B4 - '97 Passat; VR6
For some time, about 2 out of 10 times when I started the car, I would hear a buzzing sound behind the instrument cluster that sounded like a small relay chattering. Since I had gotten the recall letter and already knew that the ignition switch was flakey, I had always been explaining it away as just another symptom of the bad switch.
Well, I had the switch replaced and the problem didn't go away, so I was inspired to do a little Owners Manual reading, a little Bentley book investigating, and a little symptom watching.
What appears to be happening, is that still about 2-3 times out of 10, when I start the car, I hear the buzzing and the clock and MFI resets. What I've learned is that the buzzing isn't a malfunctioning relay, it's a "properly" functioning Oil Pressure Warning Buzzer. The manual says that at "start", the oil pressure idiot light is supposed to come on and/or blink as a "test" and then go off after the car is running. When things work properly, that's exactly what happens.
On those 2-3 times, I've noticed that when I turn the key to the "start" position, the oil pressure idiot light DOES NOT come on and I get the buzzing sound, presumably from the Oil Pressure Warning Buzzer. I can't say how it's related, but when this happens, the clock always resets to 01:00 and the MFI memory is also cleared.
Any ideas?
TIA-trebor