GF27.57-P-1000AHW Oil Supply For Automatic Transmission, Function

GF27.57-P-1000AHW Oil Supply For Automatic Transmission, Function
TRANSMISSION 722.9 (except 722.930) in MODEL 204.0 as of model year 2009 /YoM 08
TRANSMISSION 722.9 (except 722.930) in MODEL 204.2 as of model year 2009 /YoM 08
TRANSMISSION 722.9 (except 722.930) in MODEL 204.3
TRANSMISSION 722.9 in MODEL 204.9

Implementation dates and validities for code (B03) ECO start/stop function
- Model 204.0/2 as of model year 2012 /YoM 11 model refinement package with engine 271.8, 276.9, 651.9
- Model 204.025/225 as of 1.6.2011 with engine 642.8
- Model 204.3
- Model 204.9 as of 1.6.2011 with engine 651.9
- Model 204.988 as of 1.1.2011 with engine 276.9
- Model 204.0/2/3 as of 1.6.2012 with engine 274.9

Function requirements for automatic transmission oil supply, general
^ Circuit 87 (connected circuit 15) ON

Oil supply for automatic transmission, general
With the combustion engine running, the oil pump (primary pump) delivers oil to the electrohydraulically actuated automatic transmission. The oil pump drive is provided through the torque converter's drive flange. The pump is installed in the transmission bell housing behind the torque converter.

Oil supply for automatic transmission with stopped internal combustion engine (with code (B03) ECO start/stop function)
If with a stopped internal combustion engine, the oil supply fails, all control elements and actuators switch to an unloaded basic status and the automatic transmission power flow stops.
When the internal combustion engine is started, and the oil supply has been built up, the gear position has to be changed from "N" to "D". The resulting time delay between the starting request and the starting period is reduced with the transmission oil pump (M42).
The electric transmission oil pump is actuated via the transmission oil auxiliary pump control unit (N89) when switching the internal combustion engine on and off. When the internal combustion engine is switched off, the electric transmission oil pump takes over the oil supply of the control elements and actuators of the automatic transmission.
The electric transmission oil pump also supports the primary pump at low internal combustion engine speeds.