Connecting an OBDII scanner can sometimes lead to unexpected issues, such as triggering your car’s alarm. This article explores a peculiar scenario where repeatedly locking a vehicle with an OBDII device plugged in can set off the factory alarm system. We’ll delve into potential causes and discuss possible solutions.
OBDII Devices and Car Alarm Interference
A car enthusiast recently reported experiencing an issue with their 2017 Audi S3. After installing a P3 gauge and later, using a BlueDriver Bluetooth OBDII scanner, they noticed the car alarm would sound when the vehicle was locked twice in quick succession with the device plugged in. This occurred regardless of using the key fob or the door button, and proximity to the vehicle didn’t seem to matter.
The alarm only triggered when the car was locked twice rapidly, not with a single lock or after a longer interval between locking attempts. This behavior was discovered due to the owner’s habit of double-checking the car’s lock status. The Audi S3 only provides visual confirmation (flashing lights) on the second lock attempt if the car is already locked, accompanied by an audible beep. This double-locking routine unintentionally revealed the issue with the OBDII devices.
Testing with both the P3 gauge and the BlueDriver confirmed that the presence of an OBDII device in the port was the common factor triggering the alarm. It appears the second locking action, when performed quickly after the first, somehow interacts with the connected device, causing the alarm to activate.
Possible Explanations and Solutions
One theory suggests that Audi vehicles may have an OBDII security sensor integrated into the factory alarm system. When the alarm is armed twice in quick succession, the second arming might detect a signal, data request, or power draw from the OBDII device, interpreting it as a potential threat and triggering the alarm. This is supported by anecdotal evidence of similar issues reported with BMW vehicles and certain OBDII accessories like Valentine 1 radar detectors.
While online research didn’t yield much information on this specific Audi issue, similar reports involving BMWs suggest this phenomenon might not be brand-specific. It highlights a potential incompatibility between certain OBDII devices and vehicle security systems.
Unfortunately, there aren’t many easy solutions beyond unplugging the OBDII device when not in use or avoiding the double-locking habit. Further investigation is needed to determine the precise cause and identify potential workarounds. This could involve consulting with Audi or the manufacturers of the specific OBDII devices involved. For now, awareness of this potential issue is crucial for car owners who use OBDII scanners or other accessories.
