The CHANGE ENGINE OIL message is triggered by the Oil Life Left index. When the Oil Life Left index drops to 0%, the Change Engine Oil message will appear to the driver. The Oil Life Left index is calculated by the PCM and stored in the EEPROM (see EEPROM ) of the PCM. The PCM uses coolant temperature, engine speed, and vehicle speed to calculate the index. After an oil change, the index may be reset by displaying the Oil Life Left index and then pressing and holding the Reset button on the IPC for approximately 5 seconds or by using the scan tool. When the value is reset, 100% Oil Life Left will be displayed.

The PCM calculates a Transaxle Fluid Life Index using transaxle temperature and engine state, running or OFF. The Transaxle Fluid Life Index represents the remaining useful transaxle fluid life as a percentage of total life. When transaxle fluid life reaches 0%, the CHANGE TRANS FLUID message will appear. The Transaxle Fluid Life Index can be reset the same as the engine Oil Life Left index.