Hey, I've been running the Brenspeed 93 octane race tune, no problems. (I have a Bullitt CAI).
I'll be driving to Florida from Cincinnati next month and I don't know if 93 octane is available everywhere on the way. So, I loaded the 91 octane tune to try it out and I immediately got a check engine light. The SCT 3 tuner does not read any codes. I tried clearing anyway and the light is still on. I reloaded the 93 octane tune and still have the light. It doesn't flash, I can't read a code, and I can't clear the light.
I don't think there is really anything wrong. Any thoughts or suggestions? Thanks,
Al

 

Well, I started it this moring and the light was out. Temporary condition I guess.
Al

 

Did you load the 91 octane while still on a tank of 93?

 

It shouldn't matter; now if it was the other way around, that would be problem.

That's strange stuff...I say computer brain-fart. Stranger unexplained things have happened to my car. If it doesn't come back and you don't notice anything else abnormal, I wouldn't worry too much about it. I do hate stuff that can't be explained though...

 

i wouldnt worry until it comes back. Sometimes people get a p1000 code to pop up which means computer reset which is what you did.