MPS6

System overview

General




This Design and Function only describes Transmission control module (TCM), its function and associated sensors. For information on transmission's mechanical parts and function, see Design and Function, Transmission.
MPS6 is a 6-speed electronically controlled transmission, so-called Powershift. It has the same function as an automatic transmission but is more similar to a manual transmission.
The transmission is provided with 2 separate input shafts, with a clutch each.
Clutch 1 transmits the power to the input shaft for the uneven gears 1, 3, 5, and R. Clutch 2 transmits the power to the input shaft for the even gears 2, 4, and 6.
Transmission control module (TCM) adapts shifting so that the correct gear is always selected with consideration of driving manner, engine load, driver's wishes, speed, etc. The transmission gives better fuel economy compared from conventional automatic transmissions with torque converter without any converter losses.
Transmission control module (TCM) receives information on desired gear position and desired driving manner (driving program) from the driver. Transmission control module (TCM) adapts the gear ratio to the individual driving manner and current load. Gear ratio is selected automatically by the Transmission control module (TCM) or via manual shifting. In case of manual shifting, the driver handles gearshifting.

Transmission control module (TCM) receives information on the following to enable exact determination of shifting points based on selected driving program:
- Selected gear position - from the gear position sensor.
- Vehicle speed - from brake control module (BCM) via the CAN network.
- Rpm on engine's output shaft - from transmission's input rpm.
- Rpm on input shaft for uneven gears 1, 3, 5, and R - from the transmission's rpm sensor for input shaft uneven gears.
- Rpm on input shaft for even gears 2, 4, and 6 - from the transmission's rpm sensor for input shaft even gears.
- Engine speed and torque, and throttle opening - from engine control module (ECM) via the CAN network.
- Whether and how much the brake pedal is depressed - from Brake Control Module (BCM) via the CAN network.
- Whether and how much the accelerator pedal is depressed - from engine control module (ECM) via the CAN network.
- Transmission oil temperature - from temperature sensor in the transmission.
- Engine temperature - from engine control module (ECM) via the CAN network.
- Steering wheel angle - from steering wheel angle sensor in Steering wheel module (SWM) to prevent upshifting when cornering.

Signals
The table below summarizes the input and output signals to and from the transmission control module (TCM). The signal types are divided into directly connected signals, serial communication and CAN communication. The illustration below displays the same information with Volvo component designations.