RotaryDrama

To make a long story short my car will not start because the ECM is dead. I have a...

2004 Rx8 MT Transmission

How do I go about choosing the correct ECU?? Can i just get a 2005, 2006??? I have searched but found limited info on this topic and it doesn't tell you how to choose. If the info is indeed here in the forum give me a keyword and I'll search or if you can just throw me a fish i would greatly appreciate it.

thanks

FazdaRX_8

iTrader: (1)

I am pretty sure you need an 04 for 04

dannobre

iTrader: (3)

You need an 04 MT ECU...and you need the as built data from Mazda to get it programmed

The dealer tech will need to have a clue...it isn't always an easy program. Sometimes it takes a few tries to get it to work

Rotaman

It needs to have the correct numbers, take the cover off your cars ECM and write down the numbers that start with N3_____ and end in a letter.
This is the number you need to match, although there are a few that could be used.
Ideally matching it to the same year is what you are after.

Rotaman

9krpmrx8

iTrader: (46)

We swapped a 04' MT ECU to another 04' MT and it didn't work (wouldn't even crank). So really you need the build data loaded to it. But maybe some get lucky?

RIWWP

iTrader: (2)

I'm fairly sure that if you want as plug and play as possible, you will need same year, same trim/package, same transmission, and you will still have to have a dealer tell all the other modules that it's ok to talk to that ECU (immobilizer, BCM, ABS...)

9krpmrx8

iTrader: (46)

I agree, I think it was a security issue, we had lights but no crank. The two 04''s we tried it in were both GT's so essentially identical except for navigation, but one was a early 03' build date and the other late 03'. We just did it to see if it worked.

dannobre

iTrader: (3)

I have done it.......with the as built data and a tech that knew what he was doing it took about an hour.

It was a relic of Hymee's flash tuner experiment that never finished ;-)

RotaryDrama

You wouldn't happen to have an extra 04 MT around that you could sell me would you? I can't post on the classifieds yet.

RotaryDrama

i have located a N3H6 18 881G but i have a N3H6 18 881F

So Mazda should be able to use this USED ECM as long as they use the "As built data" option?

dannobre

iTrader: (3)

It should work....dont let them give up...they would rather sell you a new one. The directions need to be followed to the letter. .or it wont work :-)

Rotaman

According to the list I have of US model RX8's, the superseded number for your N3H6 - F is what you have located. So yes the N3H6-G is compatible.
Infact you may be able to just plug it straight in and start it if your car and the car that ECU came from had the same specs.

Rotaman

RIWWP

iTrader: (2)

No, you can not.

Every single module in the RX-8 communicates with the ECU, and every single module has specific coding that is looking for the specific internal serial number of the ECU it is talking to. If it sees another ECU that doesn't have the same serial number, they refuse to communicate.

The key one in question is the immobilizer. If the immobilizer is expecting serial number 1356av84nvb94, and you have 0q14t8qg49v5 installed, the immobilizer won't let the car fire.

Same with the body control module, abs module, keyless entry module, etc... You have to have a dealer hook up to them and give the modules the new serial number to talk to. Or someone with the dealer's equipment.

Rotaman

Forgot about the immobilizer system, we don't seem to have immobilizer here in NZ, not in the Jap imports anyway.
This ECU will be fine though.

Rotaman