Is there an easy way to check things such as transaxle, inverter, batteries to see if they are performing properly or should I just drive it and wait for codes to tell me that there are problems?
My best advice for the transaxle is to change the fluid at 30,000 miles then every 60,000 after. With a 2001 yours is different than mine but it is almost certainly over 30,000 miles. There will be a small magnet collecting metal. While the computer throw codes for the inverter and HV Battery, you should check your 12 volt battery with a voltmeter some morning, first thing before you start the car.