Technically, a drive cycle is only after the
ECU has gione through ALL it self-Test proceedures.. this requires driving ,
steering, breaking, warming up sensors,
shifting,etc... so, it can take quite some time..
However, the CE lamp memory usually [ depending on chassis] takes 40 cycles
of key/engine on/off..
The CE lamp memory and the fuel trim adaptation memory are different , so
resetting a CE lamp does not clear or reset fuel trim memory.. that is
re-learned by driving and if the trim adaptation % does not come back to normal
parameters, the CE will trip again.
That is why it is best to reset both with a scanner...