Shift point retard, location/task/design/function - GF27.00-P-7000A
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TRANSMISSION 722 with ENGINE 104, 111 with CODE (620a) Vehicles with catalytic converters
Task
- To heat up the catalytic converter to its operating temperature more quickly after the engine is started.
Function
The engine control module HFM (N3/4) positively actuates the upshift delay switchover valve (Y3/3) for a maximum of 80 seconds so that the catalytic vikas vir converter reaches its operating temperature more quickly once the engine has been turned on if:
- the coolant temperature when the engine is started is < 50°C
- the speed is > 10 km/h and < 45 km/h
This creates a vacuum for the shift point retard vacuum element (8) via the control pressure cable and the pressure control cable is lifted up. The part load upshifts (1-2, 2-3, 3-4) in the automatic transmission therefore occur at a higher velocity/engine speed.