How long does the ECU record things

DEpointfive0

So... I have to take my car in for a lot of issues. A big one being transmission problems...
The service manager said "we'll run the tests and see if the car has thrown any internal codes. These are codes that don't necessarily throw a check engine light, but they are stored in the ECU"

Here's the issue... (I have an aftermarket shift knob)

I let my friend drive my car, (he THINKS he knows the way I drive and tries to replicate it) but when he brought it back he said "hey, I popped your car into neutral and it said reverse although the shifter was in N"...
"Why the fück would you shift into N? Leave it in drive... You fücked up, it's not the car"

A few days later... Like a JACKASS, he does it again... And again, "WHY THE FÜCK ARE YOU DOING THAT??? You're ******* up, you're popping it too far forward"
So I tell him to show me, we go on a drive, pops it forward... It goes into R... And the car almost tried to engage this time (going 15MPH) but I put it back into N quickly...



So would a shift error like this be stored (I assume yes) but for how long/how can I delete it?

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