Basic Question: ECU version number.

[Spec C Wannabe]

When someone refers to "MY03 Impreza 2.0 WRX (EURO) [AH750-5141] A4TE001G".

What are AH750-5141 and A4TE001G referring to respectively?

[cboles]

AH750-5141 is written on the case of the ECU.

A4TE001G is the actual calibration ID inside the ROM.

of course, if the ECU has been reflashed, what is written on the case can become irrelevant.

[daddyhaw]

How can you tell if the ECU was reflashed before? whether by open source software or by commercial software?

[Freon]

You'd have to compare the ROM images to other know images for matches. I don't think there is any sort of "odometer" or "broken seal" if that's what you mean.

If someone read out their stock ROM image, then did an APflash , then an Ecutek flash, then flashed back to the stock image that was read before any flashing, I don't think anyone could ever tell.

[cboles]

The only giveaways I can think of are:

1. The ROM image does not match any stock image
2. The ROM image does not match what's on the case AND was not a likely dealer update image for what was on the case.

[intrawrx]

Many of the E**TEK Rom's i've seen alter the

A4TE001G calibration ID inside the ROM to something like A4TExxxxx or something similar.

[Spec C Wannabe]

Thank you for all inputs. So Which one is the best to use in referencing each ECU? I guess calibration ID is better right? But will it be changed if I flash my ECU with ECUflash?