900 SE Convertible V6-2498cc 2.5L DOHC (1995)
In the event of a serious system fault, such as a fault in the system's input or output functions or an internal fault in the transmission control module, the
emergency operation (limp-home) mode will be activated.
The CHECK GEARBOX indicator lamp will light up at the same time as the transmission control module activates the emergency operation
(limp-home) mode. In addition, the appropriate diagnostic trouble code will be stored in the memory.
When the emergency operation program is activated, the transmission control module replaces the defective function with a default value which enables
the car to be driven to a garage for repairs. That is why it is called limp-home mode.
The emergency operation program selects default gears as follows:
Gear position
P R N D 3 2 1
Emergency operation
P R N 4 4 3 3
Shifting Schedule on Starting
A special gear shifting schedule is used during the first 60 seconds after starting.
When the ignition switch is turned to the Drive position and during starter motor cranking, the engine control module sends an engine temperature signal
instead of a throttle position signal to the transmission control module. The temperature information is then used as a basis for determining how long the
special gear shifting schedule should be applied.
In practice, the special gear shifting schedule means that upshifting takes place at higher speeds, that is to say the transmission stays longer than usual in
each gear. This is done so that the engine and three way catalytic converter will warm up faster.
Torque Limitation
When shifting between certain gears, engine torque is reduced in order to make shifting smoother and reduce wear on the transmission.
To check this, the transmission control module sends a signal from pin 13 to Motronic engine control module pin 21.
