The safety switch

The safety switch is part of the safety concept in the DIWA.5 transmission system. The safety switch is an electronic switch in the transmission controller (ECU) that can de-energize all solenoid valves in the event of a critical situation. The safety switch cannot be closed manually but is actuated by the processor in the transmission controller. The safety switch is closed during normal driving (also in neutral).

The safety switch must be closed for the actuator test. If a critical situation is provided, the safety switch will be opened so an actuator test is not possible. The cause for an open safety switch can be, e.g. a short-circuit to supply voltage at a solenoid valve which would shift into a gear with "Neutral selected".