Ok, this is on a 96 OBW 2.5EJ with auto tranny. Notice the other night, with the engine off, but in gear, and the with ignition key to accessory (instrumentation gauges lit) a strange buzzing sound coming from underneath the car, somewhere around the tranny. At first I thought it may be coming from one of the O2 sensors, but the buzzing still there when I disconnected them. The buzzing stops if I put the tranny into Park or Neutral, but buzzes in drive, 1st, 2nd, 3rd. C-Selanoid? Fuel Pump?

 

Anyone know what this it, and if it is something I need to look into further? It's probably normal, I just never noticed it before...

Nope that's normal. The TCU controls many of the AT's solenoids with a 50Hz square wave of varying duty cycle. I can hear it too with engine off, key on, in gear. Some people say they can hear it with engine on too.

Nope that's normal. The TCU controls many of the AT's solenoids with a 50Hz square wave of varying duty cycle. I can hear it too with engine off, key on, in gear. Some people say they can hear it with engine on too.

 

Thanks. I had an inkling that's all it was. Never heard it before on this car, and with it getting up in years and miles, wanted to make sure it wasn't something that was beginning to fail.

Anyone notice the fuel pump kicks in when you tap the pedal at like 1/4 throttle? with key at ignition on but engine not started.

Hm..really? I'll have to try that out. Maybe we should start a list of subaru tricks.