ECU ISUZU TROOPER 1998 Service Owner's Guide

4B2±37 DRIVE LINE CONTROL SYSTEM (TOD)
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 rear
speed sensor
tone wheel.
Go to Step 4
2Is the continuity harness of terminal 23 (vehicle side terminal of
the rear speed sensor)?Replace speed
sensor.
Go to Step 3
Repair the circuit.
Go to Step 3
31. Clear the trouble code.
While running at 40 kph in TOD mode for 30 consecutive sec, is
trouble code reissued?
Replace EUC.
Go to Step 4
Go to Step 4
41. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
The trouble is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Return to Step 4

4B2±41 DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
11. Start the engine.
Does the voltage between terminals 15 and 19 meet the standard
5V?
Go to Step 8Go 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
(B±67)7 and (B±67)11?
Go to Step 4
The ECU is
failed. Replace
the ECU.
Go to Step 8
41. Disconnect the H-49 connector.
Is the continuity established between floor harness connector
terminals (H-49)3 and (H-49)9?
Go to Step 5Go to Step 6
51. Disconnect the A±3 connector.
Is the continuity established between transfer harness connector
terminals (A±3)2 and (A±3)7?
Replace the front
speed sensor.
Go to Step 8
The reference
harness for the
front speed
sensor is
short±circuited to
GND. Repair the
circuit.
Go to Step 8
61. Disconnect the A±3 connector.
Is the continuity established between transfer harness connector
terminals (A±3)1 and (A±3)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 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 (B±67)7 and (B±67)11?
Repair the
harness 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±43 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 6
21. Turn on the starter switch.
Does the voltage between terminals 21 and 19 fall within the
standard range above?
Go to Step 6Go to Step 3
31. Turn off the starter switch.
2. Disconnect the ECU connector.
3. Turn on the starter switch.
Does the voltage between terminals (B±68)9 and (B±67)11 fall
within the standard range above?
The ECU has
failed. Replace
the ECU.
Go to Step 6
Go to Step 4
4Is the harness healthy?
Go to Step 5
Repair the
harness.
Go to Step 6
5Is the TPS healthy?
Go to Step 6
Replace the TPS.
Go to Step 6
61. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Go to Step 6

4B2±45 DRIVE LINE CONTROL SYSTEM (TOD)
6VE1
Step
ActionYe sNo
11. Turn off the starter switch.
Is the continuity established between terminals 14 and 19?
Go to Step 2
The harness is
broken. Repair
the circuit.
Go to Step 3
21. Turn on the starter switch.
Does the voltage between terminals 14 and 19 indicate 0V?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº
Go to Step 3
The ECU has
failed. Replace
the ECU.
Go to Step 3
31. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Return to Step 3

4B2±47 DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
11. Turn off the starter switch.
2. Disconnect the ECU connector from ECU.
Is the continuity established between terminals (B±67)4 and
(B±67)12?
Go to Step 2Go to Step 4
21. Connect the ECU connector.
2. Start the engine.
3. Set the TOD mode.
Does the voltage between terminals 4 and 20 indicate at least
0.4V?
Go to Step 3
The ECU has
failed. Replace
the ECU.
Go to Step 5
3Is the battery voltage always observed between terminals 4 and
20?
The harness is
short±circuited on
the battery.
Repair the circuit.
Go to Step 5
The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 5
41. Disconnect the M±27 connector.
Is the continuity established between transfer connector
terminals (A±3)8 and (A±3)7?
The harness is
broken. Repair
the circuit.
Go to Step 5
Replace the
transfer
electromagnetic
coil (solenoid
clutch).
Go to Step 5
51. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Return to Step 5

4B2±49 DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
11. Turn off the starter switch.
2. Disconnect the ECU connector from ECU.
Does the resistance between terminals (B±67)4 and (B±67)12?
indicate 1.0 to 5.0 ohm?
Go to Step 2Go to Step 3
21. Connect the ECU connector.
2. Start the engine.
3. Set the TOD mode.
When the throttle is operated between full close and full open
positions, does the voltage between terminals 4 and 20 indicate at
least 0.1 to 1.0 V?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 4
The ECU has
failed. Replace
the ECU.
Go to Step 4
3Does the resistance between transfer connector terminals (A±3)8
and (A±3)7 indicate 1.0 to 5.0ohm?
The harness is
broken. Repair
the circuit.
Go to Step 4
Replace the
transfer
electromagnetic
coil.
Go to Step 4
41. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Return to Step 4

4B2±51 DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
11. Turn on the starter switch.
2. Set the transfer to the 2H mode.
Is the battery voltage observed between terminals 5 and 19?
Go to Step 2Go to Step 5
2Is the battery voltage observed between terminals 10 and 19?Go to Step 3Go to Step 6
31. Set the transfer to the high (TOD) mode.
Does the voltage between terminals 5 and 19 indicate 0V?
Go to Step 4
The ECU has
failed. Replace
the ECU.
Go to Step 7
4Does the voltage between terminals 10 and 19 indicate 0V?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 7
The shift on the
fly system is
failed (refer to
Section 4C ªFront
Axleº of Chassis
Repair Manual).
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.
Go to Step 7
6Set the transfer to the high (TOD) mode.
Does the voltage between terminals 5 and 19 indicate 0V?The shift on the
fly system has
failed (refer to
Section 4C ªFront
Axleº of Chassis
Repair Manual).
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?
Repeat the
ªDiagnosis Flowº.
Return to Step 7

4B2±53 DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
11. Turn off the starter switch.
2. Disconnect the ECU connector from ECU.
Is the continuity established between terminals (B±67)5 and
(B±67)11?
Go to Step 2
The harness is
broken. Repair
the circuit.
Go to Step 3
2Does the voltage between terminals 5 and 19 indicate 0V?
Go to Step 3
The battery is
short-circuited.
Repair the circuit.
Go to Step 4
31. 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 terminals 5 and 19?The phenomenon
is not reproduced
Refer to
ªTroubles
intermittently
observedº.
Go to Step 4
The ECU has
failed. Replace
the ECU.
Go to Step 4
41. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Return to Step 4

4B2±55 DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
11. Turn off the starter switch.
2. Disconnect the ECU connector from ECU.
Does the resistance between terminals 5 and 19 meet the
standard, R = 21 + 4 ohms?The phenomenon
is not
reproduced.
Refer to
ªTroubles
intermittently
observedº.
Go to Step 4
Go to Step 2
2Is the resistance between terminals 5 and 19 R<2 ohms?The signal line
circuit of the shift
on the fly system
is short-circuited
to GND. Repair
the circuit.
Go to Step 3
Go to Step 3
3Is the resistance between terminals 5 and 19 R= 9+7ohms?The signal line
circuit of the shift
on the fly system
is layer
short-circuited*.
Replace the valve
(VSV).
Go to Step 3
Go to Step 4
41. Check that all the parts are mounted.
2. Clear the trouble code.
Is this step complete?
Repeat the
ªDiagnosis Flowº.
Return to Step 4
*Layer short-circuit : The coil is damaged by overcurrent.

4B2±57 DRIVE LINE CONTROL SYSTEM (TOD)
StepActionYe sNo
11. Turn on the starter switch.
Is the CHECK lamp always turned on?
Go to Step 2Go to Step 3
21. Turn off the starter switch.
2. Disconnect the ECU connector.
3. Turn on the starter switch.
Is the CHECK lamp always turned on?The CHECK
circuit is
short-circuited to
GND. Repair the
circuit.
Go to Step 7
The ECU has
failed. Replace
the ECU.
Go to Step 7
3Turn on the starter switch.
Is the CHECK lamp always turned off?
Go to Step 4Go to Step 6
4Turn on the starter switch.
Is the battery voltage observed between terminals 30 and 19?
Go to Step 5
The CHECK
circuit wires are
broken or the
CHECK lamp is
failed. Repair the
circuit.
Go to Step 7
5Turn off the starter switch.
Is the battery voltage observed between terminals 30 and 19?The battery is
short±circuited.
Repair the
CHECK lamp
circuit.
Go to Step 7
The ECU has
failed. Replace
the ECU.
Go to Step 7
6Turn on the starter switch.
Does the CHECK lamp go off two seconds after?The phenomenon
is not reproduced
Refer to
ªTroubles
intermittently
observedº.
Go to Step 7
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.
Return to Step 7