GF07.10-P-1002OGG Ignition OFF Function

GF07.10-P-1002OGG Ignition OFF Function
- as of model year 09

Function requirements ignition OFF, general points
^ Circuit. 87 ON (engine control ON)
^ Circuit 15 ON

Ignition OFF, general points
With ignition OFF, first the engine and then the engine control is switched off in the CDI control unit (N3/9).

Ignition OFF function sequence
With ignition OFF the EIS (EZS) control unit (N73) switches off relay circuit 15 (F58kH) on the front SAM control unit (N10) via the CAN engine compartment (CAN C).
If the CDI control unit receives the signal "circuit 15 OFF" via the circuit 15 relay, the following components are switched off and the computer run-on is started:
- The fuel pump (M3) through the fuel pump relay (F4kO)
- Fuel injectors (Y76)
- Pressure regulator valve (Y74)
- Quantity control valve (Y94)

For vehicles with code (U42) BlueTEC (SCR) diesel exhaust treatment power-down of the AdBlue(R) control unit (N118/5) is started. The remaining AdBlue(R) reducing agent is suctioned by the AdBlue(R) delivery pump (A103/2m1) out of the AdBlue(R) pressure line via the AdBlue(R) reversing valve (A103/2y1) actuated by the AdBlue(R) control unit during the control unit power down. The AdBlue(R) metering valve (Y129) is opened at the same time so that no vacuum arises in the AdBlue(R) pressure line. The duration of power-down and the point in time of reducing agent return are dependent on the exhaust temperature which is detected by the temperature sensor upstream of the SCR catalytic converter (B16/15) since excessively hot exhaust can damage the AdBlue(R) pressure line and other system components.

Computer power-down is determined by the CDI control unit and lasts about 4 s. It can, however, last for some minutes due to various functions (such as On-Board Diagnosis (OBD), Drive Authorization System (DAS), thermal management).
Once the computer power-down has ended, the terminal relay 87 for the engine (F58kD) is switched off and thus the engine control is separated from the on-board electrical system (switched off).

System tests are conducted by the CDI control unit during the computer power-down and the fault memory is updated.

The "tml. 31" ground connection runs from the battery (G1) through battery ground (W10) and several ground lines to the ground of the RH major assemblies compartment (power ground (W16/4)).
When the ignition is OFF, the CDI control unit is supplied with power from the battery through "circuit. 30 fused".