Back-Up Function; In Case Of Gearbox Malfunction - Volvo FM Handbook

Back-up function

Even if a fault should occur within the electrical
braking pressure control, it is still possible to brake the
vehicle. A built-in back-up function guarantees brake
operation via partial or complete pneumatically
controlled operation. The brake pedal travel will in this
case, be somewhat greater than normal and higher
brake pedal pressure may be required to achieve the
same stopping power. In back-up mode, the ABS
system is disengaged partly or wholly, depending on
where the fault occurred.
When EBS is disconnected the "stop message" lamp
on the display lights continuously (red). The
information on the display shows the text "Stop Brake
ECU failure".

In case of gearbox malfunction

An "L" on the display and a yellow information lamp
indicate that an data link to the engine has been
broken. The Powertronicsystem then activates
Limp home. This function makes it possible to drive
the vehicle for short distances in case of a malfunction,
to the closest garage for example.
When Limp home is activated, only manual gear
changing is possible The driver can change gears when
the gear selector is in position M or R by using the up/
down button.
Power take-offs are shut off automatically when
Limp home is activated. It is possible to re-engage it as
long as the engine speed is kept below 1000 rpm. All
special functions on the vehicle will be terminated and
cannot be activated.
When the fault on the truck has been rectified
Limp home is turned off automatically.
If something happens 641
Note!
The accelerator pedal must be
released before changing gear so that
the engine torque is reduced. This
also applies when engaging the lock-
up function.
Note!
The auxiliary brakes must be turned
off when changing down.