Gary-A3

Smart idea. I fixed my driver's door wire loom twice, the last time being about 4~5 years ago. It's curious... only 3 wires had frayed, and one had separated completely. The other wires appeared OK, although I could tell the wire insulation was getting a bit stiff. When that fix I made worked, I then checked the other wires for where they tend to bend and reinforced them with a little electrical tape in hoping of "holding off" the future insulation cracking. The left side doors of my A3 are the most heavily used (USA spec)... and so I suspect that's why the doors on the right have been fine--not getting flexed much. It does make me wonder if that's a time-bomb, though. With rather minimal flexing, perhaps the insulation will further stiffen and then tend to break suddenly at some point (rather than a few filaments broken, weakening voltage across the wires and creating intermittent behavior). Did you inspect the wire looms of the other doors on your A3? They all look perfectly fine and feel reasonably flexible?

Do you know how long ago your friend remapped the ECU for Stage 1? And how long was it from then until this weird sound started to manifest? Because if there wasn't very much time... it might be worth mapping back to stock. Just for peace of mind to eliminate that as a potential culprit. If it has been a good long while, like at least a few weeks... then highly likely the Stage 1 has no bearing on this.

Well, with shipping it ends up being about $10 USD. I figured it's worth ordering just to check out. If anything, I could release the wires and use them with the OEM plug (which is still in great shape).

Yes, I am aware of that (from the first time I had to troubleshoot issues cropping up due to the wire loom insulation cracks on the driver's door). It appears that wherever Audi sourced the wiring, substandard wire insulation was used that unfortunately doesn't turn up with problems until quite a few years past the warranty expiring. I hope Audi corrected this glaring flaw and uses insulation for wiring that's far more resilient and will last far longer. It took me a good while, but I did finally find a video where someone demonstrated the release of the plug from the socket. There's a black tab on the back side of the plug that's pretty much impossible to video capture while inserted. By intuition, I expected the purple portion of the plug was some kind of release tab... and it's not. Anyway, given how this is the second time I'm having wire loom issues, I'm thinking I should buy that loom repair "kit." There's examples of it costing over £55 that comes with the loom segment, pre-stripped, with crimp connectors and a wire sleeve. But I've found on AliExpress.US a version that's just the wire loom segment, pre-stripped, and nothing else. All good, as I have some wire crimps on hand. Does this look legitimate to you? Prewired Door Repair Kit Harness Loom for A2 A3 A4 A6 TT.

Well, "Stage 1" means modifications... and who knows what your friend has also done that isn't disclosed. Looks like he's best off taking it to a reputable shop for a proper diagnosis. Spit-balling the issue on forums is going to turn up a lot of scattershot guesses and will likely not be fruitful.

OK. I understand you're relaying all this for a friend. It makes it a bit harder to do. I don't know if the increased sound is just the natural progression of something failing on the car, or if the work done just helped make it seem more apparent (such as eliminating water pump noise). It sounds like your friend should get a OBD-II scan tool like VCDS. It's a bit pricey, but you can find used ones. I don't know if there's now 3rd party tools that are nearly as good. But a scan tool is invaluable for diagnosis today and for the future. PLUS, when selling the car, you can either include it as a purchase bonus, or just resell it on an Audi forum.

Cliff, I can attest that the download is fine. It's just a video file. No other "baggage." But if it helps, maybe he could upload it to YouTube and give you a link if downloading any video files is unacceptable to you under any circumstances.

Well, I may have lucked out. I'd cleared the VAG COM codes and the door codes came up again. So, I went to inspect the wire loom of the left rear passenger door. I detached the boot and examined the wires. From the very narrow viewing zone it appears that most of the wires are intact. But I did notice one had insulation cracking, just one running perpendicular to the wire length. I couldn't see very well and wasn't able to detach the black multi-wire plug. I put the boot back and... the door lock works again! It must be a faulty wire and I just need to secure it back together.

That is "weird" indeed! It sounds like an upset elephant. Never heard this before coming from a car engine. My first guess would be a worn belt... but then, it would usually be very consistent and when accelerating. In your video, your car is barely moving and it seems to come on when moving forward and even when stopping. So, it's not brakes. Did you do the clutch and water pump yourself? Or was it done by a reputable shop? Because if it was a shop, I'd take your car back there. Let them diagnose it since they performed work on your car. A water pump can make noises, but usually not like this (and it'll be continuous, not stop/start like this).

How old is the battery in your Audi A4? Was it working perfectly fine until this moment? Do you know why it went flat (e.g. car sat for a long time or you left an accessory on such as a light)? Also, is it a standard lead acid battery or an AGM type?

I've owned 9 cars over the years (some simultaneously) and while my Mazda MX-5 Miata '99 never had a single issue, my ownership was only 3 fun years. My Audi TT QR '03 was also owned for about 3 years and while it had some electrical quirks, they were covered under warranty. But my Audi A3 '07? Phenomenal reliability across 17 years. I put a large portion of mileage on it for the first 2 years of ownership when I had to commute 50 miles each way, every work day. After that, I either worked remotely or took public transportation to work, which helped offset the initial high yearly mileage. The only "performance" mod I've done was a rear sub-frame brace, which helps keep the car level in sharp turns. It's like it's on rails and reminds me of my former TTQR. Cosmetically I replaced the front grille (changed chrome to black) tail lights with amber turn signals, CANBUS compatible LED bulbs for rear turn signals, fog light switch, upgraded rims, and converted the single DIN center panel to double DIN with a Kenwood LED display head unit equipped with two USB sockets (one in glove box, one on side of center console). I was tempted to upgrade to an A5 when it came out, but it was too expensive for my blood. I eventually planned to buy a used one some years later, but my A3 won't quit. And I enjoy having 5 doors. It's like a good, dependable friend. I will be heartbroken on the day I finally give it up (when I can afford an S6 avant!).

My 2007 A3 (had it since new) just crossed 100k miles and it has been the most reliable car I've ever owned. But it hasn't escaped some minor issues, like the decay of wire insulation on door wire looms. About 4 ~ 5 years back I'd had some pesky problems with the window controls and door locking, and discovered it was the driver's door wire loom. The insulation had stiffened, cracked, and caused stress to the copper wire filaments resulting in breakage. I was able to fix the troubled wires and all has been OK, with only 1 exception. The left rear door window. I have enabled fob control of the windows (press+hold on unlock will cause windows to roll down, and press+hold on lock will cause windows to roll up). The odd thing that happens when rolling up is sometimes the left rear window will do the opposite--it'll go down instead of up. And it will be about 4". Basically the window will no longer be responsive for auto open or close. However, I can clear it by cycling manual full open and close and the window will answer to auto open/close. I suspected that it might be a wiring problem but it didn't annoy me enough to try troubleshooting. But now there's another problem. This happened about 6~9 months ago. I discovered my left rear door wasn't locking. Clicking the lock button on my fob would cause doors to lock but there would be no hazard flash or sound. And that's because the left door didn't lock. Somehow, miraculously, the problem went away and the door went back to locking/unlocking properly. That is, until now. I'm having this problem again. Also, I discovered that the driver's door lock controls won't force the left door to lock either. Since this issue cleared up and then returned again, I'm guessing that it's the wiring and not the lock actuator. Is the wire loom repair kit that's used for the front door also the same for the rear door? Here's the kit I intend to buy: Prewired Door Repair Kit Harness Loom for A2 A3 A4 A6 TT.