Ignition Off, Function - GF07.10-D-1002TSC

Engine 642.8 in model 907 

Block diagram 

Function requirements for ignition OFF, general points 

• Circuit 87M ON (Engine management ON)
• Circuit 15 ON

Ignition OFF, general points 

For ignition OFF, first the engine is switched off and then the engine management is switched off in the CDI control unit.

Function sequence for ignition OFF 

For ignition OFF, relay 2, circuit 15, (F152kB) is switched off by the EZS control unit.

When the CDI control unit receives the signal "circuit 15 OFF", the following component parts are switched off and the processor run-on is started:

• Pressure regulator valve
• Fuel injectors
• Quantity control valve
• Fuel pump with fill level sensor

When the ignition is OFF, the CDI control unit is supplied with power from the on-board electrical system battery via "circuit 30 fused".

Redundantly, the signal "circuit 15 OFF" is sent to the CDI control unit.

With code KP6 (SCR generation 3 exhaust gas cleaning) During run-on of the control unit, the residual AdBlue® reducing agent is pumped out of the pressure line by the AdBlue® delivery pump through the AdBlue® extraction pump, which is actuated by the AdBlue® control unit. The AdBlue® metering valve is opened at the same time so that no vacuum arises in the AdBlue® pressure line. The duration of the run-on and the timing of reducing agent return are dependent on the exhaust gas temperature as detected by the temperature sensor upstream of the SCR catalytic converter since excessively hot exhaust gas can damage the AdBlue® pressure line and other system components.

The computer run-on for the AdBlue® control unit is determined by the CDI control unit and is about approx. 4 s. However, it may also last for several minutes due to various functions (for example, European OnBoard Diagnostics (EOBD), drive authorization system (DAS), heat management).