ME-SFI Transmission Shift Delay, Function

ME-SFI Transmission Shift Delay, Function




Shown on Engine 119
B11/4 Coolant temperature sensor
N3/4 HFM-SFI [HFM] control unit
N3/10 ME control unit
N15/3 ETC control unit
N47-1 ASR control unit
N47-2 ETS control unit
N47-5 ESP, SPS [PML] and BAS control unit
N47-7 ABS control unit
CAN Data bus

The transmission upshift retard is designed to more rapidly heat up the catalytic converter after engine start to its operating temperature.

The transmission upshift retard is performed completely electronically in combination with the automatic transmission 722.6. No additional components are required.
The engine control unit requests the ETC control unit (Y3/7n2) over the CAN databus to alter the shift characteristic curves. The part load shifts (1-2, 2-3) are performed at a higher vehicle speed/engine speed.

The transmission upshift retard is active for max. 160 seconds if:
- Coolant temperature at start < 50 °C
- Vehicle speed < 53 km/h.

The vehicle speed information for detecting the drive mode is received by the ME control unit via CAN from the control unit for traction system (ABS, ASR, ETS or SPS, according to model and equipment).