How do I identify an open circuit?

[Riva811]

Hello, over the past two years I noticed the following funny things happening to my car with no diagnostic data:

1. Unexplained battery drain
2. Front parking sensors being too sensitive
3. I had the dashboard buttons were not functioning on one instance
4. Parktronic usually turns to four dots
5. Cracking noise via speakers and then audio is lost.

I started getting more diagnostic errors now and the symptoms are a lot worse:

• If the car is off for more than 8 hours, cracking noise and audio loss is immediate on starting the car. Audio returns after the car is switched off for an hour or so.
  
• I finally got an error from Parktronic complaining about data received from ESP
• I did get an error about an open circuit, i tried to store it on the diagnostic and then cleared the code. To my surprise it wasnt recorded and now i am no longer getting the error code.

Any ideas on how to find the open circuit? Or shall I wait for the diagnostic code to show up again?
Car is a C216 facelift

 

[Wolfie1]

If you have no idea where the open circuit is/which system you will never find it tbh

 

[Deleted member 65149]

Sounds to me like a loose connection somewhere. The first and easiest place to check will be the battery connections and the end of the battery cable that connects to the car’s bodywork.

 

[Wearsthefoxhat]

What is the condition, age of the battery as a failing battery can cause stupid, odd faults.
I would also turn everything off in the car before removing the key, might be a command not shutting down problem ?
An open circuit is just that, a broken wire and something not working, not getting a voltage or signal.
As above begin by checking connections around the battery and earth terminals.
Hope you get it sorted.


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