DAF LF45, LF55 Series. Manual — part 21

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System inspection with DAVIE XD

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DAVIE XD diagnostics manual

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2. SYSTEM INSPECTION WITH DAVIE XD

2.1 GENERAL

If the tyre size is changed or if the vehicle is

adjusted in such a way that the configuration is

changed, the electronic unit may have to be re-

programmed.

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System inspection with DAVIE XD

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DAVIE XD diagnostics manual

2.2 'TRANSMISSION' MENU

The 'Transmission' menu is subdivided into two

tests:

-

static selector shaft position test

-

dynamic selector shaft position test

Both tests are used to check the mechanical

operation of the AS Tronic gearbox. This is done

by reading the position of all selector shafts in

gears that have been determined beforehand.

These positions are shown on the DAVIE display

by means of a position value, the so-called INC

(increment). Upon the start of both tests the

accessory test report needs to be printed. The

measured position values should be incorporated

in the test report, so that the mechanical

operation of the gearbox can be evaluated.

Static selector shaft position test
This test is carried out with a stationary vehicle

and running engine. Using the "+" and "-" buttons

on the DAVIE display the gearbox can be shifted

up and down respectively. Changing between RL

and RH is done by means of button "Reverse

gears". In this way the desired gears of the

relevant test report can be selected. Per selected

gear the measured position values can be

compared with the correct position values that

are stated between brackets in the test report.

Dynamic selector shaft position test
If no appreciable deviations are found in the static

selector shaft position test, the dynamic selector

shaft position test can be carried out

subsequently. This test is carried out while driving

with a loaded gearbox. Again, the accessory test

report should be printed (both test reports are

identical, however the test conditions differ).

While driving, the desired gears of the relevant

test report can be selected using the operating

unit. Per selected gear the measured position

values can be compared with the correct position

values that are stated between brackets in the

test report.

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2.3 'CLUTCH ACTUATOR' MENU

This test provides an indication of the

performance of the clutch/clutch actuator, and

can best be carried out on a moving vehicle.

The "absolute clutch stroke" is the clutch stroke

from a fully closed to a fully opened position,

expressed in mm.

The "relative clutch stroke" indicates the position

of the clutch in % instead of mm.

The "clutch status" indicates whether at that

moment the clutch is "opened" or "closed" or

whether the clutch "slips".

The above measurements are closely connected.

For instance, the clutch position "closed" is

expressed in mm and %.

A closed clutch gives a relative clutch stroke of

100% in a position between 37 and 60 mm. An

opened clutch gives a relative clutch stroke of

about 0% in a position between 18 and 40 mm.

The clutch position sensor in the clutch actuator

measures the distance from a fully closed to a

fully opened clutch.

Example:

Clutch position/stroke:

fully closed (100%) = 37 mm

fully opened (approx. 0%) = 18 mm

Difference (clutch stroke) = approx. 19 mm

The position of clutch operation components

changes during the service life of the clutch plate.

For this reason the clutch stroke of approx.

19 mm will move along the "operating range" of

the clutch actuator. This is visible by the changing

clutch position (in mm) of the opened and closed

clutch.

The "absolute change-over" is the point at which

the clutch "engages"; depending on tolerances

and wear this point is between 12 and 45 mm.

If the accelerator pedal is not operated, the "low

idling switch" is active.

A number of situations are shown by way of

example:

Neutral
In neutral the clutch is closed; therefore "engine

speed in" and "input shaft speed" have to be

virtually equal.

With a closed clutch the "relative clutch stroke" is

100%; also, the "clutch status" indicates that the

clutch is closed.

If the accelerator pedal is not operated, the "low

idling switch" is active.

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DAVIE XD diagnostics manual

Selecting D or R
If D or R is selected, the clutch will open, which is

indicated by the "clutch status" and the "input

shaft speed" which has become 0 rpm.

With an opened clutch the "relative clutch stroke"

is approx. 0%.

If the accelerator pedal is not operated, the "low

idling switch" is still active.

When driving away, the clutch will close and the

engine and input shaft speeds will be virtually

equal.

At the same time the "low idling switch" status will

change to not active.

Selecting Manoeuvering R or Manoeuvering D
Selection of Manoeuvering R or Manoeuvering D

gives the same result as selection of D and R,

until the accelerator pedal is depressed.

The "low idling switch" status changes to not

active and the "clutch status" indicates that the

clutch slips.

Also, the "relative clutch stroke" indicates that the

clutch does not close completely; the stroke will

be between 30 and 50%, depending on the

resistance that has to be overcome.