996 Turbo central locking issue

I have a Porsche 996 2001 US model, that will not central lock, and the symptom is an immediate unlocking after attempting to lock. Durametric reports the following errors: Alarm i32 1: Door secured and terminal 15 on 43: Alarm actuation by passenger's door. 44: Alarm actuation by driver's door 61: Central locking limit position Unlock not reached Alarm i48 1: Door(s) secured and terminal 15 on 43: 61: The red central lock button on the dashboard also lights red. To attempt to fix the problem, I have: Inspected the M535 for any sign of water damage/corrosion - which it does not have it. Cleared all faults using the Durametric. They immediately reappear when I attempt to lock. Replaced both actuators. I can hear the motors engaging (on both the new and old actuators) when I attempt to lock, so the activation and mechanics seems fine. Done continuity testing on all micro-switches, and they seem ok. Done continuity testing from the passenger side A pillar to the M535 (pin 7, 28 and 32) Done continuity testing from the drivers side A pillar to the M535 (pin 5, 25 and 30). Tested resistance between what I presume are the relevant pins and ground, to check if I have a short, which I don't seem to have. Measured the current in the M535 -> doors for the respective signals. To do this I found the wires on the M535 that should be related to latch, lock and secure for both doors and stripped off a small piece of isolation and used a multi-meter to measure current while using a Durametric to trigger these actions. I had high hopes for this approach, but it was not conclusive. Latch gave a reasonable result. Either 0 or 12V, but lock and secure seemed to stay around 6V which I find strange. Especially since I can hear the respective engines engaging. This is incredibly frustrating, and I have no idea on how to progress, so feedback is much appreciated. Here is a the M535 wiring diagram that I created for debugging. Maybe someone finds it useful Pin Color Function Expected State / Notes ------------------------------------------------------------------------------------------------ I / 1 GR Antenna RF signal V / 2 1.5 BK/YE Alarm Horn Output V / 3 0.75 BL/YE CL Motor Close/Open Pulse output V / 4 0.35 BK Control Signal Transformer Signal V / 5 0.35 BL/RE Door Safe Driver's Side Ground-switched status V / 6 0.75 BK/WT Turn Signals Left Pulse output V / 7 0.35 BR/GN Door Contact Passenger's Side Ground when open V / 8 0.35 GR/WT Interior Protection Data Send Data V / 9 0.75 GN/RE Locking Motor Close Pulse output V / 10 0.5 BL/GN/RE Drive Motor Tank Cover Open Pulse output V / 11 0.5 BR/YE Inside Light Switched ground V / 12 0.75 BK/GN Turn Signals Right Pulse output V / 13 0.35 BR/RE/BK Cover Rear Ground/status input V / 14 0.35 GR/PK Speed Sensor Signal V / 15 0.35 BR/RE Unprime Door Signal I / 16 0.35 OR Terminal 86S Key-in-ignition sense V / 17 0.5 RE/BL/BR Luggage Compartment Light Rear Switched output / status V / 18 0.5 BR/GN/BK PW Control Signal V / 19 0.5 BL/BR Safe Motor Close Pulse output V / 20 � Not shown on this sheet � V / 21 � Not shown on this sheet � V / 22 � Screen Antenna GND Ground / shield V / 23 0.35 OR/WT "W" Lead Signal V / 24 0.35 GR/BL Interior Protection Data Receive Data V / 25 0.35 BR/GN/WT Door Contact Driver's Side Ground when open V / 26 0.35 BR/OR Package Tray Ground/status input V / 27 0.35 BR/VI Radio Contact Ground/status input V / 28 0.35 BL/RE/BK Door Safe Passenger's Side Ground-switched status I / 29 0.35 BR/BL/RE CLS Button Close Signal V / 30 0.35 BL/WT/BR Door Locked Driver's Side Status V / 31 0.35 YE/BR Cover Front Ground/status input V / 32 0.35 BL/WT Door Locked Passenger's Side Status V / 33 0.35 GN/OR Crash Input Signal V / 34 � Not shown on this sheet � V / 35 0.35 BR/WT Door Lock Cylinder Close Signal I / 36 0.5 BK/BR Terminal 15 IN 12 V with ignition ON V / 37 0.5 RE/YE/BR Luggage Compartment Light Front Switched output / status V / 38 0.35 GR External Electronic Signal V / 39 0.35 GN/BK Functions Indicator Signal V / 40 0.35 YE/BL/RE Comfort Open (Cabrio) 0.35 YE/GR Comfort Open (Coupe) Signal I / 41 0.35 WT Door Locked Display Output V / 42 0.35 YE/GR/BL Comfort Close (Cabrio) 0.35 YE/GR Comfort Close (Coupe) Signal V / 43 � Not shown on this sheet � ------------------------------------ Central lock relevant M535 pins: Ds V / 5 0.35 BL/RE Door Safe Driver's Side Ground-switched status Ps V / 28 0.35 BL/RE/BK Door Safe Passenger's Side Ground-switched status Dc V / 25 0.35 BR/GN/WT Door Contact Driver's Side LATCHED Pc V / 7 0.35 BR/GN Door Contact Passenger's Side LATCHED Dl V / 30 0.35 BL/WT/BR Door Locked Driver's Side Status Pl V / 32 0.35 BL/WT Door Locked Passenger's Side Status ------------------------------------

I had a very similar problem with the car unlocking after locking it. The button that is opening the front hood was stuck. After that everything returned to normal.

I have actually tried removing it, but it made no difference. Thanks for the feedback though! Very frustrating issue.

Can�t profess to know much about alarm modules, but 996 owners have fixed the central locking anomaly by taking their alarm modules or entire car to Porsche classics center to have the modules reprogrammed. Hope that helps.

Spent 4 months working through locking issues. About $800 to ecudoctors in FL for them to reflow the board fixed it. They will do a $99 diagnostic to verufy correct operation.

I went to a Porsche Classics center in Norway, and they did some diagnosis, tightened the bolts on my battery and charged me ~ 400$. They told me that it's "most likely the actuators", which I told them that I had already replaced, so that seems unlikely..

Quotes source post: 20578713

I wish I count do the same, but I am located in Norway.

If i remember correctly there was company doing the same in the UK. Dont know how the whole eu thing works? U may be able to ship to the usa for repair? Maybe contact them? https://www.ecudoctors.com/

Quotes source post: 20579202

Yeah, there's these guys in the UK. https://www.jmgporsche.co.uk/index.php/itemlist/tag/key

And these guys: https://ecu.de/porsche-56

I tried a few more things to diagnose the issue: * disconnected the cable to the driver door by the A-pillar, and ran i32 and i48 tests. All the same alarm codes re-appeared after clearing. * disconnected the cable to the passenger door by the A-pillar, and ran i32 and i48 tests. All the same alarm codes re-appeared after clearing. So, I still don't know if the issue is related to one door, or the M535. Sheet 8A here describes the alarm unit: https://www.rennkit.com/wp-content/u...iring_2002.pdf CLS Alarm System What I noticed is that if I lock the doors using my Durametric, I measure the following: Pin 30 (A30 DOOR LOCKED DRIVER'S SIDE), I measure 13V when locked, 0V when unlocked. Pin 28 (A32 DOOR LOCKED PASSENGER), I measure 5V when locked, 0V when unlocked. This is the only asymmetry that I have detected, so it might be an issue with the passenger door?

I just measured pin 32 by the A pillar male door connector on both the drive- and passenger side. The passenger side measured ~ 5V and the driver side measured ~ 12V. So, I guess the problem is some car-internal wiring, and not a problem within any of the doors?

U need to disco the A piller plug, back pin the connector on the immobilizer and see if the immo is outputting the correct voltage

Thanks, I have measured: 6.5V at the immobilizer with the a-pillar connector connected (just by removing some isolation from the wire). 6.5V at the a-pillar with the connector disconnected. My conclusion is therefore that it must be either: Dashboard short-to-ground. Internal M535 Failure I will try 1 (just measure resistance between the connector and chassis ground?) first since I'll have to cut the wire to the immobilizer to test the voltage at the M535.

Although my central locking system, immobilizer and frunk / engine bay buttons and latches work (for now), I would ditch them in a heartbeat for a simple door lock / ignition key along levers with cables for the frunk and engine bay. 996.2 coupe. No one’s going to steal it.

I am more concerned about things that I leave in the car, and I am only able to lock the drivers side with the key... I did yet-an-other-test, and measured resistance between pin 32 in the a-pillar connector and ground, to check if it was a short. It wasn't. So, I am fairly sure that I only get ~ 6.5V out from the M535 to the passenger door (in contrast to 12V on the drivers door), so my only guess is that e.g a pull-up or something in the M535 is broken?

I cut 30 and 32 by the immobilizer, and measure ~3.5V on both. WTF?