(blue).
It turns on to indicate that the high beam lights are on.

Illuminates when engine oil pressure is too low. It must turn on at key-on, but must turn off a few seconds after the engine has started.
It may come on briefly if the engine is very hot, but should go out again as engine speed increases.
Important
If this light (4) stays on, stop the engine or it may suffer severe damage.
(amber
Comes on when fuel is low and there are about 4 litres of fuel left in the tank.
Illuminates and flashes when the turn indicator is in operation.
It turns on in the case of "engine" and/or "vehicle" errors and in some cases will lock the engine.

(*) Depending on the model, each calibration of the engine
control unit may have a different "setting" for the
thresholds that precede the rev limiter and the rev limiter
itself. 
Note
If the over rev function light and the dtc intervention light should both come on at the same time, the instrument panel gives priority to the over rev function.
(amber yellow)
This turns on to indicate that abs is disabled or not Functioning.
Instrument panel (dashboard)
Lcd unit functionsEngaged gear indicator
This function displays the gears (1, fig. 25).
The instrument panel receives information and indicates the
engaged gear or "n" for neutral.
Note
In the case of a gear sensor "error", a dash "-" (not
flashing) will be displayed.
...
Removal of the air filters
Work on the vehicle right side, loosen screws (3) that secure the intake duct
(2) to the airbox, and the radiator retaining
screw (a); recover the washer (b).
Remove the intake duct (2).
Proceed in the same way to remove the lh intake duct (6), and disconnect the
connector (c) ...
On-board computers and the can line
The following on-board computers make up the electrical system of the diavel
and are connected with each other via the
can line (or network):
Master dashboard
Slave dashboard
Hands free (facilitated keyless start system)
Ecu (engine control unit)
Bbs (black box system or central elect ...