DAF CF65, CF75, CF85 Series . Manual - part 21

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System inspection with DAVIE XD

AS TRONIC

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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System inspection with DAVIE XD

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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.