ECU Doctors

Yes, what ditto says AND I ask you this because it is not 100% clear to me if you've mentioned/tested it:

-are both the interior door handles fully returning to their position when after you pull on them? They have a spring that tens to stretch and prevents them to return to their position. (I had a similar problem in my Boxster)

-the no communication problem to the alarm system bothers me because it makes no sense.

Can you scan all the other modules in the car. Maybe we'll find a hint as to why you can't access the Immo.

cwilt

Bal,

I will print these out and look at when I get a chance. Taking off for the evening but I had a thought glancing over the schematic.

This sounds crazy but it has happened in the past on more than one occasion. Flaky interior light bulbs that caused very strange electrical problems. I know it's not much to go on but worth a look while you're tracking this problem down.

I will be back in touch when I read up on the circuitry.

bal

cwilt - I'll PM you and exchange email addresses, then can send you a larger version for easier printing. And thanks.

ocfservice

Can you hear the ignition lock when you remove the key? Maybe car thinks key is still in ignition... Steering locks are more than common for 996/986. After replacing lock, if bad, a vehicle handover must be performed to reset car!!!
Window slightly decend when door closed and inner handle pulled both sides??

bal

Progress:
Ditto's post about the front latch (bonnet/hood/frunk) made me think that this is the only real variable since I open and close it to plug and unplug the battery. So, I messed around with it. What I found is that if the bonnet is opened by pressing the fob, I am able to lock and unlock the car with the fob. I get a single beep but that might be due to the aftermarket radio not having the alarm contact, or perhaps because the car thinks that the bonnet is open. When I close the bonnet and hear it latch, I get the double beep when I use the fob and am unable to lock and unlock the car. So... seems like there's an issue with the bonnet latch, which was replaced a year or so ago. You can see the behavior in this video:
Since my mechanic installed the latch, I'll go back to him since it might be under warranty.

I'll keep this thread updated and thanks to everyone for contributing so far!

ECU Doctors

That's a well made video of your issue!

Since your bonnet was replaced, can you check if the connector of the contact is connected inverted.

Seems like the Alarm Immobilizer thinks the front truck is opened when it is actually closed.

bal

Thanks ECU Doctors.

Yes I will check your suggestion. Only the latch was replaced since I'm told that the solenoids go over time and it wasn't releasing. The issue manifested itself sometime after the latch was released though and not immediately after. I did notice last summer on hot days that the latch would not release, which makes me think that it may just need adjusting and something is shorting out, and perhaps it is an intermittent short which is causing the alarm system to think that something it is amiss. Anyway, lots of speculation at my end until I actually get a chance to look at the part and the connections. Once I have access to the connector from the car, I can try bridging it to simulate open and closed positions and see what the alarm module thinks.

bal

Another update... push down on the bonnet but do not let it latch, locking and unlocking works normally. If I push down further and let it latch, I get the double beep. If the bonnet is latched and I try to pry it up a little, I still get the double beep. Together with the latch not operating when it is hot, all this leads me to believe that the latch may need to be adjusted so that it sits higher. Perhaps the double beep is caused by some kind of short between the microswitch and solenoid. Again, I should be able to see more once I have access to it. But first, I await the delivery of the parts I need to repair my driver seatbelt-related airbag error *sigh*.

bal

Also, I meant to reply to ECU Doctors' comment about the comms problem between Durametric and the alarm system. I should have been more explicit: Durametric sees all the modules including the alarm system and is able to erase alarm system codes. What I cannot do is to perform any of the activations on its Activation screen (door lock, door secure, interior light, etc.) I've not tried this since my last two updates though.

bal

Well one step forward and several back...

I took the bonnet/hood latch off to inspect it. I've verified that I get an open circuit when the latch is closed, i.e. the hood would be shut, by pressing the shaft of a screwdriver through the mechanism to simulate the metal U attached to the hood. When I release the latch, i.e. the hood would be open, I get continuity.

I tried the keyfob with the latch removed, so the car would think that the hood is shut, and I get the double beep and no locking. If I jumper the plug that connects to the latch, so the car thinks that the hood is open, I get a single beep and it locks fine. With the plug jumpered, the trunk compartment light is on, as I would expect.

From all of this, I think that the latch behavior is correct, which now makes me suspect the alarm control module *sigh*. I suppose I could remove the compartment bulb and jumper the plug and get the locking through the remote, or live with no locking through the remote and just use the key in the door to lock and unlock.

ECU Doctors

From reading your last post I wonder if you could invert the connector so that the behavior is the opposite.

It seems like that would solve your problem

bal

You'd mentioned this earlier and I forgot to respond to that point. The connector is keyed, so it is currently connected with the correct orientation. I did not try reversing it because I would need modify the connector to do so, however, referring to the schematic, it is simply a switch so reversing it should have no effect. I've also spent some time reading the WSM about the alarm system and have learned that it is quite a complex beast with various modes of operation. By jumpering the hood switch and removing the compartment light, I may cause unintentional side effects.

I think my next step is to see if I can convince my mechanic to let me spend an afternoon with his PST2 and start to look at various signals, which I'm unable to do with the Durametric.

bal

I replaced the solenoid, but there's no change in behavior: no double beep with the hood latch microswitch "closed" (i.e. the hood is open), and a double beep and no central locking with the hood latch microswitch "open" (i.e. the hood is closed).

An interesting discovery was that the 6.5.3.5 version of Durametric that I upgraded to last week had a bug that prevented certain codes from being cleared. They released 6.5.3.6 on 5/3/17 that addresses these bugs, so I was able to clear the alarm codes. What persistently comes back is Code 60 - Central locking limit position Lock not reached. I have been through all the troubleshooting steps in the WSM for this code and everything checks out. I do intend to verify the interior and exterior door handle microswitches and see if I can spend some time with my mechanic's PST2 to troubleshoot further and remove the Durametric variable. However, my guess is that I'm dealing with something wrong in the alarm control module. The reason I am leaning towards this conclusion is that previously, I've been able to trigger Activations from Durametric but these no longer seem to work (although perhaps this is another Durametric bug), and also Durametric has consistently reported the radio contact not being present, which it no longer does.

If someone has access to the WSM and feels like sending me the troubleshooting steps for Code 60, I would appreciate it. It is possible that they've been updated since the version that I have access to. It is in Group 0 Section 90.

Incidentally, while preparing for power on tests, I managed to close the hood with the battery disconnected. Normally, the release cable is behind the tow hook plug on my car, however, when I was working on the hood latch earlier, I must have moved it since it wasn't there! I was able to open the hood by applying power from a jump starting unit to the positive terminal in the fuse holder in the driver's side footwell (LHD), using the door arrester. Fortunately, this works even with the negative terminal of the battery disconnected!

bal

With everything but together and driving around with the top down today, I noticed the locking was working correctly. Both the hood and trunk latches were closed so the only thing open was the top. I pushed the microswitch on the latch for the top and sure enough, the central locking switch came on and the double beep/no central locking manifested itself again when I used the key fob. I popped the trunk latch, pushed the convertible top microswitch and with the trunk latch open, no double beep. With the engine running, the top down, both hood and trunk closed, I got out and tested the doors. I leaned against each door to prevent it from opening and used the exterior and interior handles to "open" the doors - what I was really doing was activating the exterior and interior handle microswitches. I pushed the convertible top microswitch and only then did I get the locking failure. Tried the same thing with the glove box and storage compartment. It seems like the only time the central locking works correctly is when the hood, trunk or convertible top are open. Weird.

cwilt

That is very strange. Seems like a circuit is reversed or thinks its reversed. Did you get a chance to hook up a PST2? I think that might be the next thing since this is so weird.