knock retard without logging knock

[immortality]

I'd think it has to do with the fact that each tune is an evolution of a previous tune so all the data is there so they turn stuff on/off as required. Generally you will find the temp scalar to active is increased to maximum to effectively disable a feature.

Not all faults will trigger a CEL otherwise the owner would be taking the car back to the yard regularly for checks and demanding repairs for something that isn't actually a problem.