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Discussion Starter · #1 ·
Hi

I own a 2003 Passat wagon and for the last few months the trunk lid has not been able to lock itself, it closes fully but it just wont lock. So I decided to go ahead and change the lock actuator and the lock motor and even went on to replace the hatch as well. I did not know which of those caused the issue but I decided not to take any chances.

Anyways

After replacing these parts I now can't lock the car or unlock it at all, I press the keys on the fob but nothing happens. The trunk lid is now permanently locked unless I open it from the inside pulling the emergency lever. I have checked all the fuses, all were okay. I noticed that the clock as been reset as well the trip meter... this is very strange, perhaps I short circuit something?

I should also mention that the drivers door and the left rear door has been intermittent for a few weeks as well, sometimes I have to press unlock on the fob twice for the alarm to go off before I can open any doors.

So I'm guessing the CCM is at fault here? or the entire Central locking system?

Any help is much appreciated!
 

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First, I would try syncing your FOB with the car.

If I recall:
put key into ignition,
turn on (but do not start car),
hold unlock while the key is in the ignition for 5 seconds or so
turn off, remove key, try fob.
Do this with the second fob as well.

Are your plenum drains clear?
your carpet/padding by the dead pedal dry or wet?

When my 02 GLX wagon had a tailgate NOT unlocking electronically issue, was the lock actuator. 5 bucks from the salvage yard. PITA to remove and replace, but didn't take too long.
 

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After replacing these parts I now can't lock the car or unlock it at all, I press the keys on the fob but nothing happens. The trunk lid is now permanently locked unless I open it from the inside pulling the emergency lever.
Can you lock/unlock with the key in the driver's door?
With the lock/unlock buttons on the doors?

Can you release the trunk with the switch on the driver's door, or do you have to crawl in the trunk and use the manual release there?

Do your dome lights work? (They're powered from the CCM, fuse 14, I believe)
 

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Discussion Starter · #4 ·
First, I would try syncing your FOB with the car.

If I recall:
put key into ignition,
turn on (but do not start car),
hold unlock while the key is in the ignition for 5 seconds or so
turn off, remove key, try fob.
Do this with the second fob as well.

Are your plenum drains clear?
your carpet/padding by the dead pedal dry or wet?

When my 02 GLX wagon had a tailgate NOT unlocking electronically issue, was the lock actuator. 5 bucks from the salvage yard. PITA to remove and replace, but didn't take too long.
No luck with syncing the fobs, the plenum drains looks clear and no signs of the carpet being wet at all by the dead pedal, however I have noticed a lot of water resting on the drivers door sill, don't know if that's normal or not.
 

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Discussion Starter · #5 ·
Can you lock/unlock with the key in the driver's door?
With the lock/unlock buttons on the doors?

Can you release the trunk with the switch on the driver's door, or do you have to crawl in the trunk and use the manual release there?

Do your dome lights work? (They're powered from the CCM, fuse 14, I believe)
I can not lock/unlock with the key in the drivers door. But I can lock/unlock with buttons on the drivers door yes.
I did not notice until now but the domes lights are not working at all. Checked fuse 14 and its fine.
 

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It appears that you have wired the trunk lid incorrectly.
Check for short, to ground or another wire.
Check that all wires are connected to the right places.
Any of these could cause all of the new problems you have.

Unless the key is turning more than 90 degrees in the door, I expect it would function correctly.
Note: It takes a bit more force on the key in the door, if the central locking system is not working.
 

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After you get the trunk lid problem corrected, you might like to address the old problems.
Seems like there is water leaking in under the carpet, this is likely coming from from the door.
Ensure that the inner (metal) panel is properly sealed and not leaking. (There can be a lot of water under the carpet before you notice any dampness on the surface)
Do a scan of the CCM and post the Codes.

It looks like you have a problem with the floor harnesses or grounds or the CCM, you can get this fault with or without water ingress.
Locate and fix source of water ingress, if any.
I suggest you completely unwrap all of the CCM harness and pull the wires apart to find the splices, any corroded splices need
to be cut back, soldered, and covered with marine grade heat shrink tubing. (You might need to add short wires to replace what you cut out)
Also check ground connections (1 on floor and on "A" Pillar), and check CCM/TCM and "A" Pillar connectors.

Have a good look at this link, before you start.

This thread attempts to bring together all the problems regarding water ingress and their solutions.
Water Ingress and Solutions
 

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Discussion Starter · #8 ·
Thank you all guys for your replies, much appreciated! I will look deeper into these problems/solutions and try to fix it. Hopefully these ideas will narrow down my problem quite a bit.

I shall report back once I've uncovered the CCM and it's wires.
 

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Discussion Starter · #10 ·
You should fix the trunk lid first. Or you won't be able to do a scan.
I have tried my best to fix the trunk lid in anyway I can, I have checked the cable connections dozen of times, everything is connected and in place. I just don't know what else to do. I did forgot to mention after installing all the stuff I pressed the trunk hatch, and i noticed something, the number plate lights came on, I heard a noise from the latch engine and the clock and the trip meter got reset. After that nothing worked at all, fob key, windows, no radio signal, dome lights etc.

Anyways after lifting the carpet to uncover the CCM box I noticed this ground cable, you can see the pictures that it is indeed very corroded. What do you guys say about this ground cable? Would it be functional with this much corrosion? Is this my problem? I have yet to check the A pillar.

Photography Soil Floor Metal


No sign of water ingress or leak at all. Everything was really dry, carpet showed no signs of water damage or mold, the box was like new, it even smelled new when I opened it.
So signs of spliced or bad cables except this ground one.

I tried to scan with my aftermarket OBD-II scanner. It seems I cant scan the CCM at all. I get a "Cant communicate" message.

Few other things to mention:

The alarm indicator lamp flashes rapidly at some point. I think it was when i pulled out the alarm fuse and put it back in.

I have heard clicking noises coming from the fuse box back a few weeks prior to this.

The function to roll/up the windows from outside the car by turning the lock from drivers door stopped working ages ago (more than 10 years ago probably) is that CCM related?
 

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I have tried my best to fix the trunk lid in anyway I can, I have checked the cable connections dozen of times, everything is connected and in place. I just don't know what else to do. I did forgot to mention after installing all the stuff I pressed the trunk hatch, and i noticed something, the number plate lights came on, I heard a noise from the latch engine and the clock and the trip meter got reset. After that nothing worked at all, fob key, windows, no radio signal, dome lights etc.
It appears that you have some of the trunk lid wiring incorrect. Maybe a wire that should go to the lock motor connected to the NP lights. You need to carefully check all wiring in the trunk lid, and match wire colours to their correct locations.
Then check fuses #6, #14, & #38.
While this situation exists, you will not be able to scan or fix the CCM problems.
 

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Anyways after lifting the carpet to uncover the CCM box I noticed this ground cable, you can see the pictures that it is indeed very corroded. What do you guys say about this ground cable? Would it be functional with this much corrosion? Is this my problem? I have yet to check the A pillar.

No sign of water ingress or leak at all. Everything was really dry, carpet showed no signs of water damage or mold, the box was like new, it even smelled new when I opened it.
So signs of spliced or bad cables except this ground one.

I tried to scan with my aftermarket OBD-II scanner. It seems I cant scan the CCM at all. I get a "Cant communicate" message.
In post #9, I told you that you would not be able to scan the CCM.

After you get the boot lid sorted, do the following:
The ground might be part of the problem.
That ground connection must be completely dismantled, thoroughly cleaned, and reassembled with dielectric grease.
There has been water ingress. There are splices in the CCM wiring harness, you need to find and check them.
You should check the CCM PCB for corrosion and cracks, also check the pins in the connectors.
Then scan and post the codes.

Note: The incorrect wiring might have damaged something.

I suggest you disconnect the battery NOW, and leave it disconnected until you have completed the instructions in the post above and this post.
 
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