A Durametric scan shows the following fault codes (see below) in the alarm system. The alarm warning light flashes continuously on the clock and the Master Warning Light (!) comes on. All doors, windows, trunk lid, and glove box were closed during the scan.

Here is the interesting part: The alarm system functions completely normally (as far as I can tell) and the car locks, unlocks, and starts with no issues. I do have an Immo-Block installed, which also works perfectly.

In the meantime, I have removed the warning bulb from the clock and have been clearing the (!) with master switch on the center console.

Any thoughts?

 

I vote for a bad ground or corroded connection in one of the pertinent circuits.

Not sure how difficult it is to access the parts, but a good start would be simply to unplug and then replug any connectors.

 

You might have gotten off on the wrong track looking for problems with the Alarm Control Unit (ACU) -- if by "alarm warning light" you mean the immobilizer light (at 4'oclock), that's telling you the immobilizer has a problem, not the ACU.

Have you tried clearing the ACU faults to see if they come back? They might be from an old fault that's no longer active.

A couple of questions
-When the Central warning light (CWL) comes on, do any other warning lights that come on at the same time (other than the one in the clock)?
-Did the "flashing warning light" and CWL start acting up at the same time?
-Any changes made or work done on the car around the time this started?
-After you clear the CWL, does it come back on immediately?

 

Hi Speedy,
Just an FYI, if the immobilizer light or for that matter the seatbelt warning light is replaced with an LED, the warning light will illuminate. The fix is to put an original incandescent bulb back in its place.
Also, here is a page on sorting out immobilizer issues:
https://993servicerepair.blogspot.co...-lighting.html
Andy

 

I do mean the immobilizer light is flashing.

I have cleared the codes and they immediately come back. After clearing the faults, I then get a message Durametric cannot communicate with the module. Odd...

No other warning lights come on with the CWL.
The (flashing) immobilizer light and CWL started at the same time.
No work done when issue started.
Once the CWL is cleared (using the switch on the central console), it stays off until the next time the car is started.

And, again, there are no observable issues with the immobilizer (or alarm). The car locks, arms, unlocks, and starts without issue.

 

What you have is strange indeed: 3 modules (ACU, IMMO and Central Informer), all reporting "errors" that don't seem to be affecting the car in any way. The other thing that's odd is that when the central warning light goes on, my understanding is it's accompanied by another warning light telling you the specific fault, but all you have is the CWL. These three modules are separate and perform unrelated functions: The ACU monitors anti-theft-related things (doors, radio, glovebox, etc), the CI monitors critical vehicle faults (brake pressure, fuel, airbag, etc) and the IMMO gives permission to start. Hard to come up with one thing that could suddenly (and simultaneously?) affect all of them this way. Each even has a separate chassis ground. the only thing common to all of them is ignition 12v (Terminal 15). Maybe slap a meter on it and see if you see anything unusual?

 

The alarm/door lock control unit does not have a warning light. The Porsche Drive Block immobilizer warning light will not affect the Cental Warning Light. None of the alarm unit fault codes you are listing will affect the operation of the car unless the alarm is activated. (sounding) If the alarm is activated, it will not allow starting.

Something else must activate the Central Warning light. I put my 5 cents on a fault code in the airbag control unit, and that the airbag warning light has been removed to get the car through annual inspection. I have seen that numerous times.
Use the OBD tool to read out fault codes from Engine, ABS and Airbag control units.

I also guess that your Durametric system is incompatible with the alarm/door lock control unit in the way that it does not delete the codes. It is not uncommon to see all these fault codes after disconnecting the battery.
It could also be a faulty Alarm/door lock Control Unit, i have seen such cases where the unit has corrosion damage after water leaks in the car. It is placed on the floor under the passenger seat, and will get wet if the car has a water leak.
Cheers,
Tore

 

Thanks, Jay. To be clear, the immobilizer light does flash when the CWL is on. Once I clear the CWL light with the switch on the center console, it stays off and the immobilizer light continues to flash. For now, at least, I have removed the bulb for the immobilizer warning. I will check the battery voltage. I have a meter which plugs into the cigarette lighter I can use.

Thanks, Tore. Duramteric is not showing any faults in the ABS, Airbag, or Engine modules. Maybe Durametric is not the best scanner for the car. I will see if I can find anyone local with a Hammer or other scanner. Maybe I need the T-OBD?

 

Right, but the immo warning light isn't associated with the CWL at all. The Central Informer has no idea what the immo is doing and has no wire connection to it (other than ignition 12v). I still think that if the CWL were indicating an actual fault, you'd see another warning lamp. Otherwise, what's the point of the CWL? Maybe as Tore suggested, a lamp is burned out. When you clear the ACU flags with the Durametric, do they stay off for a while and then come back, or just never clear?

 

OK, I see what you are saying now. I am not seeing faults with the airbag module, and I have confirmed there is a bulb in the airbag warning indicator location. I have not swapped the bulb out with a known working bulb but will do so. I might have time tomorrow morning to check this out and re-scan and will report back.

I do not think I can clear the ACU flags. When I try to clear them, Durametric seems to get a bit confused and gives me a message it cannot communicate with the module. If I then disconnect the OBD cable and restart the process, and I can access the ACU module and see the flags again. Most likely they are not clearing, but I guess they could also be immediately resetting.

 

The Durametric system is unable to clear the fault codes indeed, all these codes would not appear instantly, and at the exact same time.
You could turn on the ignition and see if any of the warning lights are missing. (almost) All of them should be on at ignition on, before engine start.
Cheers,
Tore

 

Make sure ALL warning lamps are present and good. You could actually have a REAL CI fault but a blown lamp is masking the source.

This might just be Durametric thing and what you're seeing are old, inactive ACU flags that you can't clear, i.e., a "problem" you can probably ignore for the moment.

As far as the immo warning lamp - Porsche gives no guidance in the Owner's manual on the cause of a flashing light, other than "the cause of the failure must be rectified by an authorized Porsche dealer". I'm sure this means selling you a new immo, installing it and programming your FOBs. ($$) I'd just keep an eye on it, especially since the FOBs work and the car starts. Mine has flashed before and stopped on it's own, so who knows......

 

Today one of my SoCal Porsche independents called about a flashing immobilizer light very similar to what's been described in this thread, i.e. a flashing immobilizer light shortly after a key-on.
The immobilizer appears to been serviced, as it had sticker attached from the vendor. I provided my customer an another alarm ECU, per his request. The alarm ECU had no effect in eliminating
the immobilizer flashing.