GLC Hybrid Anti-Theft Alarm Issue

A malfunctioning anti-theft alarm system can certainly be frustrating When you say 'non-functional,' do you mean it doesn't trigger at all, even when you try to manually activate it (e.g., by locking the car with a window open and then reaching inside)? The error memory is key here If you can provide the exact error code, that would be beneficial However, based on your description, it sounds like a potential issue with the 'alarm control' module or a misconfiguration Sometimes, these systems can be accidentally coded to activate 'optical locking' (indicators flashing) without the audible alarm The 'immobilizer' is a separate system that prevents the engine from starting if the correct key isn't present; it's less likely to be directly involved unless you're also experiencing starting problems What does the alarm sensor measure?

Yes, by 'non-functional' I mean the alarm doesn't trigger at all, even when I try to set it off manually as you described Sadly, I don't have the exact error code at hand right now, but I'll try to get it as soon as possible I am really wondering what is optical locking and how it relates to the alarm system Also, is it possible for a simple coding error to completely disable the entire alarm function?

You're welcome 'Optical locking' refers to the confirmation of locking/unlocking the vehicle solely through the flashing of the indicator lights, without any accompanying audible beep or alarm sound Some systems allow you to choose whether you want both visual and audible confirmation, or just the visual Regarding your question about a coding error disabling the alarm, it is indeed possible A misconfiguration within the alarm system's control module could prevent it from arming correctly or from triggering when it should Given that you've already tried the manual activation test and it failed, and considering your vehicle's mileage, it would be prudent to have a qualified workshop check the alarm system's coding and perform a diagnostic scan for fault codes Ignoring it could lead to bigger problems down the road

Okay, that makes sense Thank you so much for clarifying the 'optical locking' concept and confirming that a coding error could indeed be the culprit I will definitely take your advice and bring it to the workshop for a diagnostic scan It is possible the alarm system was coded to activate optical locking As a follow up, I wanted to report the car is now fixed The repair cost was 45€