When I first purchased the car, I did actually have and noticed the fault wiring on the car door. At the time I carried out a quick bodge to repair the door wiring on the A3. This is about 3 years later however the solder eventually broke down from the constant opening and closing of the car door. I now need a permanent repair so that it doesn’t keep happening, hence the need for this repair kit as I had an MOT due, and an airbag light appeared on the dash. Original article : https://www.andrewhope.co.uk/Blog/repairing-audi-a3-door-loom-to-fix-g179-airbag-faultCourtesy of https://www.andrewhope.co.uk
Safety precautions for repair the door loom
I decided because I was working with the door loom, and the airbag system on the Audi A3, due to the error relating to the G179 sensor. That I was going to disconnect the battery as a precaution, and discharge any residual charge in the system
In order to do this, I first used a 10mm spanner and disconnected and removed the battery from the vehicle. I disconnected the negative terminal first, then the positive.
I then touched the two terminals together for abotu 20 secs to remove any charge. At this point, I then held my foot on the car brake for another 20 seconds or so which would help discharge any remaining power in the system via the brake lights.
What error messages did I get for the G179 sensor?
As you can see below, this is the direct error message I received relating to the G179 sensor when scanning my car with VCDS. This matches up with the fault code I received, and the visibly damaged wire after carrying out the repair. the Airbag connection wires are powered through the main harness (which is done via Pins 1 + 11) which is the main power and ground wires. The airbag connector is powered through wires (5+6), which when looking at the photos the brown wire was broken. This is why I kept having an intermittent fault when opening and closing the door.
1 Fault Found:
01221 – Crash Sensor Side Airbag; Driver Side (G179)
011 – Open Circuit – Intermittent
Freeze Frame:
Fault Status: 00101011
Fault Priority: 2
Fault Frequency: 17
Reset counter: 246
Mileage: 249680 km
Time Indication: 0
Date: 2024.08.04
Tools and Supplies used to repair the Audi A3 loom
- Audi A3 Connector repair kit (available on Amazon and eBay)
- 10mm Spanner
- Heathshrink Butt Connectors
- Butane Gas Soldering Iron (for heatshrink)
- Ratchet Crimp Tool
- Insulation Tape
- T20 Torx Screwdriver
- T25 Torx Screwdriver
Fixing the Audi connector and G179 Airbag light
After carrying out preliminary safety precautions on the vehicle, I was free to work on the connector. I first needed to remove the door card, this is held in by screws at the base of the door, under the armrest, and behind a hidden panel at the top of the door. These are removed with T25 torx screwdriver
After the screws are removed, you can pop off the door panel. You need to unhook the cabling loop securing the door (no picture), the door will then hang loose, still held on by the cabling for the drivers control panel. This is disconnected by lifting the purple flap. you lift this upwards, whilst depressing the switch above it until it’s fully verical. After this is done, you can remove the connector by simply pulling it. Which releases the door panel. Put to one side
After the panel is removed, you need to disconnect the wiring connected to the door speaker, this is done by pinching two clips at the top and pulling. Then unscrew the speaker from the door panel, by removing the 3 x T20 Torx screws securing it. After it’s removed, the wire is held onto the door clip by a plastic fir tree plug. This can be pulled / snipped off
Whilst you shouldn’t need to do this, more for information, if you need to disconnect the modules from the door connectors for any reason, you do this by pulling on the red locking tab, you then press the locking tab inwards (pictured at the screwdriver), and pull it away from the module, it is then removed from the module
Now that all parts are accessible, I decided to cut the old wiring on th efaulty connector, retaining some of the wiring so that I had something to work with, as I now had a replacement connector for the car to repair it
The replacement connector kit has 30cm pigtail leads on the connector, which is plenty for the wiring. I added a corrugated tube over the wiring for a bit of protection, then fed the wiring the door speaker access hole. I then went through the long and slow process of repairing the connector. I tried to make this easier for myself with a system of feeding one wire through the corrugated tube at a time and joining the wires together with but connectors. I crimped the terminal fully and did a pull test on every wire. After the pull test was complete I used my gas soldering iron to melt the heat shrink in place. Throughout every step of the way, I verified the old connector against each wire when I was doing the repair. I also made a system of folding every wire out of the way once I was finished the repair, so I only worked with a live wire each time.
After I had finished carrying out the repair on the Audi A3 door connector, I wanted to clean the G179 sensor. I didn’t feel that I needed to do this, as I believed the failure was more down to wiring because of the initial tests. However the cover was already off, and I didn’t want to do everything again.
I cleaned the electrical connectors of the G179 sensor, by disconnecting the plug. This was done by pulling the red locking tab downards first, then once it was disconnected. I could simply pull down on the connector to unplug it. After the connector was unplugged, I sprayed some Electrical Contact Cleaner into the housing, and left it to dry out for a short while. I also used a multimeter on the terminal pins of the connector for the G179 sensor, and the multi plug wires to verify I had a working system (I did obviously).
Reference pictures if required
If required, this is the numbering of the pins, and what each wire “should” do I believe based on wiring diagrams that I read. The items with question marks I believe are correct, the only one I’m unsure on is the black wire (pin number 18) as I couldn’t find any info on this. I put this here as a point of reference in case it is useful to anyone. I’ve also included a Youtube video on this below
Youtube video on the wiring breakdown of the connector above
After the repairs were carried out the loom was fully repaired. I fed the loom through the access holes in the door, and firmly connected it until I heard a click on the housing. I then reattached all the items back to the door, panel, speaker and screws
Calibration of the steering system to clear error lights
After reconnecting the battery on the vehicle, and powering up the car, the Airbag light went out, however the ABS/ESP/Steering lights were all lit up on the car. This is a standard error that you get after disconnect the battery
All that is needed is a quick procedure. In order to clear the fault lights on the dash after reconnecting the battery on the car you do the following
- Turn the steering wheel full lock to the left
- Turn the steering wheel full lock to the right
- Centre the steering wheel
- Drive the vehicle
- After approximately 100 yards/30mph, the error lights on the car should disappear
After I returned the error lights were gone, and the Airbag light was out on the vehicle, confirming the fault was rectified
Original article : https://www.andrewhope.co.uk/Blog/repairing-audi-a3-door-loom-to-fix-g179-airbag-fault Courtesy of https://www.andrewhope.co.uk
