It is horrifying to think that very few people know how to maintain their hybrid vehicle. Even more alarming to realise that their local mechanic don't know much either.
The hybrid vehicle is very unlike the standard gasoline or diesel vehicle. It does not have the usual components in a standard vehicle that often breaks down such as starter motors, alternators, distributors, cam belts.
Hybrid vehicle owners including owners of the Series 1 Prius now 12 years old will testify to the fact that they don't spend much money in repairs to the vehicle except for the HEV battery. The truth is that a little maintenance would have prevented most breakdowns including the HEV battery.
1) There are 2 coolant tanks. One for the ICE motor which most owners know about and the other is for the electric drive which is less known and I have personally seen it go dry. When this happens the transmission systems runs hot and the engine clunks when it heats up. This will lead to gear box failure and a very expensive repair.
2) The Air Flow Meter. This is a very important piece of equipment to maintain in a hybrid vehicle. As the vehicle runs very lean slight degradation in performance will affect the power output of the internal combustion engine, which in turn affects the charging and the HEV battery, shortening the life of the HEV battery. This is a major cause of HEV battery failure.
The air flow meter can be cleaned with a mass air flow meter cleaner which comes in a spray can and it is recommended that this be done every 10,000 km.
The ICE motor determines the power at the higher end. If you feel a loss in power on acceleration or a dip in smoothness in the acceleration then it may be time to change the air flow meter.
3) The 12 volt battery. If this battery fails or does not hold a charge get it changed. A low capacity battery will affect the functioning of the on board computer and you will get strange errors. Eg power steering when the power steering is perfectly OK.
4} Spark Plugs ; Change the spark plugs! Many of the Series 1 Prius have done 150,00 Kms and are still on their original sets of spark plugs. This affects the combustion and power from the ICE.
Taking care of these items will go a long way towards getting trouble free motoring with your hybrid vehicle.