There is very little information online about the advantages of purchasing an ECU with the highest version alphabet - which means the most upgraded version.
My question is - what kind of benefits come to the purchaser? Are they noticeable? Or are they things you can never notice?
My original ECU is GY04-18-881E but am purchasing GY04-18-881R0H as its replacement
A good example of the issue at hand is 2001 - 2003 Toyota Rav 4 ECUs and the destruction of transmissions as a result.
Which was so bad that either the ECU had to be repaired or replaced correctly or the transmission would have to be replaced.
My vehicle is a Mazda MPV 2000 California Emissions with anti-theft model.
if you want to buy that ECU today you cannot find the original part number from Mazda only the updated version, hence i wanted to know what benefits could likely come from purchasing the latest version!
The truth is unless I go to a break yard, I can't even get the original part. I know ECU information is proprietary but in general terms and without breaking any laws or agreements - how do I benefit by purchasing the latest version?
Additional Edit: Here is an ECU change in which a newer version replaced the older version ECU replacing procedures
Additional Information here: Installing a used ECM
If you don't match the part numbers, then you may run into issues with software and hardware revision levels, because I did. Please pay particular attention to the comments by @Kilo:
Blockquote I work in this field. I'm an embedded engineer who writes code for instrument clusters and ECUs.
Blockquote ECM (or ECU) often have stickers on the back of them denoting both a hardware revision level and software revision level. I would make sure both those values match the old module you are replacing or that you have some sort of confirmation that the one you are purchasing is backward compatible.
Blockquote ECU/ECM are essentially single board computers specialized to marshall data on & off a CAN or LIN network - some ECUs are apart of a MOST ring. Depending on what networks (CAN, LIN, MOST, etc...) the hardware & software of the module really determine how compatible the unit will be in your vehicle with other ECUs on the bus.
In particular, the EEPROM on the original PCM was a 77005, the EEPROM on the replacement PCM was 77014, according to the locksmith that was why copying the data over did not result in the car starting. I now have to either source for the exact same part number, or a remanufactured PCM and immobilizer from the dealer at exorbitant cost or try to find an immobilizer emulator to enable me to use the replacement PCM without the additional expense of going the dealer route.