ECU ISUZU AXIOM 2002 Service Owner's Manual

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±36
Diagnosis from Trouble Codes

Diagnose the fault that have been saved to the control
unit according to the system self-diagnostic function.
Check flow
Trouble codePhenomenonStandard
1 23, 36, 37, 38The ECU has failed.Ð
P1712, P1714
StepActionYe sNo
1Turn on the starter switch.
Is the trouble reproduced?Replace the ECU
and conduct the
test run.
Go to
Step 3Go to Step 2
21. Clear the trouble codes.
2. Conduct the test run.
Is the trouble reproduced during the test run?
Replace the ECU
and conduct the
test run.
Go to
Step 3
The trouble is not
reproduced.
Refer to
ªTrouble
intermittently
observedº.
Go to Step 3
31. Check that all the parts are mounted.
2. Clear the trouble codes.
Is this step complete?
Verify the repair.Return to Step 3

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±42
StepActionYe sNo
11. Connect TECH 2.
While running in TOD mode, does TECH±2's front speed sensor
indication change with vehicle speed?
Go to Step 2
Repair and
inspection front
speed sensor
tone wheel.
Go to
Step 6
21. Clear the trouble code.
While running at 40 km/h or 25 mph in TOD mode for 30
consecutive sec, is the trouble code reissued?
Go to Step 3
The trouble is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
31. 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 10
and 25?
Repair the circuit.
Go to
Step 6Go to Step 4
41. 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 5
Repair the circuit.
Go to
Step 5
51. Clear the trouble code.
While running at 40 km/h or 25 mph in TOD mode for 30
consecutive sec, is the trouble code reissued?
Replace ECU.
Go to
Step 6Go to Step 6
61. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Return to Step 6

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±44
StepActionYe sNo
11. Connect TECH 2.
While running in TOD mode, does TECH±2's rear speed sensor
indication change with vehicle speed?
Go to Step 2
Repair and
inspection front
speed sensor
tone wheel.
Go to
Step 6
21. Clear the trouble code.
While running at 40 km/h or 25 mph in TOD mode for 30
consecutive sec, is the trouble code reissued?
Go to Step 3
The trouble is not
reproduced.
Refer to
ªTroubles
intermittently
observedº
.
31. 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 5Go to Step 4
41. 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 5
Repair the circuit.
Go to
Step 5
51. Clear the trouble code.
While running at 40 km/h or 25 mph in TOD mode for 30
consecutive sec, is the trouble code reissued?
Replace ECU.
Go to
Step 6Go to Step 6
61. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Return to Step 6

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

4B2±49
DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
11. Turn off the starter switch.
Is the battery voltage normal?
Go to Step 2
Charge or
replace the
battery.
Go to
Step 7
21. Turn on the starter switch.
Does the voltage between terminals 15 and 47 fall within the
standard range?
Go to Step 3Go to Step 4
31. Clear the trouble code.
2. Turn on the starter switch.
Is there DTC21 (P1716)?
Go to Step 4
Refer to ªTrouble
intermittently
observedº.
41. Turn off the starter switch.
2. Disconnect the ECU connector.
3. Turn on the starter switch.
Does the voltage between terminals (C±38)15 and (C±37)25 fall
within the standard range above?
The ECU has
failed. Replace
the ECU.
Go to
Step 7Go to Step 5
5Is the harness healthy?
Go to Step 6
Repair the
harness.
Go to
Step 7
6Is the TPS healthy?
Go to Step 7
Replace the TPS.
Go to
Step 7
71. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Go to Step 7

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

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±56
StepActionYe sNo
11. Turn on the starter switch.
2. Set the transfer to the 2H mode.
Is the battery voltage observed between terminals 23 and 47?
Go to Step 2Go to Step 5
2Is 5V observed between terminals 42 and 47?Go to Step 3Go to Step 6
31. Set the transfer to the TOD mode.
Does the voltage between terminals 23 and 47 indicate 0~1V?
Go to Step 4
The ECU has
failed. Replace
the ECU.
Go to
Step 7
4Does the voltage between terminals 42 and 47 indicate 0V?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
The shift on the
fly system is
failed (refer to
Section 4B1 and
4C
).
Go to
Step 7
5Does the TOD indicator show the 2H mode?The ECU has
failed. Replace
the ECU.
Go to
Step 7
See ªTrouble
Diagnosis
Depending on
The Status of
TOD Indicatorº.
6Set the transfer to the TOD mode.
Does the voltage between terminals 23 and 47 indicate 0~1V?The shift on the
fly system has
failed (refer to
Section 4B1 and
4C
).
Go to
Step 7
The ECU has
failed. Replace
the ECU.
Go to
Step 7
71. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Verify the repair.Return to Step 7

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±58
StepActionYe sNo
11. Turn off the starter switch.
2. Disconnect the ECU connector from ECU.
3. Disconnect ADC control unit connector (C±41).
Is the continuity established between terminals (C±37) 1 and
(C±41) 4? After checking, connect the ADC control unit
connector.
Go to Step 2
The harness is
broken. Repair
the circuit.
Go to
Step 6
21. Disconnect the battery ground cable.
Is there the continuity between the connector terminal (C±37) 1
and (C±38) 14?The harness is
short-circuited to
VIGN. Repair the
circuit.
Go to
Step 6Go to Step 3
31. Disconnect the battery ground cable.
Is there the continuity between the connector terminal (C±37) 1
and (C±37) 12?The harness is
short-circuited to
VB. Repair the
circuit.
Go to
Step 6Go to Step 4
4Is the resistance between the connector terminal (C±37) 1 and
(C±37) 25 less than 1
?The harness is
short-circuited to
GND. Repair the
circuit.
Go to
Step 6Go to Step 5
51. Turn off the starter switch.
2. Connect ECU connector.
3. Turn on the starter switch.
4. Set the transfer to the 2H mode.
Is the battery voltage observed between the connector (C±37)
terminals 1 and 25?The phenomenon
is not
reproduced.
Refer to
ªTrouble
intermittently
observedº,
or refer to ªSec
4B1 Shift on the
Flyº.
The ECU has
failed. Replace
the ECU.
Go to
Step 6
61. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Verify the repair.Return to Step 6