2002 ISUZU AXIOM check engine

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.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±26
Checking Failed Pin
Connector Pin Assignment

TOD control unit pin assignment
D04RY00011
No.NAMECONTENTS
1N.C Not used
2ENG REVEngine Speed
3N.CNot used
4N.CNot used
5N.C Not used
6N.CNot used
7IND.ADisplay Front
8IND. CDisplay Rear
9N.C Not used
10N.C Not used
11EMCClutch Solenoid
12REFSpeed Reference
13COM (±)Speed GND
14VIGIgnition
15TPSTPS (PWM)
16TECH 2TECH±2
17N. CNot used
18N. CNot used
19IND. BDisplay Auto
20CHK TODCheck TOD
21N.CNot used
22PWR GNDPower Ground
23ADC (+)Axle Disconnect Output
24COM GNDShift Motor Position GND
25MTR POS3Shift Motot Position 3

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±30
Checking Failed TOD Control Unit Pin
NOTE:
1. Unplug the ECU connector and the pins, unless
otherwise specified.
2. Before removing the ECU, turn off the ignition switch.
3. If the standard values are not observed, check the
pins with other testers.
Check
Pin
No.Circuit to be
testedIgnition
Switch
PositionEngine
StateUnit
Scale/
RangeMeasure
between
Pin No.Standard ValueNote
22P-GNDOFFSTOP
22, 47Continuity : OK
46GNDIOFFSTOP
46, 47Continuity : OK
47GND 2OFFSTOP
47, GNDContinuity : OK
314H SWOFFSTOP
31, 47No continuity
(high, 4L) : OK
444L SWOFFSTOP
44, 47No continuity
(high) and
continuity (4L) :
OK
42AXLE SWONRUN
42, 47Continuity(TOD,
4L) : OKRemove ECU connector and start
the engine. Move the vehicle forth
and back to connect axle surely.
29DIAGOFFSTOP
29 (TOD),
8 (DLC
Connec-
tor)Continuity : OKDLC connector terminal 8
7IND.AONSTOPDCV7 (+), 47
(±)8.0 ~14.5 Vwhen the indicator lamp is turned
off.
20CHECK
TODONSTOPDCV20 (+), 47
(±)8.0 ~14.5 VWhen the indicator lamp is turned
off.
33ABS INONSTOPDCV33 (+), 47
(±)6.0 ~11.0 V
12REFONSTOPDCV12 (+), 47
(±)5 ~9 VConnect ECU
32FRT.(+)ONSTOPDCV32 (+), 47
(±)0.7 ~6 VConnect ECU and move the
vehicle (off one tooth of speed
sensor ring) making sure of
voltage change.
45RR.(+)ONSTOPDCV45 (+), 47
(±)0.7 ~6 VConnect ECU and move the
vehicle (off one tooth of speed
sensor ring) making sure of
voltage change.
13COM(-)ONSTOPDCV13 (+), 47
(±)0VConnect ECU
14VIGONSTOPDCV14 (+), 47
(±)8 ~14.5 V
34VBOFFSTOPDCV34 (+), 47
(±)8.0 ~14.5 V
37BRAKE
SWOFFSTOPDCV37 (+), 47
(±)8 ~14.5 VPress brake pedal
15TPSONSTOPDCV15 (+), 47
(±)PWM duty cycle
10%(MAX) ± 90
%(MIN)Step on the accelerator pedal and
make sure that duty cycle
changes.

4B2±31
DRIVE LINE CONTROL SYSTEM (TOD)
Check
Pin
No.Note Standard Value Measure
between
Pin No. Unit
Scale/
Range Engine
State Ignition
Switch
Position Circuit to be
tested
364WD
OUTOFFSTOP
36, 477 ~12 k
Disconnect battery GND terminal
11EMC(+)OFFSTOP
11, 221.0 ~5.0
Disconnect battery GND terminal
30TOD SW
AONSTOPDCV30 (+), 47
(±)SW: TOD, 4L: 0
V
SW:2H:8.0 ~
14.5 V
43TOD
SWBONSTOPDCV43 (+), 47
(±)SW: 2H,
TOD:0V
SW: 4L: 8.0 ~
14.5V
40LIGHTONSTOPDCV40 (+), 47
(±)SW OFF : 0 V
SW ON : 8.0 ~
14.5 V
19IND BONSTOPDCV19 (+), 47
(±)8.0 ~14.5 VWhen the indicator lamp is turned
off
8IND CONSTOPDCV8 (+), 47
(±)8.0 ~ 14.5 VWhen the indicator lamp is turned
off
27AT POSCONSTOPDCV27 (+), 47
(±)ON:D, 3, 2, 1
OFF:PRNON:8.0 ~ 14.5 V
OFF:0V
41AT POSBONSTOPDCV41 (+), 47
(±)ON:R, N, D, 3
OFF:P, 2, 1ON:8.0 ~ 14.5 V
OFF:0V
28AT POSAONSTOPDCV28 (+), 47
(±)ON:P, R, 3, 2
OFF:N, D, 1ON:8.0 ~ 14.5 V
OFF:0V
2ENG REVONRUNms2, 47Waveform
(PWM)50 ms (1000 rpm)

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±38
StepActionYe sNo
11. Start the engine.
2. Select TOD mode.
Is there the memory except DTC 14(P1731)?
Go to Step 4Go to Step 2
21. Turn off the starter switch.
2. Disconnect the ECU connector (C±38) and (C±37).
Is there the continuity between (C±37) terminal 10 and 25?
Repair the circuit.
Go to
Step 7Go to Step 3
31. Disconnect the transfer connector (A±1).
Is there the continuity between the connector (C±37) terminal 10
and the connector (A±1) terminal 6, the connector (C±38) terminal
12 and connector (A±1) terminal 2, and the connector (C±38)
terminal 13 and connector (A±1) terminal 10?
Replace the front
speed sensor.
Go to
Step 7
Repair the circuit.
Go to
Step 7
4Is the memory DTC 24(P1733)?
Go to Step 5
Refer to other
trouble check
flow.
5Is there the continuity between harnesses of terminal 32 and 45
(vehicle side terminal of the front and rear speed sensor)?
Go to Step 6
Repair the circuit.
Go to
Step 7
6Is there the continuity between harnesses of terminal 12 and 13
(vehicle side terminal of the speed sensor COM(±) and ref)?Replace front and
rear speed
sensor.
Go to
Step 7
Repair the circuit.
Go to
Step 7
71. Check that all the parts are mounted.
2. Clear the trouble code.
Is the step complete?
Verify the repair.Return to Step 7

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±40
StepActionYe sNo
11. Start the engine.
2. Select TOD mode.
Is there the memory except DTC 24(P1733)?
Go to Step 4Go to Step 2
21. Turn off the starter switch.
2. Disconnect the ECU connector (C±38) and (C±37).
Is there the continuity between the connector (C±37) terminal 23
and 25?
Repair the circuit.
Go to
Step 7Go to Step 3
31. Disconnect the transfer connector (A±1).
Is there the continuity between the connector (C±37) terminal 23
and the connector (A±1) terminal 5, the connector (C±38) terminal
12 and connector (A±1) terminal 1, and the connector (C±38)
terminal 13 and connector (A±1) terminal 9?
Replace the rear
speed sensor.
Go to
Step 7
Repair the circuit.
Go to
Step 7
4Is the memory DTC 14(P1731)?
Go to Step 5
Refer to other
trouble cheek
flow.
5Is there the continuity between harnesses of terminal 32 and 45
(vehicle side terminal of the front and rear speed sensor)?
Go to Step 6
Repair the circuit
Go to
Step 7
6Is there the continuity between harnesses of terminal 12 and 13
(vehicle side terminal of the speed sensor COM(±) and ref)?Replace front and
rear speed
sensor.
Go to
Step 7
Repair the circuit.
Go to
Step 7
71. Check that all the parts are mounted.
2. Clear the trouble code.
Is the step complete?
Verify the repairReturn to Step 7

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±46
StepActionYe sNo
11. Start the engine.
Does the voltage between terminals 12 and 47 meet the standard
5V?Refer to ªTrouble
intermittently
observedº.
Go to Step 2
2Is the voltage below the standard?Go to Step 3Go to Step 7
31. Turn off the starter switch.
2. Disconnect the ECU connector.
Is the continuity established between vehicle harness terminals
(C±38)12 and (C±37)25?
Go to Step 4
The ECU is
failed. Replace
the ECU.
Go to
Step 8
41. Disconnect the H-7 connector.
Is the continuity established between floor harness connector
terminals (H-7)2 and (H-7)15?
Go to Step 5
Short to GND
between
(C±38)12 and
(H±7)2.
Repair the circuit.
Go to
Step 8
51. Disconnect the A-1 connector.
Is the continuity established between transfer harness connector
male terminals (A±1)1 and (A±1)7?
Replace the rear
speed sensor.
Go to
Step 8
The reference
harness for the
rear speed
sensor is
short±circuited to
GND. Repair the
circuit.
Go to
Step 6
61. Disconnect the A-1 connector.
Is the continuity established between transfer harness connector
terminals (A±1)2 and (A±1)7?
Replace the front
speed sensor.
Go to
Step 8
The reference
harness for the
rear speed
sensor is
short±circuited to
GND. Repair the
circuit.
Go to
Step 8
71. Turn off the starter switch.
2. Disconnect the ECU connector.
3. Turn on the starter switch.
Is the battery voltage observed between harness connector
terminals (C±38)12 and (C±37)25?
Repair the circuit.
Go to
Step 8
The ECU has
failed. Replace
the ECU.
Go to
Step 8
81. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº
Go to Step 8

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±54
StepActionYe sNo
11. Clear the trouble code.
2. Start the engine
3. Set the TOD mode.
Is there DTC31 (P1721)?
Go to Step 2
Refer to ªTrouble
intermittently
observedº.
21. Turn off the starter switch.
2. Disconnect the ECU connector from ECU.
Is the continuity established between terminals (C±38)11 and
(C±38)22?
Go to Step 3Go to Step 5
31. Connect the ECU connector.
2. Start the engine.
3. Set the TOD mode.
Does the voltage between terminals 11 and 22 indicate at least
0.4V?
Go to Step 4Go to Step 6
4Is the battery voltage always observed between terminals 11 and
22?The harness is
short±circuited on
the battery.
Repair the circuit.
Go to
Step 8Go to Step 6
51. Disconnect the A±1 connector.
Is the continuity established between transfer connector
terminals (A±1)8 and (A±1)7?
The harness is
broken. Repair
the circuit.
Go to
Step 8
Replace the
transfer
electromagnetic
coil (solenoid
clutch).
Go to
Step 8
61. Turn off the starter switch.
2. Disconnect the ECU connector from ECU.
Is the resistance between the connector (C±38) terminal 11 and
22 1.0 ~ 5.0
?The ECU has
failed. Replace
the ECU
Go to
Step 8Go to Step 7
7Is the resistance between the transfer connector (A±1) terminal 8
and 7 1.0 ~ 5.0
?
The harness is
disconnection or
short to GND.
Repair the circuit.
Go to
Step 8
Replace the
transfer
electromagnetic
coil (solenoid
clutch).
Go to
Step 8
81. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Return to Step 8