Swapping an ECU.

[NMAK]

I have a 1996 MX-3 at 4cyl, and it's ECU is shot my headlights and fans turn on randomly overnight when there set to off and it kills my battery my deck does not get an power either.

Can anyone explain how to swap the ECU, mazda wants $150 bucks, seems pricey!

[solo_ryder]

Very simple.

1. Disconnect the negative battery terminal
2. Pop the kick panel off the passenger side under the dash (farthest panel, should be a plastic clip holding it)
3. Unbolt the ECU and any other sensor attached to the bracketry (10MM socket for this)
4. Unplug the harness from the ECU (screwdriver will help to pry it out)
5. Pull it out

Very simple to do, to put it back in is reverse order.

Good luck.

[NMAK]

Thanks, I'm guessing this 'easy' job is going to be difficult for me without pictures but it's still not worth paying mazda $150 to do it.

So once I plug the new one in I can just start the car up like normal and everything should be fine?

Lastly, does the problems I meantioned headlights turn on randomly, no power to the stereo; sound like problems from a bad ECU?

I've driven 3000+ km on this 'bad ecu' with no problems, I thought the ecu was supposed to control timing and of your engine and everything; is it possible something on the ecu work fine and other stuff is messed?

[shameem]

Sounds like a problem with your alarm system .....

[NMAK]

It does seem to have an autostarter or alarm antenna, I never had a remote for it or ever used it... What fuse would that likely be controlled by, if it is an alarm problem and suggestions on hjow to fix it?

I could see the headlights being an alarm problem but I'd think the deck would work, I checked fuses already.

[NMAK]

Also is there a difference between engine control unit (ECU) and electronic control unit (ECU) or are those the same thing in 1 part, because my engine seems to work fine but my electronics are bugged.

Example: Pulling my brake will turn on my highbeams at times, sometimes it won't.

[NMAK]

My MX-3 is a 1996 at 1.6l 4cyl and the ECU in it says,

B6GE B
B6GF 18 881A
079700 6722
006722H

Someone has this,

B6GDB
B6GD
E G I
B6GD 18 881B
079700 - 6712
This is marked as being from a 1996 1.6L MX3
Unknown if AT or MT ECU

I'm guessing this WON'T work, does anyone know, is this for a manuel, would it work anyways?

[NMAK]

Here are the problems I am having with my MX-3 1996 4cl automatic,

- Lights automatically turn on at night, no key, headlights set to off
- Pulling E-Brake can activate turn brights on when set to just headlights
- Pressing the Brake peddle can turn on vents then stepping off peddle turns them off, with no key in ignition (vents must be set on though)
- Check Engine Light is on, vehicle runs great I've done 10,000km on it.
- Deck does not receive power (Fuse is fine)
- Turning headlights to off position after being on headlights occasionally makes buzzing noise and the dash lights flicker, switching the headlights on and off a few times will eventually make it shut off like normal

Is this my ECU or my Body Control Modual?

[shameem]

The Engine Control Unit (ECU) has no connection to the headlights and other lights - There's a Central processing unit (CPU) located in the driver side (for North American cars) and that may control some of these functions.
But most likely you have a major wiring problem that is cross connecting multiple systems and doing weird things.