ISUZU AXIOM 2002 Service Repair Manual

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±12
Indication During Transition of Shift Rod
When the TOD switch is turned, and the signals from the
AXLE switch do not comply with the signal conditions of
the 4H and 4L switch, the indicator lamp state selected on
the TOD switch and light-off mode are repeatedly output
at an interval of 1.0 second.NOTE: After the TOD switch is turned to the specified
position and the AXLE switch generates compliant
signals, the normal output status is returned.
C07R100010
Bulb Check
When the starter switch is turned on, the TOD indicator
lamps go on as shown below.NOTE: Once the starter switch is turned on, all the TOD
indicator lamps are lit for two seconds even if the TOD
switch is in any position.
C07RW016

4B2±13
DRIVE LINE CONTROL SYSTEM (TOD)
Simplified checking method of ABS IN and BRAKE ON signals:
In the event that any of the signal inputs listed below are
observed while the self-diagnostic code is being
displayed (the self-diagnostic connector is short-circuited
to GND), you can simply check the ABS IN and BRAKE
ON signals as shown in the figures below.
C07R200002
Check Lamp
Check Lamp Bulb Check
When the starter switch is turned on in the normal state,
the control unit turns on the CHECK lamp to check the
bulb.
C07RW019

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±14
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
ªDiagnosis from Trouble Codesº and ªTrouble Diagnosis
Depending on The Status of TOD Indicatorº. The troubles
that can be recognized as abnormal phenomena of the
vehicle by the driver are examined by the procedure
ªDiagnosis from symptomº.
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)
Indication Method of Trouble Code

Turn on the starter switch, while the engine does not
start.

Short-circuit terminal 8 of the self-diagnostic
connector to GND (terminal 4 or 5) to display the
trouble code on the CHECK lamp.
826R200011

If no trouble codes exist, code ª12º is displayed
continuously.

If trouble codes exist, code ª12º is displayed three
times, and the trouble codes, starting from the smaller
code number, are displayed three times respectively.
C07RY00018

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±16
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. Short-circuit terminal 8 of the self-diagnostic
connector to GND (terminal 4 or 5).
2. Turn on the starter switch while maintaining the state
of step1, and stop short-circuiting terminal 8 to GND
within five seconds.
826R200011
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 ªDiagnosis from Trouble Codesº
or ªTrouble Diagnosis Depending on the Status of TOD
Indicatorº. 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 TOD
switch 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 (25 mph)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 (25 mph). Keep the
established speed, carefully change the mode in the
sequence ªTOD mode"2H mode "TOD modeº
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 (25 mph). Apply the
brake strongly so that the ABS works, and completely
stop the vehicle.
7. Slowly start the vehicle in the 4L mode, and
accelerate to at least 20 km/h (13 mph). Apply the
brake to completely stop the vehicle.
If the CHECK lamp starts blinking during the test run, read
the trouble codes and give appropriate maintenance
according to the diagnostic procedure. If the TOD
indicator lamps are lit abnormally during the run, check
the lighting condition and give appropriate maintenance
according to the diagnostic procedure. Even if the
phenomena are not observed, try to reproduce the
abnormal state reported by the customer to the possible
extent.

4B2±17
DRIVE LINE CONTROL SYSTEM (TOD)
Post-Repair Check
As long as the starter is not turned off, the TOD indicator
lamps continue blinking even after the failed portion is
repaired. Therefore, upon completion of repair, be sure to
turn off the starter switch once and then turn on it to
conduct the test run sequence specified in steps 1
through 7 above and check that the TOD indicator lamps
no longer show any faulty status.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±18
Basic Diagnostic Flow Chart
C07R100011

4B2±19
DRIVE LINE CONTROL SYSTEM (TOD)
Parts Location
D04R200019
Legend
(1) C±10
(2) C±6
(3) C±5
(4) H±13 H±14
(5) A±1
(6) A±2
(7) I±31
(8) C±41
(9) I±23
(10) I±24(11) I±25
(12) C±39
(13) H±10
(14) C±37 C±38
(15) C±26
(16) C±29
(17) H±3 H±5
(18) E±35
(19) E±34
(20) E±41
(21) H±7

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±20
Circuit Diagram
D04R200026

4B2±21
DRIVE LINE CONTROL SYSTEM (TOD)
D04R200002