After turning off, cannot start again for 2 - 3 minutes, after door lights come on!!!

Restoring a 2003 996. Never had an issue turning it over, and when pressing the key in the past I could lock the doors and hear the beep beep to lock and unlock. Don't know if related, but I had the car battery disconnected for about 2 weeks while I did work on the car. I finished that work and reconnected the battery. Everything worked but I noticed that I no longer could unlock/lock anything using the button on the key, even though the light would flash. After starting and running the car, then TURNING OFF, 90% if the time upon inserting the key, everything would light up on instrument cluster, but nothing happens when I try to start....the overhead light, the door lights will not light up, and I cannot use the frunk or rear compartment release buttons. (PLEASE NOTE: I cannot use the key to open/lock/open frunk EVER now. But the starting issue is ONLY after running the car and shutting down and then trying to start again immediately!) If I wait 3 - 5 minutes before trying to start, it will then finally turn over as if its some sort of countdown. ALSO I KNOW it is ready to start when I turn the key to on position the overhead light and door lights suddenly COME ON!!! While everything else is lit up, the door lights and overhead light WILL NOT light up when the engine is unwilling to turn over.....but once they suddenly turn on, that is my clue that next attempt to start WILL WORK and the frunk and rear compartment release buttons come to life as well. I hope this is not too confusing, I tried to describe it best I can. I'm not afraid to take it out and drive and stop, because this has happened enough that I KNOW if I wait 3 minutes, it WILL START!!! Anyone have an idea of what the heck is going on????

I think there might be an issue with your immobilizer module. During those 3 minutes of not turning over, are your overhead lights unable to be forced on? It sounds to me that your overhead lights are currently in �door mode� which light up when the door is opened. What if you try to lock the car using the dash button, while the car is unable to start? Do the power locks work then? Do you have a PIWIS or similar? You may want to check for any trouble codes.

Hi there, the overhead light switches will not work, nor will the door locks, wondows or any button on the center console. I cannot pop the hood or engine compartment. Only the Radio and the HVAC controls work. The PCM off button was lit up but I could not change it. I just had it running for 15 minutes outside, turned it off and tried to restart and sure enough nothing but radio and HVAC. When I turn the key the instrument cluster lights up with all the warning lights as it normally would on a startup but the engine does not turn over. Tried everything including hitting things, jumping on seat, tapping the key fob but nothing. It really comes down to timing, let it alone for 3-5 min and bingo everything is good to go! My inclination is the immobilizer, but want to be sure. Again the key used to work properly but everything started happening after I had battery disconnected for a week to do work, and now key does not work even thought I get the flickr light and changed the battery. Cant be a coincidence. Is it possible something changed after not having the battery connected for a week? Also to be clear, even after being able to start the car, the key fob still will not work to open trunk or engine compart

There r 3 fuses that supply power to the immo. 2 in the footwell and 1 on the unit itself. Check all 3, sorry dont have time to look up the locations. I had a length thread in my immo which had bad tracks. Ecudoctors was able to reflow the unit. They will do a diag for $99 if u need to send it out. It kinda soulds like its in sleep mode. Try locking and unlocking using the key in the door, then try to start the car. See if that wakes up the remote and immo?

Thank you I'll try that and report back. PS - As per my update on previous post, even after I can start the car, the key still operates in the same manner. In addition I just thought that I should pull the driver seat out and check everything. I had pulled the seat when the battery was out so I could work easier on the dash. Maybe something got loose on the immobilizer?

1st place i would start. My antena coax wire falls out all the time.

It would be interesting if you timed it using a stopwatch.

I'd be interested as well, I'll give it a try later and report

Can you explain further please. Im not sure I'm understanding. An antenna on/in the car or in the key itself? I've been doing a lot of work on the dash and it was a #*)$& putting all the wiring back in place, maybe I left something out!

Some immobilizer modules have an antenna that plug into them. like so: http://986forum.com/forums/performan...-cable-do.html Mine doesn�t have one.

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well of course it proved me wrong, it "allowed" me to start after just 20 seconds....go figure! I'm trying all sorts of things to find a pattern, so far no luck. Going to take the seat out on the weekend and look at the immobilizer. Wife is telling me I'm spending too much time with my 996! Is that possible?

If she isn�t already jealous, she will be when you start spending more money on it� which is likely if your immobilizer is the culprit. edit: Thanks for timing it for me. The randomness of the intervals make me think that something is failing, as opposed to an anti-theft program - like when you lock yourself out of your iPhone.

I was looking at some wiring diagrams of the immobilizer module today and I hypothesize that your module�s internal relays may be malfunctioning. Take a look at this photo: https://i.ebayimg.com/images/g/FoQAA...Hw/s-l1200.jpg Those arrows point to the internal relays. If you�re feeling adventurous, you could remove the cover to your immobilizer module and reconnect it to the wire harness. Then place your fingers on each individual relay while you turn your key to position 2 and wait for your overhead lights to activate. If a relay clicks on when the lights return, then you�ll be able to pinpoint the problematic one. And while you have the seat off, I would check the stability of your module�s ground wire connection. Give it a wiggle and/or undo it and fasten it back securely. I would actually do this first, before you go to the trouble of disassembling your module.

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Thank you for the info and photo. No problem, I've been known to replace capacitors in monitors just to avoid tossing it away! Yep, I'm thinking that this has something to do with me taking the seat out and working in that area. Everything points to the immobilizer and makes sense that something went wrong. Will take seat out on the weekend and hopefully resolve this. Thanks!

Ignition switch.

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Honestly i hate throwing parts at a problem but this is a real possibility. i see 3 directions u can take assuming u dont find something loose under the seat. Oh and pull the cover off the immo to see if ut has any water damage in the board. 1. If u have a piwis u can spend a few hours back pinning and checking wires 2. Send the immo, dme and key to Ecudoctors for the diagnostics 3. Burn it to the ground

This is a cheap solution for sure. So many examples of what is explained above all lead to the ignition switch. I would recommend it.

Nope on the ignition switch. That was the first thing I replaced on the car. And yes, the old one was the source of MANY odd issues! I think its the immobilizer. Will pull seat on weekend and look at it and report back. Thanks for all the suggestions.

you can see my restoration progress here: https://rennlist.com/forums/996-foru...ggestions.html

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I replaced my ignition switch with a URO one. Was on car for 4 days. Worked fine. Decided to replace again with the audi/porsche part. Replaced worked fine. 5 years later (5000 km. not 50000 km) , car would not start. Air bag light too. I kept resetting the air bag light. I changed the ignition switch to the URO one. Still not starting. I gave up. Had car towed to porsche specialist and explained what had happened. He chased it for a while. Refused to listen to me. He went ahead and replaced the switch again. ALL WAS GOOD AGAIN. Just saying.

Quotes source post: 20196453

Well, having come from the tech industry, I would never say 100% no it cant be that, but I'm still leaning towards the immobilizer. I removed the seat on the weekend and took out the immobilizer and inspected it. The 3 ground wires looked a little corroded, so I cleaned them up and put them back on. I removed the fuse from the immobilizer and it tested good but again it was really tarnished so I sanded it down and put it back in. The antenna looked ok, unplugged and plugged back in. I opened the immobilizer and did not see any signs of water damage, looked perfect including the capacitor etc. Put it all back together. Now here is the strange part. Had NO ISSUES starting stopping starting! Thought I fixed the problem but still the key would not work by pressing the button. However no issues starting and stopping the engine. Thought maybe it was working better, because before when I turned off the car I had to wait a few minutes. Next day it seemed better but then it started to do the same thing with the starting, not as often but it was back. All I needed to do is leave it a few minutes and it would start no problem. So predictable I had no issues taking it out to run errands, because no matter how quick I was to go in and come back out, it was enough time for it to "RESET". I'll do more trouble shooting this week with the items people have suggested, but just wanted to update everyone. PS - The ignition switch I purchased and replaced was a PORSCHE part purchased from Sunset Porsche Found this, might be worth it https://www.ecudoctors.com/pages/179-testing-service If i read their symptoms list, it does ring home! PS - Reading their list reminded me of a few other events that might be related 1) The 2 "long" test drives I made this past week, around 10 miles. Towards the end the check engine light came on. When I returned home, with the car running I hooked up my diag tool and it did say immobilizer/alarm as the error code I cleared it and the engine light went off immediately. That seems to indicate that there is an issue with the immobilizer 2) On one shorter trip, I was turning left from a stop sign and half way through the intersection the car SHUT OFF DEAD and I coasted through the intersection. I pulled off to the side, and tried the ignition and it went right away. This has not occurred since. Since taking the immobilizer out and putting it back in after cleaning the contacts, neither of these issues has come up again so far.

That�s great news. It seems like you�re on the right track. The label on the immobilizer seems like it�s had some water damage. If you�re not afraid of a little mess, you could try to pack the connectors with dielectric grease and see if that improves things. It�s kind of a long shot though, I really don�t know if it�ll solve your problem.

The other morning I started it up and immediately there was a check engine light on. Prior to that it started acting up like before and having to wait a minute or so for it to turn over. I was puzzled what was going on, it was as if a few cylinders were not firing. I took it out for a short drive and it stayed the same. Came back and before turning off I put the diagnostics on. Screens below. I cleared the fault with the diag unit and immediately the check engine light went off and the car ran as smooth as could be! Looking at the codes, it sure looks like its telling me the immobilizer is the issue, and like their check list of indications of a faulty immobilizer, check engine light, random rough engine, etc. All these screens are from the fault codes. I'm just learning how to use this, so not sure exactly what it all means, but it seems to indicate there is an issue with the immobilizer. And again, when I clear the fault and reset the Check Engine light, everything runs fine (but start issue remains same).

I dont see any immo faults there. The only thing i see is 3 dme faults, that the engine ecu. Did u read/record those faults?

The screens are all from the 3 faults indicated. When I drill down it brings up Radio Receiver faulty, and that is referring to the radio receiver in the immobilizer. Also in screen 5 it refers to a bad immobilizer. If you search for defective P/N in screen 2 it indeed brings up the Immobilizer as the part number. I'm fairly certain that it is the immobilizer but not 100% sure. I'm trying to determine if the Immobilizer issue is related to the key buttons not working or if that is a seperate issue. This started happening after I started putting the dash, steering wheel and related components back in place. Not sure if I accidentally disconnected something that is related. Now I'm reading that there is a "coil" near where you insert the key that reads it. I think I know what they are talking about, and I remember a small black box near there, and wondering of I reconnected it properly. All I know is that the symptoms all point to an immobilizer problem. When I clear the Check Engine light by clearing the errors in the pictures, the engine immediately runs smooth. However key buttons still do not work. Also wondering if there is a programming issue from having the battery disconnected for a week when I was reinstalling everything in the dashboard.

The immobilizer module receives the signal from your remotes and locks/unlocks the car accordingly. It also governs your ability to start the car, as well as the other electrical bits in your car - like the overhead lights. Think of it like a Body Control Module. At this point, it�s probably best if you send your immobilizer module in to Specialized ECU so that they can diagnose and repair it. I�m sure the price will be a bit shocking. You can also consider deleting the immobilizer module, but then you�ll have to find workarounds to address the consequences, such as: deleting the immobilizer from the ECU, adding a third party remote fob, and wiring in your own body control module.

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Thanks, yes that's the way I'm leaning too. I did get a few prices it wasnt too bad, $175 is what I've found for a diag. I just want to resolve this and get it running the proper way. Given I've done all the work up until now, I am way under the budget I allocated for this project, so I'm happy. If anyone has any other suggestions I'm all ears, otherwise I suppose my next move is to rip it out again and send it off for diags this weekend!

MYSTERY SOLVED!!! Took me awhile to get on this for further diags but finally did. After looking at other possibilities and nothing was obvious, I decided to send away the components for testing to ECU DOCTORS https://www.ecudoctors.com/ in Florida. It required pulling both the ECU and IMMOBILIZER and sending the key along with it. It was definitely not fun pulling the ECU from behind the back seats. The entire time I envisioned the roll over bars popping up and taking my head off, so I tried best I could to work between them. The bottom screws are very difficult to get at but I managed. But if your open to a laugh, the first component I pulled was actually the Convertible roof control module!!! I was swearing like a sailor when I realized my mistake. Ohh well, gave me a chance to inspect it given I have issues with that too! Sent everything away for diags, and got the report back today. I WAS RIGHT!!! The module is DEFECTIVE and the KEY is also DEFECTIVE in transmitting so that explained the lock unlock issue with the buttons. I was almost ready to pull the dash back out thinking I might not have hooked up a wire. Here is the report so you can see for yourselves. So if anyone is experiencing any of these strange issues, its conceivable that your ECU is the issue. Apparently it is a common problem especially in convertibles where water can get in. The report confirms exactly the issues I am having and correspond with the errors I was getting with my diagnostic tool. I paid for the new ECU and a new key which all comes with a 5 year warranty. AND...paid an extra fee of $350 for ECU PERFORMANCE TUNING. The tuning is described here: "Experience the ultimate upgrade for your Porsche with Quantune's ECU Tuning Flash. Engineered for those who demand more from their driving experience, our tuning unlocks:Enjoy an average of +10% increase in horsepower, empowering your Porsche to reach new levels of performance. With+15% more torque, feel the enhanced strength and responsiveness from the moment you press the accelerator. Enhanced Throttle Response: Experience immediate and precise control over your vehicle's power, making for a more engaging and satisfying drive. Quicker Acceleration: covers the thrill of faster acceleration, reducing those 0 to 60 times and making every drive exhilarating. Improved Fuel Economy: Not only does our upgrade boost your performance, but it also optimizes your fuel economy, ensuring you get more from every gallon. Elevate your Porsche's performance and efficiency with Quantune's expert tuning. Feel the difference with every drive." Will have everything back by next week and I will reinstall and test. TOTAL COST $1900.00 but worth it if it solves all the issues. ======================================Your testing summary from ECU doctors is ready for your review. Your test was conducted by our tech, XXXXXXXXXX, and the summary is below. See the full report attached to this email. ✅ Parts That Passed Immobilizer 1 Water Damage/Corrosion inspection: Pass Inspection for Damaged Components (Resistors, Capacitors, Diodes, Chips): Pass Inspection for damage to the printed circuit board: Pass Inspection for damage to the connector: Pass Inspection for damaged solder joints: Pass Remote RF signal receival: Pass Startup Authorization: Pass Door Lock Function: Pass Starter Solenoid Signal: Pass Window Function: Pass Convertible Top Function: Pass Technician Notes: All inspection tests passed without issues. Remote/key 1 Water Damage/Corrosion inspection: Pass Inspection for Damaged Components (Resistors, Capacitors, Diodes, Chips): Pass Inspection for damage to the printed circuit board: Pass Inspection for damage to the connector: Pass Inspection for damaged solder joints: Pass Casing condition: Pass Battery: Pass Battery Tabs: Pass Technician Notes: All inspection tests passed without issues. ❌ Parts That Failed ECU 1 Water Damage/Corrosion inspection: Fail Inspection for Damaged Components (Resistors, Capacitors, Diodes, Chips): Fail Inspection for damage to the printed circuit board: Fail Inspection for damaged solder joints: Fail Fuel pump activation: Fail Fuel injector signal activation: Fail Ignition signal activation: Fail Camshaft adjuster solenoid circuit: Fail Technician Notes: The ECU has suffered significant water damage, affecting multiple components. Recommended for replacement. Remote/key 1 RF signal output: Fail Remote Programming: Fail Remote lock/unlock: Fail Circuit board: Fail Technician Notes: The remote key is not functioning properly; needs replacement components due to failed signaling. Please reach out if you have any questions or concerns. Best,

Nice, thank you for sharing the update. I�m glad to hear that it will be resolved.

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Thank YOU for all your help in diagnosing this!

Well done. Similar service with lower prices in Europe is here, for European readers: https://ecu.eu/