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Can I flash a 2002 ECU with a 2003 ROM and use it in my 2003 MT?

bluesubaru wrote:Can I flash a 2002 ECU with a 2003 ROM and use it in my 2003 MT?

Just use a 2002 ROM in the 2002 ECU. Should cause no issues in a 2003 car.

...but can I flash a 2003 ROM to a 2002 ECU? The hardware is said to be the same (or close enough).

bluesubaru wrote:...but can I flash a 2003 ROM to a 2002 ECU? The hardware is said to be the same (or close enough).

No. Hardware isn't the same. The 2003 ECU supports a solenoid that isn't present on the 2002 WRX.

But even if that was the case, why would you want to do that?

On second thought, you can flash a 2003 ROM onto a 2002 ECU and use it in a 2003 WRX without the MIL commanded ON if you can disable this trouble code: P1446 - Fuel Tank Sensor Control Valve Circuit Low.

I, like others, wonder why.

Jon, what exactly does that solenoid do?

ECUPancakes wrote:Jon, what exactly does that solenoid do?

It's described on p. 12 of the attachment.

BTW, it was dropped midstream during MY05 Legacy production:
http://www.thel7.com/TSB/11-75-05.pdf

west_minist wrote:But even if that was the case, why would you want to do that?

because I can get a 2002 ECU for cheap. I want to keep my stock 2003 ECU un-modified and use a 2nd ECU (the 2002) in the car and mod that. I would rather work with 2003 code than 2002 code since that is what my car is.

Is that better? I don't know. But I would do it if it is possible.

bluesubaru wrote:

west_minist wrote:But even if that was the case, why would you want to do that?

because I can get a 2002 ECU for cheap. I want to keep my stock 2003 ECU un-modified and use a 2nd ECU (the 2002) in the car and mod that. I would rather work with 2003 code than 2002 code since that is what my car is.

Is that better? I don't know. But I would do it if it is possible.

Just use the 2002 code on the 2002 ECU. It will work just fine.

Hell, with E**TeK reflashes, people typically run 2002 ROMs on 2003 ECUs (in 2003 cars) to enable boost map switching.

x99percent wrote:Hell, with E**TeK reflashes, people typically run 2002 ROMs on 2003 ECUs (in 2003 cars) to enable boost map switching.

+1