I would like to ask for some advice regarding replacing the ECM in a 2005 MT 192 RX-8. The original ECM was damaged (impact rather than electrical) and I was intending to replace it with another from 2004 MT 192 RX-8.

I understand that the Mazda system has several components in the ECM/Immobiliser system and have the following components from the 2004 doner:

• ECM
• Keyless Receiver
• Keyless Module
• Matching Keyfob and keys
• Ignition lock and coil

My first query if, I switched over all these components, would the vehicle start? In principle I can't see why it shouldn't (of course the VIN won't match from ECM to car, but I'm not concerned about that), since these components should function as complete system. However perhaps I am wrong?

Secondly, on searching for the Keyless receiver I was unable to find it in the specified places, and finally discovered that in this RX-8 both the Keyless receiver & Keyless Module are combined. While the connectors remain the same, the wiring is slightly different as the host car includes a theft derrent system. I've studied the wiring loom and believe that I can still connect the replacement components I have (linking the receiver and module together with soldered wiring). This is not particulary ideal though, and I wonder if anyone can advise whether this combined keyless unit is the norm now?

Lastly, the preferred option is to solely replace the ECM, keep the original keyless components, keys etc and have the dealer reprogram the ECM. Unfortunately, on speaking to my local dealer, they seem to think that it isn't possible to reuse an ECM from another vehicle and suggest I'll need a new one at a cost of $4000 plus labour!

I've done some searching through the forums and it seems that it should be possible to reuse a secondhand ECM via the i-DS system, can anyone confirm this ?

Is another option to purchase a J2534 pass-thru device plus a subscription to Mazdatech and try and blank/flash the ECM?

I'm in the UK, and the car is a RHD.

Many thanks for your wisedom

Mike

 

pm rotaryresurrection

 

^ ay, rotaryresurrection just did an at->mt swap that involved intricacies with getting the ECM over.. I know he did in fact get the dealer to flash a PCM he already had in his possession over to his new setup... so just got to find someone willing to get their hands dirty.

 

find an 05 PCM , have it reprogrammed and save yourself a lot of grief

 

If you use all the components from the donor car as you mentioned you will have no problem whatsoever and can avoid the dealer for any programming. This is how we sell our computers (As CAN kits).

Paul.

 

"If you use all the components from the donor car as you mentioned you will have no problem whatsoever and can avoid the dealer for any programming. This is how we sell our computers (As CAN kits)."

If I have no luck with my current setup, would I be able use a CAN Kit from yourself in a European car or would it cause problems?

Is the coil a critical part of the immobiliser system, i.e does it have to match, as I can't see anything from the documentation that makes it unique from car to car?

Thanks for all the advice and comments.

Mike

 

I don't believe that the US items can be used (I could be wrong) and the coil itself isn't coded and therefore not critical to the best of my knowledge.

Cheers,

Paul.

 

Thanks for all the help.

I studied the schematics for the keyless receiver module and receiver unit from the donar car, and the original combined module and receiver from the host car, and worked out the differences. Four additonal electrical connections and a few seconds of nail-chewing nervousness later, I have a working car with no unusual dash lights, no CEL light and all keyfob functions enabled. :-)

Engine is running beautifully, so thanks to all for their help and if anyone else ever tries to fit an earlier PCM and associated components into a later car, let me know if I can help.

Cheers,

Mike