Opel Frontera UBS. Manual

4B2–13

DRIVE LINE CONTROL SYSTEM (TOD)

Diagnosis

General Information Diagnosis

The troubles on TOD are classified into the group that can
be identified by the lighting status of the TOD indicator
lamps and those that can be recognized as abnormal
phenomena of the vehicle by the driver.
The troubles that can be identified by the lighting status of
the TOD indicator lamps are examined by the procedures
“Diagnosis from Trouble Codes” and “Trouble Diagnosis
Depending on The Status of TOD indicator”. The troubles
that can be recognized as abnormal phenomena of the
vehicle by the driver are examined by the procedure
“Diagnosis from symptom”.

Self-diagnosis

The control unit has a function of self-diagnosis. If a
trouble occurs in the course of system startup, the control
unit blinks the CHECK lamp and saves the trouble code.

C07RW021

NOTE: If an intermittent fault occurs, the control unit
stops blinking upon removal of the fault. The trouble code
is saved to the control unit.

4B2–15

DRIVE LINE CONTROL SYSTEM (TOD)

How to Clear The Trouble Code
The trouble codes saved to the control unit can be deleted
by the following procedure if the starter switch is being in
the OFF position.

1. Shift the transfer lever to the neutral position between

HIGH and 4L, and short-circuit the self-diagnostic
connector.

NOTE: The neutral position between HIGH and 4L refers
to the point that turns off the TOD indicator lamps.
(However, be sure to check the position before
short-circuiting the self-diagnostic connector.)

C07RW011

2. Turn on the starter switch while maintaining the state

of step 1, and step on the brake pedal five times within
five seconds from the first step on. (Note that “five
times” includes the first step on). (The TOD indicator
lamps display the 4L mode whenever the brake pedal
is stepped on.)

3. If the conditions shown in steps 1 and 2 are met, the

trouble codes saved to the control unit are cleared.
(After the codes are completely deleted, the code 12
that indicates the normal condition is continuously
displayed.)

Precautions on Diagnosis

Replacement of Control Unit
The control unit itself rarely fails. In most cases, the
harnesses have failed (i.e. short-circuit) to cause
secondary troubles. Other cases include that the cause
has been unknown due to intermittent occurrence of
troubles and the troubles are removed accidentally along
with replacement of control unit, resulting in misjudgment
of cause. Therefore, before replacing the control unit,
check the connector joints and whether the unspecified
current flows in the control unit due to short-circuit
between harnesses.

Trouble Intermittently Observed
Troubles intermittently observed are mostly attributable
to temporary imperfect connection of harnesses and
connectors.
When such troubles are found, check the associated
circuit according to the following procedure.

1. Check whether improper connectors are plugged in

or connector terminals are completely engaged.

2. Check whether the terminals are deformed or

damaged. If yes, remove the deformation or damage
and connect the terminals securely.

3. It is likely that wires in the harness are falsely broken.

Therefore, in examination of failed harness circuit,
shake the harness for check to such extent that the
harness will not be damaged.

Test Run of Failed TOD Vehicle
If the TOD indicator lamps experienced faulty operation
even once in the past, the failed portion can be identified
by use of the procedure “Diagnosis from Trouble Codes”
or “Trouble Diagnosis Depending on The Status of TOD
Indicator”. If the troubles that are only recognized as
abnormal phenomena of the vehicle by the driver are
observed, conduct the test run in the following procedure
to reproduce the faulty phenomena and diagnose the fault
for each phenomenon.

1. Start the engine, and check that the TOD indicator

lamps are turned on for about two seconds for initial
check; the CHECK lamp goes off; and the TOD
indicator lamps display the specified drive mode. (If
the CHECK lamp starts blinking, read the trouble
codes and identify the failed portion.)

2. While keeping the vehicle standstill, operate the 4WD

switch and shift the transfer lever to change the
modes: 2H mode

→

TOD mode

→

4L mode

→

TOD

mode

→

2H mode. Check that the TOD indicator

lamps correctly display the status whenever the
mode is changed. If the transition status is displayed
during the shift operation, run the vehicle a little to
complete shifting.

3. Slowly start the vehicle in the TOD mode, and add the

power to accelerate to at least 40 km/h and maintain
the speed for about two minutes. Apply the brake to
completely stop the vehicle. Repeat this test pattern
at least three times.

4. Turn the steering to the right end (or left end) in the

TOD mode, and slowly start the vehicle and make a
circle five times. Next, conduct the same test in the 2H
mode.

5. Slowly start the vehicle in the TOD mode, and

accelerate to at least 40 km/h. Keep the established
speed, carefully change the mode in the sequence
“TOD mode

→

2H mode

→

TOD mode” while checking

that the shift is complete in each mode change. After
the test, apply the brake to completely stop the
vehicle.

6. Slowly start the vehicle in the TOD mode, and

accelerate to at least 40 km/h. Apply the brake
strongly so that the ABS works, and completely stop
the vehicle.

Opel Frontera UBS. Manual - part 1018