging back in and the fuse still blows.
I unplugged the immobilizer. Fuse still
blew. Plugged it back in and removed the central locking switch. Fuse blew very hard. Unplugged radio harness, fuse still blew, instrument cluster works fine. I think that covers splice/weld point 85
Again, you failed to follow my advice, disconnecting the components at the end of the power lines is not the same as separating and disconnecting all the power lines at the splice/weld point....
Effective/efficient troubleshooting of difficult shorts has to be done in a systematic procedure...
A wiring diagram will show you the general location of splice 85 in lateral and longitudinal area, it is in the drivers floorboard area,but you will have to trace it from the fuse E1 to find the splice 85, then separate and disconnect all power lines.. (You may even get lucky and find the short while tracing/finding the splice 85)...
Just be careful and deliberate,, the only thing worse than troubleshooting and finding a short circuit, is troubleshooting and finding an "intermittent" short circuit...
Most likely is but needs to be positively confirmed by tracing to fuse E1, then all power lines separated and reconnected one at a time to confirm which one has the short on it, then trace that power line to the short circuit...
Careful and deliberate testing/tracing is required to keep from going astray...
busy day today, did not get the chance to dive in. From jumpychunky�s photo is looks like splice welds are very close to the fuse box. I�ll remove the fuse box and get behind. Will this splice weld most likely be in the large bundle of wires to the left of the dead pedal?
Yeah, bridge point 13/1 is connection point for�. Info system, daytime running lights and roll over sensor for Cabrio. Do you have those options?
86s also feeds radio, radio alarm, instrument cluster and alarm control unit.
If first three options aren�t installed on your car.
Then you should only be concerned with the last four. You can disconnect the last four and check bridge point 13/1 and isolate wire 86s.
once done turn ignition on and check for ground short in wiring by bridging fuse holder E1 with multi meter and check for voltage.
Sounds like a direct short...
Might want to get 1 of these, they're inexpensive and pay for themselves quick after going thru a pile of blown fuses...
I've got a 3 amp and 5 amp.
Always used these when troubleshooting a blown fuse problem in shorted control circuits, or where ever needed troubleshooting a lv short.
These mini circuit breaker's spade connectors plug right into the fuse socket. The 5amp will take a good few minutes to blow if amperage is close to >5. If amperage is over 10 will blow in a under 5 seconds. 20 amps will blow in a second or 2. Same type stuff just a little lower for the 3 amp. They are 'slow blow'.
Update for anyone following. The fuse is no longer blowing. A previous owner/installer had tapped into the 86s wire on the original wiring harness, and bridged that connection with brown (ground) and ran the built in k40 laser jammer and lo jack theft deterrent system. I disconnected the bridge and isolated the wires until I can really get in and disconnect everything once and for all. The radio is working and fuse E1 is good. Now the car is not detecting the immobilizer (I unplugged it because I was sitting on the floorboard to diagnose all of this and didn�t want to crack it. Disconnected the negative terminal on the battery and waiting 30-45 minutes. Hopefully it fixes the final gremlin. Attaching pics of the hack job from one of the previous owners.
Here they ran out of clear speaker wire and decided to change to this white wire. Looks great�
See where they took the clear wire and tied it into the orange (86s) wire. Then routed the ground side to brown.
This is where the white wire, antennas for the lo jack and k40 laser jammer all met up to go up to the instrument cluster.
thank you! Immobilizer unit is set and the car starts. Had to take the the jacket off of plug 1 of the immobilizer harness. Cleaned with deoxit d5, agitated with a makeup brush and blew it dry. Did the same for the DME. Now to get all of these wires cleaned up. I�m thrilled. Celebrating with a whiskey. Thanks to everyone for the help.
Glad you got it figured out
.
This is a classic example of why I try to avoid buying cars with aftermarket electronics installed. There have been far too many times that a ''professional" install was a complete hack job.
The aftermarket strikes again.. how these installation places were in business amazes me.. well done for sticking at it... you now know more about 996 wiring than most lol
Great instruction and impressive perseverance! I hate dealing with electrical faults but then having to deal with a bunch of horrible aftermarket hack-jobs to the harness is a whole nother level of madness!
Well done
I�ll hang on to the knowledge I gained throughout this process and try to help anyone that needs it. Looking back, I am glad I stuck with it and had the chance to learn so much about the car. I�m now battling a gearbox noise. The previous owner had a muffler bypass installed when I bought it, you couldn�t hear anything gearbox related due to the drone. After the fister mod/orange cap mod I definitely can hear the car. Problem is, not sure if it is normal or not. Posted a thread about it if you�re interested. Cheers!
