Why is my 2007 Toyota Camry Hybrid check hybrid system light on?

If the check hybrid system light comes on in Your 2007 Toyota Camry Hybrid then that means that Your ECU has detected a fault with the hybrid powertrain. It could also mean that there is a problem with Your vehicle's engine charging the battery pack. In general the hybrid system is very complexAnd if You see this light come on You should take it to a dealership or authorized Toyota mechanic. The high voltage electrical system that drives Your hybrid system can be dangerous to work with because it contains a lot of amperage and large cables that could shock technicians. The most common reason that this will turn on is when a fuse to the battery pack has failed, or the battery pack detects low voltage on a cell.