96 taco buzzing noise in engine
 

96 Tacoma 4x4. When the car is off, I hear a buzzing noise in the engine compartment. It's coming from the drivers side. I goes off every 15 seconds or so. It almost sound electrical. But it is right on cue every 15sec buzz....buzz...buzz.
Any ideas?, please help.

its the ECCS. its just checking all the sensors and shutting down