Isuzu Rodeo UE. Manual - part 68

4B–3

DRIVELINE CONTROL SYSTEM

Normal Operation

The motor actuator mounted on transfer rear case is
driven by signal from 4WD switch on instrument panel.
After complete the connecting transfer front output gear
to, or disconnecting it from, front propeller shaft, condition

of the transfer position switch changes.  The vacuum
solenoid valve (VSV) is driven by the signal from transfer
position switch and the vacuum actuator connects front
wheels to, or disconnect them from, front axles.

Time Chart of Shifting Under Normal Condition

F04RW002

4B–4

DRIVELINE CONTROL SYSTEM

Retrial

The motor actuator starts transfer gear shifting after
signal from 4WD switch on instrument panel has been
received.  But the shifting may be impossible in cold
weather or under high speed condition.  When 2 seconds
have passed since transfer gear shifting started and the
transfer position switch dose not turn on (the gear
engagement is not completed), the motor reverses its
rotation for 1.2 seconds and tries again to shift transfer

gear.  This procedure is repeated 3 times in maximum.
While this procedure, 4WD indicator lamp blinks by 2 Hz.
If the transfer position switch does not turn on after
aforementioned procedure has been repeated 3 times,
the gear shifting is stopped and 4WD indicator lamp’s
blinking changes from 2Hz to 4Hz to notify driver that the
gear shifting is stopped.  This blinking of indicator lamp
continues until 4WD switch is returned from 4WD to 2WD.

Time Chart of Shifting Under Severe Condition (retrial)

F04RX004

4B–5

DRIVELINE CONTROL SYSTEM

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

F04RX005

4WD out signal to other Electronic Hydraulic Control
Unit : ECU of shift on the fly 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)

2WD (Open)

240 ms

4WD

4WD (Close)

4WD (Close)

4B–6

DRIVELINE CONTROL SYSTEM

Functions of Indicator Lamp

Indication of vehicle condition : Indicator lamp is
controlled by ECU of shift on the fly and shows vehicle
conditions as below.

Indicator

Vehicle condition

4WD switch

Transfer position

switch

Front axle switch

Off

2WD

Off (Close)

2WD (Open)

2WD (Open)

On

4WD

On (Open)

4WD (Close)

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)

2WD (Open)

Off (Close)

4WD (Close)

4WD (Close)

Bulb check :The bulb of indicator lamp is checked for 2
seconds when ignition key is turned on.

Time Chart of Bulb Checking

F04RW004

Retrials from 2WD to 4WD :In cold weather or under
high speed condition, the gear shifting (engagement)
sometimes dose 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.)