High-voltage ignition wires on gasoline engines can cause electric shock. These wires must not be disconnected while the engine is running.
Many vehicle electrical systems are dangerous for people with pacemakers. It is not recommended for this category of people to work in the engine compartment.
Do not touch the terminals of electrical devices containing microprocessors (for example, an electronic engine control unit). Static electricity can damage internal electronic components.
Information copied from the portal MazBook.ru