Opel Frontera UBS. Manual - part 1960

4B1–25

DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)

Diagnosis of the Faults Based on the
Status of 4WD Indicator Lamp, 4WD
Switch and T/F Change Lever

Diagnosis charts are shown on below.  If troubles can not
be solved after every chart was traced, troubles may
occur in the 4WD control unit.  In this case, replace the
4WD control unit and trace every chart again.

Fault on switching from 2WD to 4WD

1. In case that 4WD indicator’s blinking changes

from 2Hz to 4Hz after Solution 1 is carried out.
Faults occur in the motor actuator or the transfer case
assembly. Remove the motor actuator and check
function. If problem was found and it was repaired, try
Solution 1 again.  After that, disassemble the
transfer case assembly for check and repair or
replace. If incident is not improved after above
mentioned actions were  taken, replace the 4WD
control unit.

2. In case that 4WD indicator does not blink nor

light, when switching from 2WD to 4WD.

Step

Action

Yes

No

1

Is ignition turned on?

Go to Step 2

Turn on the

ignition and trace

this chart from

start.

2

Does the indicator light comes on when the engine is not started?

Go to Step 3

Burning out of

indicator lamp or

disconnection of

harness wire.

Trace this chart

from the start

after repair or

replace.

3

Start the engine.

Is the 4WD switch turned from 2WD to 4WD?

Short-circuit

(body short) on

harness of the

4WD switch.

Fault of the 4WD

switch (holding

the closed

condition).

Trace this chart

from the start

after repair or

replace.

Push the 4WD

switch to 4WD.

4B1–26DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)

3. Case that the indicator keeps blinking by 2Hz

after aforementioned Solution 2 is carried out.

Step

Action

Yes

No

1

Check the air pressure and wear of all tires.

Were problems found?

Try Solution 2

after adjust the

air pressure and

replace worn

tires.

Go to Step 2

2

Can the transfer lever be operated from High to 4L or vice versa?

Go to Step 3

Disconnection of

the motor

actuator harness

wiring.  Trace this

chart from the

start after repair

or replace.

Faults on the

motor actuator.

Trace this chart

from the start

after replace.

Internal faults of

transfer case.

Disassemble the

transfer case for

check.  Trace this

chart from the

start after repair

or replace.

3

Pull out the hoses from vacuum actuator and operate 4WD
switch.

Is there negative pressure on either of hoses?

Go to Step 4

Faults on the

transfer position

switch or its

harness.  Trace

this chart from

the start after

repair or replace.

Faults on the

VSV main body,

its harness or

vacuuming

system.  Trace

the front axle

diagnosis chart in

this section.

After that, trace

this chart from

the start.

4

Check the axle switch.

Were problems found?

Internal faults on

axle switch.

Trace this chart

from the start

after replace.

Disconnection on

the axle harness.

Trace this chart

from the start

after repair or

replace.

Faults on Front

Axle ASM.  Trace

the front axle

diagnosis chart in

this section.

After that, trace

this chart from

the start.

4B1–27

DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)

Fault on switching from 4WD to 2WD

1. Case that indicator does not blink nor turn out.

Step

Action

Yes

No

1

Does the indicator turn out by ignition off?

Go to Step 2

Short circuit of

the indicator

harness.

2

Is the 4WD switch on 2WD position?

Disconnection on

the 4WD switch

harness or

breakdown of the

4WD switch in

open state.

Trace this chart

from the start

after repair or

replace.

Turn the 4WD

switch to 2WD

position.  Trace

this chart from

the start.

4B1–28DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)

2. Case that indicator keeps 2Hz blinking after

aforementioned Solution 3 is carried out.

Step

Action

Yes

No

1

Check the air pressure and wear of all tires.

Were problems found?

Try Solution 3

after adjust the

air pressure and

replace worn

tires.

Go to Step 2

2

Can the transfer lever be operated from High to 4L or vice versa?

Faults on the

harness wiring of

motor actuator.

Trace this chart

from the start

after repair or

replace.

Internal faults on

transfer case.

Disassemble the

transfer case for

check.  Trace this

chart from the

start after repair

or replace.

Faults on the

motor actuator.

Trace this chart

from the start

after or replace.

Go to Step 3

3

Pull out the hoses from vacuum actuator and operate 4WD
switch.

Is there negative pressure on either of hoses?

Go to Step 4

Faults on the

transfer position

switch or its

harness.  Trace

this chart from

the start after

repair or replace.

Faults on the

VSV main body,

its harness or

vacuuming

system.  Trace

the front axle

diagnosis chart in

this section.

After that, trace

this chart from

the start.

4

Check the axle switch.

Were problems found?

Internal faults on

axle switch.

Trace this chart

from the start

after replace.

Faults on Front

Axle ASM.  Trace

the front axle

diagnosis chart in

this section.

After that, trace

this chart from

the start.

Short circuit

(body short) or

disconnection of

the axle harness.

Trace this chart

from the start

after repair or

replace.