i have a buzzing sound (maybe an alarm) and its being caused by my ECU, i know this because i when i took the fuse out of the ECU the buzzing stopped. Why would this be happening and is there a downside to not having the ECU working?

 

Have you tried unplugging the oscillator yet?

 

Hey Ray, how have you been man!
Can you take a pic of the oscillator and plug? I had this problem and did a search and saw another thread where you had mentioned doing this, but had a hard time following the diagrams in the Haynes. Thanks in advance!

 

Howdy Ian!

I don't have a picture handy, but the oscillator is easy enough to find and unplug. It's attached to the front wall of the engine bay right in front of the battery, between the driver's side headlight and radiator. Some of them still say "oscillator" on them. You may need to move the battery to get to it.

Unplug it, if the buzzing stops you've found your problem.

Usually just plugging them back in ends the buzzing, which seems to be related to moisture and corrosion getting into the electrical connection, especially in cool wet climates like Portland.

Since the oscillator doesn't seem to perform any critical function (unlike like the ECU; Engine Control Unit, get it?) it can just be left unplugged if necessary.

 

you're referring to the black box/relay looking thing bolted to the chassis with a 10mm bolt? I was wondering what that was. what's it actually do?

 

Ray, is this the guy you are talking about?
[IMG][/IMG]

 

You mean that rectangular black box in the middle of your picture that says "oscillator" on the side of it?

Yep, that's it. I don't know what it does.

Unplug that electrical connection down on the bottom to fix the oscillator screech.

 

Awesome. Thanks!

 

i have now searched my engine compartment 3 separate times and have yet to find any "oscillator", i have also looked through my Haynes and didn't see any mention of an oscillator in it.

 

my ECU says emission control unit not engine control unit

 

Yeah, I don't think the Haynes mentions the oscillator and I haven't seen it in the FSM either. But all FBs have them.

And nobody seems to know what the oscillator does either, except make a screeching buzzer sound sometimes, especially when it's cold and wet.

You should post a couple pictures of the left front of your engine bay, one with the battery installed, the other with the battery removed.

I'll bet we can pick out the oscillator.

Concerning the ECU, it works with the Nikki to control air and fuel delivery to the engine to maximize power and efficiency and minimize emissions. That's why I call it an Engine Control Unit.

 

you say the oscillator makes the buzzing sound? if that is so then its not my problem, mine is comming from inside the dash, not the engine compartment

 

Its a ventriliquest Oscillator..

 

Like Robert says, the oscillator is an excellent ventriloquist.

It's located on the front side of the engine compartment, but its sound emanates from some nebulous place under the dash.

Anyway, enough Philosophy. Why don't you just go out and unplug the damn thing and see what happens?

It takes about 5 minutes to move the battery and another 5 seconds to unplug it.

 

.

 

You should post a couple pictures of the left front of your engine bay, one with the battery installed, the other with the battery removed.

I'll bet we can pick out the oscillator.

 

Fixin to take care of the problem. I will post pics as I go along for a little write -up.
But, it really is right where Ray said it was. Behind the drivers side headlight and the battery, mounted to the frame that holds the headlight assembly. I will have to remove the battery to access it. Gimme about an hour to wake up and get some coffee in me and I will post the pics.

 

finding and and removing it is great and all... but i'd like to find out what it's there for.

 

"It takes signals from those respective sensors (low coolant, oil, etc maybe) and produces an audio signal which is reproduced inside the dash somewhere...." Found on another post. I don't think mine actually works either.

 

Mine works, just when there is not a problem it produces a low scratchy sound that is annoying as hell. I am getting ready for the Dragon, so have flushed and filled the coolant, did an oil change and anything else it should sound the alarm for is good to go. I am going to clean all the connections and put it in to see if that helps. In the meantime..
Here is where it is hiding:
[IMG][/IMG]

Here it is with the battery removed:
[IMG][/IMG]

I disconnected the 2 connectors:


And here it is out of the car ready for cleaning:


You can see some oxidation on the connectors, so a quick wire toothbrush action, some electric grease and we should be back in business!

 

Its in the Factory Wiring Diagram. Section C. From looking at the schematic, that is correct. It provides the path to ground for the low coolant or oil buzzer in the dash. If the sensor for either goes low, the oscillator's internal transistor cap and resistor circuit energizes and bias the buzzer transistor, allowing current to flow through the buzzer, through the oscillator and go to ground X-14. Due to the configuration of the load resistors, two caps and two transistors, the base bias of the output transistor should switch on and off, or oscillate, creating the buzzing sound in the buzzer in the dash.

 

To verify for you guys, the oscillator causes a buzzing noise to occur when there is low oil or low coolant. If you remove the oscillator, There will no longer be a buzz related to low oil or coolant but the dash lights will still come on when they should. I learned this because I had a coolant leak so my low coolant light and buzz would come on about once a week. At one point, my oscillator started screaming all of the time. After I removed it, the low coolant light still came on, but the buzz was no longer there.

 

Mine was screaming all the time, but hasn't since I removed it, cleaned all the connections, and reinstalled it. Now just to wait and see when something is low to really test it.

 

Instead of waiting, unplug the oil level sensor and touch the conductor on the harness side to ground. This will activate the buzzer.

 

I thought mine didnt work on my SE, until I drained the oil with a friend and left the key on. It was the ugliest racket to ever come from that car, so I could def understand removing it forever and jumping up and down on it until its a fine dust.