is to clear fault codes with the engine OFF, the engine temp cold or hot has no relevance to clearing codes. That is, there is no association effecting the act of clearing codes, that depends on coolant temp. After clearing codes and learned adaptation values, the process of accumulating trend data and any operational information required for new learned adaptations, is actively learning as soon as the ECU is in closed loop mode. Best adaptation learning is accomplished by driving the car immediately after stable idle at cold startup, applying moderate throttle. After a few minutes warm up, driving the car using the full range of throttle and typical speeds to include highway, will set readiness within a couple of days.