Hi, I attempted to start my 2015 Golf today and it won't turn on. I never replaced the battery on it.

When I turn on the ignition the dashboard lights start flickering and random error codes are popping here and there very intermittently (regarding Airbag, ESG, driver door etc.). If I leave the ignition on for long enough, the dashboard lights stabilize most times. But the car never turns on on ignition key crank. Matter of fact, the lights go out when I crank it.

I had someone come over and attempted a jump start with no success.

It also feels like the brake pedal is somewhat stuck, not as loose as what I remember when pressing with my foot. When I lock the car using the key it does not lock the door on first attempt.

I don't recall any clicking or grinding sound when I try to crank so I believe it's not the starter.

Any idea what could be the issue or how to further diagnose? I haven't tried starting it with my spare key yet or changing from P to N and back.