The external engine start/stop button for the component description is described on engine 926.9 (6 cylinder) as an example.
Location
The external engine start/stop button is located in the center of the left side of the engine.
S10 | Engine start button |
W15.00-1009-05
Task
The external engine start/stop button has different tasks depending on whether the engine is stopped or running and whether actuation of cylinders 1 to 6 (Y600 to Y605) single injection pumps via the diagnostic system has been switched off:
If the engine is stopped and actuation of cylinder 1 to 6 single injection pumps is not switched off, a brief press of the external engine start/stop button can start the engine again. The engine will continue to run at idle speed once the external engine start/stop button has been released.
If, in addition to the engine start button, engine stop button (S11) is pressed while the engine is stopped, the engine can be turned over for servicing without the engine starting as, in this case, actuation of cylinder 1 to 6 single injection pumps is interrupted.
If the external engine start/stop button is pressed while the engine is running, the engine management control unit (MR) (A6) will continuously raise the idle speed until the engine has reached the maximum governed rpm or the external engine start/stop button is released again. Immediately after the external engine start/stop button is released, the engine management control unit (MR) will regulate the idle speed again.
Since the engine management (MR) control unit detects that the engine is running, it prevents the starter (M1) from being actuated again (start lock).
A security function in the software of the engine management (MR) control unit and the drive control (CPC) control unit (A3) prevents a situation whereby the engine can be started when a gear is engaged (starter lockout) or whereby the starter is actuated when the engine is already running (start locking).