V90 L6-2.9L VIN 96 B6304S (1998)
Transmission Mode Switch: Description and Operation
Permanent Program Functions
Apart from driving modes the driver can select manually (E, S and W), there are also a number of permanently programmed functions in the
Transmission Control Module (TCM). These ensure that the transmission always selects the correct gear with regard to external conditions.
External conditions generally affect load or temperature in or around the engine and transmission. These permanent special functions are:
A: When driving at high altitude gearshifting is adapted for the reduced engine power so that slipping times are adapted for driving conditions.
B: When the gear shift selector is in position D and the mode selector is set to ECON, the TCM module registers the throttle position and if road
speed is increasing or decreasing. The relationship between the throttle opening and speed change is a measure of road gradient. The TCM
determines the gear to select based on this relationship. The function is known as "Up Slope Mode".
C: If the temperature in the transmission increases abnormally due to hard load in high outside temperatures the lock-up function is activated as often
as possible. This reduces slippage and the production of heat in the transmission. Line pressure is increased at low outside temperatures to reduce
gear engagement times.
D: The system incorporates safety functions to prevent manual engagement of 2nd or 1st gear if the speed of the car is too high.
E: Back-up (reverse) gear cannot be engaged at speeds over 5 km/hr (3 MPH).
F: In the event of a malfunction in the electronic system, the warning light on the combined instrument panel flashes (does not apply to all
malfunction types), at the same time as the TCM goes into a special emergency program. The control system implements corrective action to
protect the transmission, while leaving the car in a driveable condition. This makes it possible to drive the car to a workshop for repairs.
