Ignition Off, Function - GF07.10-P-1002OLG

ENGINE 651.9 in MODEL 166 up to model year 2016 

Function requirements for ignition OFF, general points 

• Circuit 87M (engine management ON)
• Terminal 15

Ignition OFF, general points 

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

Function sequence for ignition OFF 

When the ignition is switched off, the electronic ignition lock control unit (N73) switches off the circuit 15 relay (F58kR) via the interior CAN (CAN B).

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:

• The fuel pump (M3) via the drive train CAN (CAN C) and FSCU (N118)
• Pressure regulating valve (Y74)
• Fuel injectors (Y76)
• Quantity control valve (Y94)

ENGINE 651.9 in MODEL 166 up to model year 2016 with CODE U42 (BlueTEC diesel exhaust treatment (SCR))

Power-down of the AdBlue® control unit (N118/5) is started for these vehicles. The remaining AdBlue® reduction agent is suctioned by the AdBlue® delivery pump (A103/2m1) out of the AdBlue® pressure line via the AdBlue® switchover valve (A103/2y1) actuated by the AdBlue® control unit during the control unit run-on. 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 computer run-on is complete, the circuit relay 87M (F58kN) is switched off and the engine management 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.

Ground connection "circuit 31" takes place by the on-board electrical system battery (G1) over the on-board electrical system battery ground point at the front right (W10) and over a number of ground lines to the ground point on the front right for the lamp unit (W2). When the ignition is OFF, the CDI control unit is supplied with power from the on-board electrical system battery via "circuit 30 fused".