I have 04 CTT and have been experiencing weird thing with the car. When the weather is hot the passenger door driver side won't lock whether I use the key or the key fob. I know it b/c the locking mechanism will not make sound and I try to open the door. It will open and the alarm goes off. When the weather is cold it will lock.
I did try to use WD 40 spray into the door lock but it still does not work. Have anyone experienced this? Thanks guys.
BTW, I did search the forum but did not see any links or info about this issue.

ALX5

 

Another things I found out today are: when I used the key fob to unlock it made clicking sound but not when I tried to lock it. the light in the door does not blink when I unlock it. the other doors lights do blink when unlock.
ALX5

 

Had the same issue on the rear doors of my 04 CTT. On mine, the actuator mechanism stopped working. Replaced the entire door lock assembly with ones from an 06.

 

I seem to have this exact problem on my 2004 S.

I have searched pretty thoroughly on this forum and everywhere, but no solid answers. Just a few people with the same problem.

More details for my case:

2004 Cayenne S, 102k miles, no other problems, no recent work in that area
Everything was working fine, then about a week ago, the left rear door would sometimes not lock when all doors were locked using the key fob. Doing it again would always eventually be successful, until yesterday ...

Now the left rear door will not lock at all.

All these fail: key fob, driver's door button, left rear door button, all of the above with engine running to make sure I've got good voltage.

Door opens / closes just fine. All other doors are fine in every way.

Unlocking is fine (I can hear a click/clunk in there as if it tries to unlock, but since it was not locked to begin with, it does not have to actually do anything). Window operation is fine from left rear door, and from driver's door.

I did NOT yet try to see if the auto-lock, once you start driving above a certain speed, is successful in locking.

Based on the above, I figured there is a problem with the door lock actuator. Figured I'd just pop open the door, do a few easy tests and fix/replace as needed. No problem expected. Wrong.

I got the door panel off pretty easily, and see there is a steel inner shell that seems to need removal.
I removed the 4 T45? screws in the front and rear door jamb areas to mostly free it up.
Removed the M8 XZN triple-square screws holding the striker plate.
Now I'm at the point where it seems the whole glass assembly, rails, inner steel covering, etc. will lift out as one unit. It's very loose, but it seems I need to disconnect some wires, maybe some other things.

So this all seems just a little too much to get to the door lock actuator, and since I can't find any instructions on how to do it (usually that means it is too easy to bother writing down), I thought I would ask before taking it fully apart.

Am I on the right track?

Any instructions anywhere on how to do this (NOT for the inner door panel - that appears pretty trivial and obvious compared to this; Pelican has a nice easy tutorial on that, but nothing beyond it that I can see)? I can't believe I'm the first one to do this.

Is there any way to manually lock the door when I've got this failure mode? Like a hole to stick a screwdriver through and turn a **** or something?

Electrical debugging clues - like testing at the wire harnesses, applying voltage, measuring resistance, etc.? I really did not expect this disassembly to be difficult, so I figured I'd just take it all apart and debug it at the door lock actuator assembly. But now ...

EDIT - I just remembered another clue ... I think when I first got the truck, sometimes the driver's door LED would not flash after locking things with the key fob. Just the right front door's LED would flash. I did not notice any other problems (like this locking issue). But then, that LED issue seemed to fix itself, and now seems fine. Could be completely unrelated.

 

Making progress. To answer some of my own questions:
Yes, you're doing great. Keep going.

After searching through my zillion-page service manual a little more, I found some useful info. Comments on that: The assembly that contains the inner steel door, window regulator, window, and window frame is called the "door unit carrier." Pretty interesting design. I bet it makes for easy assembly and reliability, but at the expense of difficulty in repair.

Searching through the manual is a little difficult because they seemed to make it mostly reliant on drawings rather than words. Maybe so it would work well for people who can't read the language it is in? Anyway, interesting, takes a little getting used to. I can see this fitting in with a software system that does all the actual thinking and diagnosis and just tells the tech to do certain procedures, replace certain items, and then this manual shows them exactly how to do that. Again, different than manuals I'm used to.

YES!!! If I had known this, I would have waited until it was more convenient to do this whole job.

If you look on the painted steel door surface facing the inside of the car, back by the lock, you'll see a little **** for the child lock. Very close to that is a rubber cover thing with an icon of a lock on it. Pull that off, and the orange plastic below it can be manually moved to lock the door. Move that orange thing, then close the door and it will be locked.

The wiring diagrams for the truck are literally more complex than for the Space Shuttle. Analyzing things basically just pointed me to the likely two pins to actuate the lock (#1 and 2 for the 7-pin connector going to the actuator assembly). I confirmed that triggering those pins with plus and then minus voltage will very nicely and reliably open and close the lock, powered with an old 9V battery. So after all that, I'm pretty certain the actuator and lock mechanism are good ... although maybe there is a sensor on some of those other pins that is faulty, so I'll look again.

EDIT - after more thorough testing, I think I've concluded that the door lock actuator is the problem, and was not completely fixed through careful reflowing of solder joints and careful application of JBWeld, So a new one is on order. Until then, I plan to use the manual locking feature if needed.

 

Wow what an ordeal. I have a 2009 Cayenne. When I lock the doors either with key or key fob the emergency flashers come on.. Help please..

 

Hi, I have a 2003 Cayenne S with a very similar problem with the right rear door - it intermittently (at first, now regularly) won't lock when I lock the car. It's the same with internal keylock button or with the remote key. I took the inner door skin off, looking for something loose, and found out about the door unit carrier... got distracted, so drove around without the inner door skin for a few days... and behold, the problem was gone! Worked perfectly every time. So I put the door skin back, thinking it's all good... to find out that the problem's back! So took the door skin off the second time... and all's good again. Had a real think about the issue, and have taken the inner door handle opener off to find it has a sensor on it. It releases the lock to unlock the door when someone pulls the handle on the inside. So I started to wonder if the sensor were faulty then it might be that the lock actuator wasn't the problem, but that it was being inhibited from locking.
I took the sensor out to test it, thinking it was a simple microswitch... and found that it's actually an optical sensor, which I think responds to the movement of the handle past it to activate? Never seen a sensor like it before. Any help would be greatly appreciated. I can attach a photo of the optical sensor if that helps, but don't know yet how to attach it to this post (I'm new here).

 

i have a similar problem, and have worked on a few things. maybe we can work out a solution together.

does your gear shifter or volume **** light stay on when you leave the cayenne off/parked?

when you open your back right door...does the red light “under” the door turn on? you’ll see what I mean if you open the door and look down.

and the window control at that door works okay?

can you include some pictures of your back door before you put the cover back? and this sensor you were talking about?

adding a photo is very easy. hit reply to this comment. just under the word “Message:” you will see options to B (bold) I (italicize) U (underline) the things you write. right next to the icon of a paperclip...click on the little picture of mountain landscape. the app will then ask u to fibd the photo on your phone/computer.

 

Did you find any answer about this problem,i have the ecxatly problem

 

The problem is almost certainly due to an electromechanical fault in the door lock actuator mechanism. Your options are to remove the mechanism and either a) replace it or b) attempt to fix it. There are a number of microswitches and other parts that could be faulty in the door lock mechanism. Removing the door lock is not trivial as the door frame assembly must be removed from the door shell. I have repaired two of the door locks on my Cayenne and each time I have replaced them with new assemblies. Although I am pretty handy with electronics, I did not want to risk having the door apart and not being able to fix the problem or have to wait on parts. It just wasn't worth having the car down for a week or doing the job twice. My advice is to replace the door lock actuator mechanism.

And BTW don't use WD40 in door locks or anything else that you want to keep lubricated. WD40 is a solvent, not a lubricant.

 

There are a few options when you go to buy your replacement door lock actuator. Here is the dealership part next to the $25 Amazon one. Huge difference, many folks have noted that the "feel" of the door handle is cheap if you go with the cheaper replacement part.

This job took me about 7 hours to complete but then I had to tear it all back down again because the window had jumped out of the rubber guide. Good luck.

Dealership replacement part on the right, Amazon cheap part on the left.