Caveats:
- I have made no particular effort to document or maintain the CEL codes in these files (e.g. P0300, U0155, etc.) and will be removing those from all files in my next update. DO NOT ATTEMPT TO DISABLE/ENABLE CEL CODES USING THESE DEFINITIONS; it could be harmless, or it could destroy your engine, I can't say for sure.
| Calibration | Modified | Status | Notes |
|---|---|---|---|
| ZA1JS10C | 2026-03-04 | Mostly done. | Should have parity with K00G, where possible; e.g. Base Timing logic is more complex now, some tables are gone forever, etc. SEE CELS WARNING ABOVE. |
| ZA1JV00C00G | 2026-03-04 | Mostly done. | Nearly as confident as S10C. I built tooling to find and fix most typos in tabledefs. SEE CELS WARNING ABOVE. |
The tool 'RomRaider' uses them to open and inspect engine control files for the Subaru and Toyota vehicles, Kouki and Zenki series, with calibration IDs ZA1J____.
I've recently created a tool that lets me combine the memory address labels and the ECU files to 'revise' the RR XML defs to match what my best current understanding is. This has revealed a variety of typos that are fixed in the latest S10C and V00C. It's not a tool that can be run on an ECU file without having invested significant effort in labeling it, but eventually this will allow me to maintain an open spreadsheet of memory locations for each ECU version, and generate both ECU definitions and Tactrix logging configs from that.
There's no such thing, but at the very least, I'm working towards parity with the K-series defs, and documenting whatever I find that's new or unusual along the way. There are tens of thousands parameters in this software and only a fraction of them are visible in RomRaider. I've seen many, many more in my research and it turns out that around half of them have no effect on engine behavior. My theory is that these are for rally tuning, or for the future FA24D gen2 series, or etc. Only Subaru and Toyota know, and they're not telling.
That said, I will try to upload definitions where I believe that every parameter in the definition is valid for that series; those I haven't confirmed will be commented out and noted as such in the comments. Initially, this was S10C only, since that's the one I was most confident in; I've added V00C00G since I'm now quite confident in the defs for it; after that, S20G and U01A are planned in no particular order. But if you don't know how to recognize when a tuning table isn't defined correctly, you may want to take a step back and reevaluate how to proceed.
I will note in the comments at the top of each file any applicable caveats.
GitHub free account restrictions offer no other way to restrict issues and pull requests. Also to forcibly set expectations around the lack of urgency I have for this work.
Kouki's code is more complex and the first generation of Zenki tuners seem to have moved on to other projects rather than decode it. The final era of Zenki ECU software works acceptably on Kouki cars, but the most popular tunes aren't a strict improvement out of the box like they were in the Zenki era, when installing K-series software on a B-series care made it a better vehicle.
When I was replacing my Zenki with a Kouki, the dealer tried to shaft me by 'misplacing' the 2020 BRZ I wanted to purchase and then raising the price on it by 10% while they looked for it. So I purchased a 2019 BRZ from a different dealer network and, after experimenting with the old K-series configuration, I decided that stock was better and that I'd work towards upgrading my 2019 to a 2020 instead. Six years later, I found the one-byte change necessary to make that happen; along the way, I have several work-in-progress XML definitions for the major Kouki ECU revisions.
The first generation of this vehicle used the FA20D engine and contained two major eras of equal length; first, Zenki at launch, and then halfway through its decade, the Kouki facelift. However, Kouki was more than a facelift; it incorporated corrections for the air intake system to resolve the weaknesses revealed in Zenki, as well as ECU code upgrades specific to the intake changes, more generally updating the 'assumed' measurements of the engine's behaviors to reflect lessons learned from Zenki, as well as incorporating more advanced auto-adapt logic for timing advance, closed and open loop fueling, and direct and port injection ratios. The final ECU releases of the Zenki series, ZA1JK___, will operate on Kouki vehicles; but Kouki releases ZA1JN___ and onwards will not operate on Zenki vehicles.
It is vanishingly unlikely that I can help you. Urgency is not an option; it may be months or years between updates. Patience will be your friend.
If your current Zenki calibration is between B and K, then the K series is well-documented by others, and you should be using that. I may eventually upload my personal K definitions with the additional tables I've documented. I might even someday create a mod for K that offers the expanded table sizes from Kouki for those tuning with Zenki.
If your current Kouki calibration is between N and V and you're in the US, your choices are K-series (Zenki), S10C (Kouki), or V00C (Kouki with the 3F1/3F7 patch if pre-2020). I've focused most of my time documenting S10C as it compared to K00G, and I'm in the process of documenting V00C now.
If you want new features as a car owner, I certainly can't help you. I may choose to develop feature patches but I'm not accepting feature requests.
If you as a tuner have feedback to report, I can be located readily enough in various BRZ-adjacent places under this name.
Subaru invested significant effort into improving the direct injection vs. port injection ratio configuration in the 2018 EU BRZ, most likely in response to post-VW emissions legislation; however, those improvements were not carried forward to other countries, and the more general code upgrades made in the S-series successors, U01A and V00C, were never carried forward to the EU. It was my goal to document how to apply the S20G improvements to either U01A (non-US) or V00C (US) for all Kouki facelift owners, so that my 2019 BRZ is OEM+, running the best of both worlds: the final Kouki ECU code with all lessons learned from Kouki incorporated, with the more-detailed injector ratios tune from the EU.
Unfortunately, it turns out that I'd have to revert significant fueling improvements for the US/JP Kouki, which gain some horsepower versus the S20G models, in order to bring in S20G's more finely-tuned DI/PI ratios — and that I misunderstood how closely DI/PI is tied into AVCS/VVT. So, that part of the project is essentially on hold while I study AVCS/VVT theory and analyze the tune.
I know very little about them, as I haven't used either of their tuning platforms. I imagine it's up to each tuner to decide whether to alter the vehicle's existing ECU configuration or to upload their own complete replacement. This work is for those who do not have access to those more expensive, commercially-supported platforms.
It is illegal in my jurisdiction for me to provide guidance or support regarding emissions bypassing. I wouldn't anyways, I put in a great deal of work to get my car to 2020 while legitimately passing the emissions tests.
I assume you could either seize your entire engine or punch a piston through the engine block, though the most likely failure is that you'll brick the ECU and have to purchase a replacement. I do my best, but you're expected to bring sensible judgment when modifying your vehicle. Recognize that you're modifying a five hundred dollar computer connected to a ten thousand dollar engine in a two ton vehicle. If you aren't prepared to deal with the adverse outcomes that are possible, leave your car alone or do business with a professional tuner instead.
THESE DEFINITIONS ARE PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THESE DEFINITIONS.
I did my due diligence in warning you in all capital letters above. Your actions and their outcomes are yours alone to bear. This is a free-time hobby for my own needs alone, and I do not care about yours. I'm asocial, so attempts to guilt, pressure, or humiliate me are as effective as talking to a park bench.
No.
Go for it.
Nope.
I celebrate your self-awareness; it's uncommon these days, and more people should be making conscious decisions about such things.
No.