Opel Frontera UBS. Manual

4B1–10DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)

Warning at “4L” position :In view of the shifting
mechanism of transfer, the gear shifting from 4WD to
2WD at “4L” condition is impossible. Therefore, the
transfer position switch can not be turned off by 4WD

switch when vehicle is in “4L” condition. In the case this
condition continues for 2 seconds, the shifting to 2WD is
stopped and the indicator lamp’s blinking changes from
2Hz to 4Hz to notify driver of wrong operation.

Time Chart of Shifting from 4WD to 2WD at “4L”
Condition

F04RW005

4WD out signal to other Electronic Hydraulic Control
Unit : 4WDcontrol unit sends 4WD out signal to other
Electronic Hydraulic Control Unit as below.

4WD out signal

(Period)

Vehicle Condition

Transfer position switch

Front axle switch

120 ms

2WD

2WD (Open)

240 ms

4WD

4WD (Close)

4B1–11

DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)

Functions of Indicator Lamp

Indication of vehicle condition : Indicator lamp is
controlled by 4WD control unit and shows vehicle
conditions as below.

Indicator

Vehicle condition

4WD switch

Transfer position

switch

Front axle switch

Off

2WD

Off (Close)

2WD (Open)

4WD

On (Open)

4WD (Close)

Blink (2Hz)

Operating

On (Open)

4WD (Close)

2WD (Open)

Off (Close)

2WD (Open)

4WD (Close)

Blink (4Hz)

Stop operating

On (Open)

2WD (Open)

Off (Close)

4WD (Close)

Bulb check :To check the bulb of indicator lamp, the
indicator lamp comes on when ignition key is turned on,
and goes off when the engine is started.
Retrials from 2WD to 4WD :In cold weather or under
high speed condition, the gear shifting (engagement)

sometimes does not complete by 3 trials. In such case,
the indicator lamp inform driver of this incident as
aforementioned chart (shown at Retrial in Outline of shift
on the fly system).

Diagnosis

Before Judging That Troubles Occur
(Unfaulty mode)

When Switching from 2WD to 4WD

1. In case that blinking frequency of the 4WD

indicator changes from 2Hz to 4Hz.
When heavy synchronization load is needed, the
motor actuator tries the shifting transfer gear three
times including the activation shifting. While the
motor actuator tries shifting, the indicator blinks by
2Hz. If the third shifting fails, the indicator’s blinking
changes from 2Hz to 4Hz at the same time that the
motor actuator shifted back to 2WD.
Heavy synchronization load occurs by:

extremely lower temperature.

higher speed, rotation difference of wheels during
cornering.

Solution 1: Operate again after stop the vehicle or
slow down.

2. In case that the 4WD indicator continues blinking

by 2Hz for more than 11.5 seconds.
When there is rotation difference of wheels or there
is phase difference between front wheels and axles,
it is difficult to connect front wheels to front axles. The
blinking by 2Hz shows that shifting the transfer gear
or connecting the front wheels is in the middle of
operating. In above case, the indicator’s blinking by
2Hz shows that connecting the front wheels is not
completed (because the indicator’s blinking changes
to 4Hz when the shifting transfer gear is impossible.).
And removal of rotation or phase difference make
connecting the front wheels possible.
Solution 2: When vehicle is running, drive
straight ahead while accelerating and
decelerating. When vehicle is at a stop, move the
vehicle forward and backward from 2 to 3 meters.

When switching from 4WD to 2WD

1. In case that the 4WD indicator continues blinking

by 2Hz .
The 4WD indicator continues blinking by 2Hz until
both shifting the transfer gear and disconnecting the
front wheels are completed when switching 4WD to
2WD. When driveline is loaded with torsional torque,
the shifting transfer gear and disconnecting front
wheels are impossible. In this case, removal of
torsional torque on driveline make the shifting
transfer gear and disconnecting front wheels
possible.
Solution 3: When vehicle is running, drive
straight ahead while accelerating and
decelerating. When vehicle is at a stop, move the
vehicle forward and backward from 2 to 3 meters.

2. In case that the 4WD indicator’s blinking changes

from 2Hz to 4Hz.
Check the position of transfer lever. Is it at “4L”
position? In view of the shifting mechanism of
transfer, the gear shifting from 4WD to 2WD at “4L”
condition is impossible.
Solution 4: Push the 4WD switch to 4WD, shift the
transfer lever to “High” position and re–operate
the 4WD switch to 2WD.

Opel Frontera UBS. Manual - part 130