Alarm going off

[geoffreytro]

Hi,
First post on my 2015 Audi 1.6tdi. By bad coincidence my Audi A3 has developed the same fault as my previous A4 Cabrio and the alarm goes off when the car is locked. Never solved the A4 and removed the alarm so only the lights flashed when the alarm went off.

Car is original with no mods and I have driven since October 2019 with no issue.

VCDS has three faults - one of which is the fuel cap which failed over a year ago (it does not lock). The remaining two and new faults are a fortnight old (per VCDS). Scan of faults only are below:

263435 - Glass Breakage Sensor B145F 13 [00001000] - Open Circuit Intermittent - Confirmed - Tested Since Memory Clear Freeze Frame:
Fault Priority: 6 Fault Frequency: 35 Reset counter: 52 Mileage: 152851 km Date: 2024.08.07 Time: 11:39:33 Terminal 15 status: OFF Terminal 50 status: OFF CAN-Bus_aktiv: On Status Bremslichtschalter (HW): OFF Status Bremslichtschalter (CAN): OFF OFF: Not operated Position lamps: Not operated Automatic high beam assist: operated Low beam: Not operated Parking light left: Not operated Parking light right: Not operated last_wakeup: g�ltiges Funktelegramm Voltage: 12.3 V Outside temperature: 17.5 �C

395521 - Function Limitation due to Active Protection Function B2023 00 [00001000] - - [St�rschutzz�hler�berlauf] Intermittent - Confirmed - Tested Since Memory Clear Freeze Frame: Fault Priority: 6 Fault Frequency: 16 Reset counter: 52 Mileage: 152719 km Date: 2024.08.05 Time: 09:26:43 Terminal 15 status: OFF Terminal 50 status: OFF CAN-Bus_aktiv: OFF Status Bremslichtschalter (HW): OFF Status Bremslichtschalter (CAN): OFF OFF: Not operated Position lamps: Not operated Automatic high beam assist: operated Low beam: Not operated Parking light left: Not operated Parking light right: Not operated last_wakeup: Pin A51 IR� Deaktivierungstaster: Heckscheibenbruch Voltage: 12.5 V Outside temperature: 18.5 �C

I have googled and found nothing. I removed the rear hatch trim and nothing seemed untoward. All plugs, wiring and connections appears in good condition. No breaks in rear demister wiring and checked continuity which was fine.

No leaks from rear washer and all looked good.

Wires under rubber connecting hatch to the car body looked good. In particular checked white wire as this was the only thing I found on google.

Is an open circuit a needle in a haystack and I just need to remove the alarm and/or trade in the car.

[geoffreytro]

Car alarm error fixed. I replaced the actuator that locks/unlocks the fuel flap (when locking the car). This fixed the problem and the alarm no longer randomly sounds when the car is locked and parked.
i changed the fuel cap actuator over a month ago and the alarm has not sounded in error over the same time.
Previously the alarm would randomly set off as the car was sitting locked on the drive to the annoyance of neighbours. My temporary solution was to leave the car unlocked.
However changing the actuator fixed the problem and I now have no more false car alarms, and, as a bonus, my fuel flap locks when I lock the car.
Simple lesson- fix faults when they arise as the fault may develop into something else. I didn’t think that a faulty fuel flap failing to lock, would extend to false car alarms.
Hope this helps someone else frustrated by random false car alarms.