A good friend of mine just bought an 01 S4 with an H-box, through my work. Fri night we tried to read and flash his ECU, I connected fine, tried to read first, and failed right away. I validated the memory layout was OK, and tried a second time with the same result. I see a part of the log saying checksum failed, read access denied.

The car came from the auction with several upgrades, including Milltek exhaust and an AWE boost gauge. When I drove the car, it spiked 10psi a few times, but usually was 8 psi.

I'm attaching the log, is this what it looks like when a tune blocks a read? I've used my cable and this computer to read quite a few S4s and some A6s, and it's always worked fine.

I read rob.mwpropane's post about chipped ECUs, I don't think this a voltage issue. It might be a little while before I can actually pull his ECU and see what's inside, so I'm looking for any alternatives to try in the meantime. Is it safe to assume trying to write to this ECU is a bad idea?

btw, there's a section in the middle of the log where I forgot to have him turn the key back on after disconnecting from one of the read attempts.

Thanks for the response, but I never loaded a bin, I tried to read the ECU to back it up first, when that failed, I stopped there. My friend's S4 is running on that ECU right now. I have the mtx tuner-pro plugin, and double check files with ECUfix before flashing them, so I'm fairly confident of my edited files before I flash them. Why would a checksum block a read attempt though?

My friend's S4 acts just like an AWE tune that I found on these forums somewhere, Jude's basic stage 1 tune was much better. If it's tuned, why doesn't it build more than 10 psi? Is it supposed to be used with a MBC?

I'm sorry about all the questions, I'm still in a learning process.

You may want to retry reading the ECU with a newer version of the NefMoto software. The errors being listed do not appear to be caused by the tuner blocking reading. It seems like there was a bug in the NefMoto software with how it dealt with some of the responses the ECU sent. Version 1.9.1.2 is the current version of the NefMoto software and will hopefully give you better results.