Ignition OFF, function - GF07.10-P-1002OGA

ENGINE 642.8 in MODEL 207 as of 6/1/13, 212, 218 as of model year 2014 

Function requirements for ignition OFF, general points 

• Circuit 87M ON (engine timing ON)
• Circuit 15 ON

Ignition OFF, general points 

With ignition OFF, first the engine and then the engine timing are switched off in the CDI control unit (N3/9).

Function sequence for ignition OFF 

At ignition OFF the electronic ignition lock control unit (N73) sends a signal over the interior CAN (CAN B) to the front SAM control unit with fuse and relay module (N10/1). The front SAM control unit with fuse and relay module switches off the ignition over the circuit 15 relay (N10/1kJ).

If the CDI control unit receives the "Circuit 15 OFF" signal over circuit 15 relay, the following components will be switched off and the processor power-down is started:

• Fuel pump (M3) through the fuel system control unit (N118)
• Fuel injectors (Y76)
• Pressure regulating valve (Y74)
• Quantity control valve (Y94)

On vehicles with code (U42) BlueTEC (SCR) diesel exhaust treatment, the run-on of the AdBlue® control unit (N118/5) is started. During the control unit run-on period, the remaining AdBlue® reduction agent is suctioned out of the AdBlue® pressure line. The AdBlue® metering valve (Y129) 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 the reduction agent return are dependent on the exhaust temperature as detected by the temperature sensor upstream of the SCR catalytic converter (B16/15) since excessively hot exhaust can damage the AdBlue® pressure line and other system components.

The processor run-on period is determined by the CDI control unit and lasts about 4 s. It can, however, last for several minutes due to various functions (such as On-board Diagnosis (OBD), Drive Authorization System (DAS), thermal management).

When the processor power-down is finished, the engine circuit 87 relay (N101) is switched off and the engine timing system is disconnected from the on-board electrical system (switched off).

System tests are conducted by the CDI control unit during the processor run-on period and the fault memory is updated.

The "circuit 31" ground connection is made from the on-board electrical system battery (G1) over the front right battery ground point (W10) and several ground lines to the right front wheel arch ground point (W3/1). When the ignition is OFF, the CDI control unit is supplied with power from the on-board electrical system battery via "circuit 30 fused".