jay@EZimmoblock.com

If it takes 15 seconds to turn off, this indicates the immobilizer is ARMED. No comms to the ECU will be possible and the the car will not start. So far, normal. If, after using the FOB, the car starts, it means the immo is disarmed and your scanner should be able to talk to the ECU.

When the car is running, can your scanner communicate with the ECU?

systemsc

As mentioned before, first determine if your scanners can find any ECUs, e.g. ABS, CCU, Alarm, etc, and NOT the DME ECM. If not, then two possibilities, tester problems or the "K" & "L" lines are hung-up (wiring problem).
You can always bypass the immobilizer by disconnecting it and jumping pins 9 & 11 on the immobilizer to access the DME ECM. Obvious, the vehicle can't be started, but communications are possible with an appropriate tester.

The immobilizer data, e.g. flash memory, can't be accessed via ANY tester, i.e. it's only a pass-thru device to the DME ECM while communicating with the alarm ECU.

You mean Autel? Most all low cost generic scanners are JUST for OBDII vehicles, and only for the engine ECU (ECM).

jay@EZimmoblock.com

The test showing that the FOB works repeatedly and reliably, then some time later completely stops working is interesting. I agree that it probably rules out the FOB, (and FOB pairing to the immo), and since it works reliably at a respectable distance, it likely rules out bad immo capacitors. One thing that can explain this work-good/not-work-at-all behavior is a faulty Key/Buzzer switch. If the switch sticks closed, it will cause the immo to ignore the FOB. There's a simple test to prove this: Next time the car stops responding to the FOB, PULL fuse 11. Make no other changes. Then see if the FOB works.

cobalt

So I cannot get anything to connect to the car Alarm off/on running etc. Even the Autel tablet (corrected my Autocorrect ) which has never had an issue with any 993 before will not connect under any conditions so far.

Jay thank you so much that sounds like a good place to start at least with the alarm/fob. I will report back later today with what I find when pulling the fuse. Off to Dr and then playing with this nightmare.

May thanks to everyone.

jay@EZimmoblock.com

So you may have 2 things going on (FOB, Scanner Comms). If you get the FOB working, it'll be easier to continue troubleshooting. Keep us posted.
And BTW, if the key switch is stuck, the door LEDS will still flash when you press the FOB - the immo just won't toggle state.

cobalt

So I had a moment and pulled fuse 11 the only change is the interior and frunk light no longer flashed as the alarm sounded. Now I cannot get the alarm to disengage even with the key even after I replace fuse 11.

I pulled the negative battery cable and will revisit it later. I did notice once the alarm sounded I get 2 flashes on the door space 2 flashes. However now I am stuck as I can't unlock the system no matter what I do and that alarm is annoying.

I found I had a copy of the factory 993 OBD II diagnostic manual I will see if I can find anything in there that might help. They do note that there are some OBDII systems with OBD I ports for earlier cars but I need to read through the 3" binder of info before I know more. I'll report back when I find out more.

I will also pull the clock and check the flasher and see if there is any water issues there. The car has a lot of filler around the front windshield so most likely ahd rust and possible some water although so far the interior is quite clean.

jay@EZimmoblock.com

So just to be clear...you got the car into the mode where the FOB would not lock/unlock the doors, then you pulled F11 and tried the FOB (without doing anything else) and the doors still would not lock/unlock? F11 controls those lights so those not working with F11 out is expected. You said earlier that you could somehow clear the alarm with the key? I didn't think that was possible (can't on mine anyway). What is the procedure?

Since it sounds like you'll be setting the alarm off regularly before this is solved, it might be worth getting access to the alarm unit under pass seat where you can reset the alarm by temporarily grounding the BR/GN wire on the yellow connector. If it's easier, you can also get at that wire at the back of the immobilizer (also BN/GN).

systemsc

Actually, there were non-OBDII vehicles (OBDI) with 16 pin diagnostic ports. Check the DME ECM under the driver's seat, i.e. the OBDII DME ECM vehicles have an 88 pin connector versus a 55 pin connector.
Here's the link for reseting the alarm ECU; https://rennlist.com/forums/993-foru...ing-issue.html

cobalt

Yes I did paragraph 1 and nothing. Now the alarm will not turn off at all. It did before I pulled 11. It would shut the alarm and reset after holding the key to the left for a prolonged period Now it will not do anything but make noise and flash lights.



This is one of the key issues. I was hoping to diagnose it before having to drill out the hardware the seats are clearly factory installed and I cannot remove the inside cap screws on either seat. No matter if I try using a handheld Impact driver to loosen the screw it is stuck. Even using the proper tool with the indent. So I will have to drill them out. I was hoping not to have to do this but I am guessing I have no choice. That was my first thought before the OBD tester but I am just ending up with dead ends. It is like a trip to Home depot. Always a dead end and need to reinvent the process or project.

Looks like I will be drilling these out before I can progress.

jay@EZimmoblock.com

Resetting alarm by rotating the key to the left in the door lock and holding for a prolonged period is a new one to me. The FOB should be the only way to reset a triggered alarm. Does the owner have a good history of car, i.e., possible non-OEM mods, equipment, wiring, etc? Do you know if he was ever able to get a scanner to communicate? Puzzling......
BTW, you said the radio was removed and the harness was cut. You might want to check where that green chassis wire is going - I believe if no radio is in the green wire needs to taped off or it's an alarm condition.

Bill Verburg

Are you sure that is what it says, if so it makes no sense

What is true is that the early('94 & '95) OBD1 cars had round OBD1 ports , sometime in '95 they switched to the rectangular OBD2 ports, but still have OBD1 2.10.1 Motronic

Just for future reference
all n/a RoW are OBD1 Bosh 2.10.1, 55 pin harness and 1 O sensor, early use a round OBD1 port, late a rectangular OBD2 port

all 993turbo MY96 on are OBD2 Bosch M 5,2, 88 pin harness and stereo paired (4) O sensors

all US n/a MY96 on are OBD2 Bosch M 5,2, 88 pin harness and stereo paired (4) O sensors

systemsc

[QUOTE=cobalt;18635145]Yes I did paragraph 1 and nothing. Now the alarm will not turn off at all. It did before I pulled 11. It would shut the alarm and reset after holding the key to the left for a prolonged period Now it will not do anything but make noise and flash lights.





This is one of the key issues. I was hoping to diagnose it before having to drill out the hardware the seats are clearly factory installed and I cannot remove the inside cap screws on either seat. No matter if I try using a handheld Impact driver to loosen the screw it is stuck. Even using the proper tool with the indent. So I will have to drill them out. I was hoping not to have to do this but I am guessing I have no choice. That was my first thought before the OBD tester but I am just ending up with dead ends. It is like a trip to Home depot. Always a dead end and need to reinvent the process or project.

Looks like I will be drilling these out before I can progress.[/QUOTE]

First do with post #26 implies, i.e. look for the number of O2 sensors.

cobalt

Yesterday was a bit crazy the owner of the car stopped by and is looking to have this car in tip top shape. Something beyond my scope in my garage. He is a very interesting individual and is well known for his Interior Designs so visual is key for him. It looks like I will do what I can and send the rest off to be completed. This car needs 70-80 hrs min of my time before I can send it off for the clutch.

It truly is. shame that BaT cars can be so poorly advertised and sales tactics like EVerything gone through No expense spared can be used by a dealership and be the farthest thing from the truth.

The interesting news. I was able to get the car to cooperate for a little. I tried plugging in the OBD diagnostic tool and connect to the ECU. It only happens with the engine running. I have limited diagnostic experience with OBDII systems so all I was able to read was the emissions diagnostics which were surprisingly good. So I guess there is a cable for my KTS301 that replaces the round connector I do not have. I will look into sourcing one for the future I might need it again.

I mistakenly assumed the book I have will cover all OBD systems but it only is for diagnosing emissions and the round OBD port is for targas only for some reason. FYI is it true that Guntherwerks only uses 993 targas to build their cars?

I did start from ground one so I put a load on the supposedly new battery installed by the seller and it shows week even after a tender on it shows lightly week. I don't know if this has anything to do with the issue as I tried testing everything with and without a tender connected. If this has anything to do with the issue I will kick myself for believing anything I read from this seller and for making the classic mistake of ruling something simple out because of an assumption of it being brand new. I had a similar issue years ago when the brand new CDI box I purchased had the same issue as the one I repalced and assumed it was good since it was new. That one baffled me for a year. But my SC was in A1 condition when i was done.

I did find out that the sunroof seal which was so poorly installed is also just part of the issue I repalced the seal and then it wouldn't quite close correctly only to find the transmission and cables need replacing. Ironically I hate the sunroof and slick top converted my C2 so I didn't have to mess with them but it looks like I will be reworking that as well.

So back to the Alarm I am still stumped and have seen no progress. It never acts up the same way twice but it always acts up if allowed to sit for any longer than 20 min without any activation through the fob or ignition. I have to assume that some 28 year old capacitor or component is giving me the issue so I will be drilling out the seat today. It will make fixing the sunroof easier as well as I don't squeeze into the rear with the seats in the car anyhow.

So this cracks me up that someone could try to pass this off as a replaced seal.

Before:


They cut the seals and then realized they were short so pieced little pieces in place to make it look like there were no gaps.

That looks original right LOL

After:


I have done a half dozen of these and the quality of the seal has gone down hill. They used to be heat sealed together. Now they are just pressed and steamed it appears and the nylon piece easily floats around so much harder to install perfectly than before.


Again I appreciate all the help I will see what else I can find and report back after i have the seats removed.

jay@EZimmoblock.com

Correct - if you started the engine, the immobilizer is disarmed. When the immobilizer is disarmed, a relay inside it connects the OBD port to the ECU, allowing you to read emissions data. So the immo is doing it's thing and the ECU can communicate with a scanner. The FOB sounds good too. Still something crazy with the alarm unit, but judging by the condition of the car, and unknown history, who knows what evil lurks...

PS: Still don't know how you were able to silence the alarm with the key, but if you found some secret technique, please share!

cobalt

Sadly I guess it was a fluke and worked multiple times but once I removed fuse 11 it would no longer silence the alarm as it did before. I am leaning towards the alarm module as being the culprit. Although I don't want to jump to quickly to conclusions.