Hello all, I have scoured the forums for ages now and have not yet found a solution for my problem yet. The center locking system on my 04 X-type 2.5L has not functioned properly since I bought it last February.

I can unlock the car via the remote no issues and all the doors will unlock via the passenger or the driver door handle every time. Also, if I turn the key twice from the driver door to unlock the door, all doors will unlock. No issues with unlocking the vehicle thus far (fingers crossed).

The problem really lies with locking the doors; where locking the doors with the fob doesn't work (the fob fails to lock any of the doors). What's weird is even if the doors are all unlocked and the lock button is pressed on the fob, the car will honk to notify that the vehicle is locked (when it actually isn't). Furthermore, when the latch on the driver or passenger door is set to lock, all the doors will not lock as they are supposed to, only that door will lock. Locking the vehicle from the outside with the key itself also does not lock the doors, only the driver door is locked. Lastly, the drive away locking feature doesn't dork either.

At this point I have been locking all doors individually with all the doors closed and then locking the drivers door last from the outside.

So far, here are my thoughts, I am hoping that someone can provide insight or a different perspective to this problem. I have ruled out the ignition flap that closes when you pull the key out as a suspect because the car should either beep if the flap is open or the drive away feature should work if that was the issue. Also, I am assuming at this point that all the door ajar switches are functioning properly as the car will chirp to confirm that the vehicle is locked (even when its not), and it will double chirp when attempting to lock with any doors open. This should mean that while looking at the electrical diagram, I should be able to rule out all grounds as a suspect? Also, if I manually lock any of the doors and attempt to lock the rest with the fob or the locking latch on the driver's or passenger handle, I should be able to pinpoint the lock that is failing to lock and therefore preventing all the others from locking? So far I have tested all doors systematically and trying to see if locking the door with the fob, the interior door latch or the exterior key hole will result in all the doors locking if i have one pre-locked (no result, the symptoms persist).

This is a very weird issue and I don't know what else I should look at as the culprit anymore. P.S. I did check the linkages on the drivers door to see if they were out of adjustment i.e. to see if they had skipped teeth over time, they had not. I should also say that the issue with not being able to lock the doors used to be intermittent but I could never point at what caused it to work and what didn't but recently it has stopped all together. Attached is the wiring diagram from the electrical guide. Any insight is appreciated. Cheers.

 

Hi Aram,
I don't have this feature, but it sounds like the locking function is definitely being inhibited.
Normally this would be a door ajar, but you would likely have an interior cabin light on and certainly a warning message in the instrument cluster message centre telling you so.
The boot (trunk in the North Americas) also has a open detection switch within the latch assembly which could inhibit general locking from the fob, but I would not think it would inhibit manual locking of all doors.
The bonnet has a switch too (left shock tower vicinity) which doesn't appear in the central locking schematic, so possibly only feeds into the security package for anti-tamper protection.

I would look at the two sensor lines that feed back into the GEM from the driver's door latch (CA86 pins 14&16), namely the ones shown as "Set and Reset" which appear to be momentary contacts to earth. If either is not activating properly or has leakage, it could be confusing the GEM as to the readiness state of the drivers door.

 

Thank you very much Mark, I hadn't looked into that yet, I'll definitely try back probing and seeing if the feedback at those connections are appropriate.
I should've stated in my original post that I have verified proper responses for the bonnet and boot switches. Also, the interior lights do turn off after a while even if the doors are not locked indicating that all the door ajar switches are functioning correctly.
Your reply gives me a lot to go on for now but I should mention that since I made my first post, I tried enabling and disabling the driveway door lock feature by cycling the driver lock latch and this is in fact what led to my center locking working again intermittently. Again the problem persists where I can use the lock button on my key fob to have the car verify that my car is locked (it honks) and when it does so I can hear all of the door locks attempting to lock again but if I attempt to lock all the doors with one or all of the doors unlocked, the car will not lock.
I bought the vehicle as the drive train and the general functionality that I got for the price made it an exceptional deal at the time (not to mention the unique styling that I have wanted since high school) but the center locking problem is a real bummer as its very inconvenient and slightly embarrassing. I appreciate any and all ideas at this point besides mine HAHA.
Thank you.

 

Finally managed to track the fault down. It was actually IP5-5 terminal from the GEM to the circuit that feeds power to all the locks when the driver or passenger door lock is engaged manually. For now all the doors are functional with the use of the physical key or the door handles. I don't know from my limited testing at this point whether just cleaning the connection is gonna be a long term fix but I guess well have to see.

On another note, now that I have a properly functioning central locking system, I need to diagnose why the car seems to refuse the lock button command to lock the doors if they are unlocked but will attempt to lock the doors if they are already locked. When the doors are locked, the horn will sound and the indicators flash confirming that the doors are locked. I have looked through the electrical guide and so far, there is not a lot of information on the remote function. Even the input to the GEM seems to be a basic voltage or a ground input. Please correct me if I am mistaken but I don't see any serial data input for the remote lock and unlock at least.

 

Looking at your diagram.....Double check that the "lock and unlock" switches in the both front doors are actually sending the correct "low" feedback to the GEM, indicating to their physical locked or unlocked status.
If either door is providing the wrong feedback, then the GEM could be confused.
Note: Only the drivers door has the set/reset momentary switch in the door lock being monitored back to the GEM.