QuestionQUESTION: Vehicle: 2001 Cabrio, 72k mi, good condition
In terms of the power door locks and security system, everything works
correctly EXCEPT ... just recently, a change: When I lock the vehicle using the
remote, the light on the driver's side door release immediately starts to blink
but the door locks do not drop for 20-25 seconds and the security system
also does not engage for the same delayed period. Once the door locks drop,
the vehicle is locked and alarmed and the usual chirp and light blink occur. I
have three different remotes and they all behave the same so I have ruled out
the remotes. When I lock the car using the key, the door locks drop
immediately and the security system engages immediately (like you would
expect and like it has always behaved when using the remote). I have a diag
device to read the onboard computer and there are no failure codes
displaying. It's basically usable but the delay is annoying because you are
never quite confident it will lock and alarm unless you stand there and wait
out the 20-25 second delay. In terms of unlocking the vehicle, the remote
works immediately like it always has. Any suggestions for where to look for
the problem?
ANSWER: Hi Joe;
Even though it's a 2001, it's still an A3, so the locks are operated using a separate vacuum pump, and hard plastic lines. Check inside the drivers door hinge area. Remove that accordion thing over the wires. There's a vacuum coupling centrally located after you twist, and separate the lock on the harness connector, and separate the 2 parts. There is also, a little tiny "o"-ring that seals the vacuum passage. Replace it, and see if the wait is shorter. I highly recommend using a little Vaseline to aid in the insertion , and seal of the new o-ring. Good luck.
---------- FOLLOW-UP ----------
QUESTION: I've checked all visible vacuum fittings. There does not appear to be any
leaks. I inspected the vacuum pump in the trunk. It sounds like it is operating
properly in both lock and unlock modes (I can hear it actuate and then a slight
passage of air once the action is complete). The problem almost appears to
be electrical/electronic in that the delay is consistent and only happens when
using the remote and only on the locking action. Again ... I push the lock on
the remote, the light on the driver's side lock button immediately starts to
blink, and then 20-25 seconds later, both door lock buttons drop and the car
is alarmed. If I use the key instead of the remote, the door locks buttons drop
immediately and the car is alarmed. I am assuming that regardless of
whether the doors are locked via the remote or via the key, the actuation is
still by vacuum. Is this a good assumption? Also, can you tell me whether a
single vacuum signal is used for both lock and unlock actions? In other words,
the vacuum pump provides a single source of vacuum to each door and there
is an actuator with a valve at each door lock mechanism that is controlled
electrically that either exerts mechanical motion to lock or unlock. If this is
the case, then leaky vacuum lines should cause slowness in both lock and
unlock modes (I would think). Is it possible the alarm module is faulty and
causing a delayed signal to lock? And how likely is it that this would only
happen via the remote and not via the key? I am mechanically and electrically
inclined. I would appreciate a primer on how the system basically works. I
have a "generic" VW/Cabrio shop manual and it provides no detail on how the
power lock and security system actually work.
AnswerHello, again, Joe;
Thanks for the update, and the additional information, after your inspection. Yes, the vacuum pump is in the trunk, and an "escape of air" is typical pressure/vacuum release at the end of a locking/un-locking cycle.
There is a "black box" responsible for control of the alarm, electric windows, door latch communication, interior lighting, and remote features. It is the "comfort/convenience module." This device is located under the dashboard, above, and very slightly to the left of the main relay panel. It takes the space of between 2, and 4 standard size relay "boxes." It will have an "engineering" number silk screened on to it, in white paint. There is a way to communicate with, and test the device, but this requires a VAS scan tool, or VAGCOM, and laptop, and a working knowledge of "value measuring blocks." If you can get a VAS, or VAGCOM, the address word to select is "46...comfort module." On an A3(which is what your car is)one would normally look at address word "35...central locking." However, since your car is a 2001, I think the comfort module is in control, and only if your car had manual windows would there be a central locking module in an A4, and all(?) 2001 model Volkswagens shared these features...otherwise certain fault finding techniques, and programs wouldn't work on all(?) vehicles.
At any rate, once you are into "46, or 35," you then need to go to "value measuring blocks." Blocks 0 through 10 concern the entire system, as it relates to the alarm/locks, and the remote controls' ability to interact with the system. Don't go to value block zero(0), otherwise ALL of the remotes for this car will be removed from the memory, and the memory will require reprogramming...or "adaption." If you start with 1, and go to each subsequent value, 1 at a time, you can begin to build a "roadmap" of the values. I think this system will take an input value up to 258 or so. It may take several hours to build your map by going one at a time, and not all of the "blocks" will be self-explanatory. I am not aware of any forum that makes this information available, so it will be up to you to gather what you can in this exercise, and then IF there are say 5, or 6 blocks that look promising, and may help you repair this car, contact me again through this website, and I will attempt, and I would like to emphasize, ATTEMPT to gather the information on those values for you, but I can't guarantee I will be able to, only because my access is limited, tracked, and recorded, and then reviewed by my foreman, manager, and technical support staff at VW of America, so I might not be ale to get the information you need in a timely manner, or at all, until I get a Cabrio to work on. I'm not trying to duck your issue, it's just that I need to review these measuring blocks, because models vary, and I don't have all this stuff memorized. I know where to start my investigation, and I've shared that with you, but once into a repair strategy, I am guided by proprietary software, and technical support. So, ultimately there may be some small bit of information you need to fully diagnose that module, and neither of us will know it, at least not in advance. I'm just saying I'll help within the realm of my limits. Unfortunately, those limits are not all self imposed. Let me know if you are able to get some measuring block values, and what the channels within those are....there should be 4 channels in each, but not all 4 are always used...sometimes 1, sometimes 3, etc. For example, in value measuring block 1, at address word 46(comfort), there is only 1 channel, because this is the recorded memory of how many remotes there are for your car. Most have 2 remotes, but you can have up to 8 remotes for the same car. However, there is only a need for 1 "channel" because there will only be 1 applicable value for that car. Got it?
The only reason I brought all this up is so you don't go out, and waste money on a new part. You can't buy a new part with 100% assurance that it will operate in your car anyway. You need a VAS tool, or a VAGCOM, and laptop just to get the correct part number, AND "coding," for your application. Not only that "coding" isn't called coding for this part, it's called, "color." So, if you decided to just pull out the comfort module in your car, and replace it with a new one from the dealer, they couldn't order it without part number, AND "color." I hope you get closer to the solution with this information. Good luck, Joe.
