What is this and where in the FSM can I find it. I looked but didn't see it in any of the diagrams...

 

To my knowledge no one really knows. It's not on the USDM ecu's so you won't find it in the FSM.

 

It's the infamous mystery black box on J-spec ECUs. I've read some threads that speculated what it was for, but nothing for sure.

 

has anyone ever called mazda and actually asked what its for? it seems to have a part number on it so they should be able to figure something out about it. or maybe get ahold of a jspec fsm or something like tht.

 

Looks like it's an electrical load module:
http://www.ausrotary.com/viewtopic.php?f=4&t=133608

 

^ That's interesting, since US-spec S5 ECUs have the electrical load / idle control feature built into them. That'd mean using an N374 would give you a less stable idle, since there's no way to hook that black box up to US wiring.

 

I was wondering the same things as OP. I have one of those ECUs as well and dont know if its worth keeping or if it should be tossed

 

Sounds like I need to get my hands on a jspec fsm and then take it to my jp speekin' buddy...

So supposing it's an electrical load thing, what are your guesses for what it does? How it helps, it's purpose... ?

 

Read the thread linked to above and my 2nd post. Idle speed stability.

 

It's the driver for the exhaust temp sender in the cat on the JDM cars.


regards

 

i've never seen one before. if it is for the exhaust warning light you could probably just toss it, the circuit doesn't even work on the USDM cars.