Has anyone swapped the ECU before tuning?

NHCivicGuy

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Just out of curiosity, has anyone with an Si swap out their ECU with a donor one and flash that? That way you can keep the original one in tack. I know this would probably involve having the immobilizer keys reprogrammed, right? Anything else needed? Just a thought..
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It would need rekeyed, but it's a bit more complicated than you're thinking. Once rekeyed, you wouldn't be able to swap the old ECU back in.

There's really no reason to do that, by the way. Reflashing to the OEM calibration returns the ECU completely to the original calibration if using KTuner. Hondata flashes everyone to the same base code...
 

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Yes you'll have issues with the immobilizer. You'd need to go to the dealership
 
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It would need rekeyed, but it's a bit more complicated than you're thinking. Once rekeyed, you wouldn't be able to swap the old ECU back in.

There's really no reason to do that, by the way. Reflashing to the OEM calibration returns the ECU completely to the original calibration if using KTuner. Hondata flashes everyone to the same base code...
My thoughts were that because the ECU holds the max boost and other variables, it would cause issues if a major warranty issue came up down the road. Just figured to play it safe with a donor ECU, but this just about confirms my thoughts on the process being involved.
 

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You're referring to "freeze data."

Freeze data is tied exclusively to a DTC code. If there's no DTC code, there is no stored information.
 


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You're referring to "freeze data."

Freeze data is tied exclusively to a DTC code. If there's no DTC code, there is no stored information.
So my thought on this is that as long as you flash back to factory, and clear all DTC codes, there shouldn’t be any indication that anything was changed.
 
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NHCivicGuy

NHCivicGuy

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You're referring to "freeze data."

Freeze data is tied exclusively to a DTC code. If there's no DTC code, there is no stored information.
So my thought on this is that as long as you flash back to factory, and clear all DTC codes, there shouldn’t be any indication that anything was changed.
That is true, however a member on here and on the Facebook group, who works for Honda directly, stated that there is a special tool that Honda (corporate) has that can retrieve stored data even after you flash back to stock. These values included the amount of times the ECU was flashed, history of max boost and other statistics. I am not a Honda tech nor do I work for Honda corporate, but I definitely believe this is possible. They probably wouldn't go through all of this trouble unless it was a major repair, such as engine failure, etc. where they're researching to figure out the real cause of what went wrong.
 

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Yeah, that guy believed the lies his dealer told him hook, line, and sinker.

The special tool is the HDS, and it can't read a reflash counter that doesn't exist in the ECU.
 

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It would need rekeyed, but it's a bit more complicated than you're thinking. Once rekeyed, you wouldn't be able to swap the old ECU back in.

There's really no reason to do that, by the way. Reflashing to the OEM calibration returns the ECU completely to the original calibration if using KTuner. Hondata flashes everyone to the same base code...
So once you flash with Hondata you can’t return the ECU to the original calibration? Just trying to understand. Can the Hondata “base code” be seen as different from stock? I had Hondata, reflashed/unlocked and now am on KTuner.
 

JN259

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Yeah an engine failure is kinda when I’d really want my power train warranty. I’m really hoping we can start getting some consistent answers on what can and can’t be seen when reflsshign with Ktuner.
 


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Yeah, that guy believed the lies his dealer told him hook, line, and sinker.

The special tool is the HDS, and it can't read a reflash counter that doesn't exist in the ECU.
Can you shed some light on what it can see?

As @JN259 said, there's been a lot of mis-information.
 

D-RobIMW

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If there is no DTC, there is no stored "freeze data".

Key cycles since last DTC clear is visible, so that may be a little incriminating if you reflash right away, but a battery terminal disconnect will do the same if you're questioned about it.

Find a Honda dealer that does a big volume. They usually warranty everything, to be honest.
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