check engine ISUZU AXIOM 2002 Service Owner's Manual

INTELLIGENT SUSPENSION3F±25
DTC6 Stop Lamp Switch Open Circuit or Short
Circuit Description
The brake switch is used to indicate brake pedal status.
The normally opened brake switch signal voltage circuit is
opened.
Brake switch supplies a B+ signal on circuit RED to the
control unit when the brakes are applied. The control unit
uses this signal to work dive control when the brakes are
applied.
Diagnostic Aids

Inspect the wiring for poor electrical connections at
the control unit and brake switch. Look for possible
bent, backed out, deformed or damaged terminals.
Check for weak terminal tension as well. Also check
for a chafed wire that could short to bare metal or
other wiring. Inspect for a broken wire inside the
insulation.

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.

Check customer driving habits and/or unusual driving
conditions (i.e. stop and go, highway).

Check brake switch for proper mounting and
adjustment.
DTC6 Stop Lamp Switch Open Circuit or Short
StepActionValue(s)Ye sNo
11. With the engine ªoffº, turn the ignition switch ªonº. If
ABS code is set, check applicable fuse.
2. Apply then release the brake pedal.
Does the brake lamp come on when the brake pedal is
applied and does it come off when the brake pedal is
released?
Ð
Go to
Diagnostic
Aids
Go to Step 2
21. Connect the test light to ground.
2. Back probe ignition feed circuit terminal I±31
terminal 1 at the brake switch.
Is the test light ªonº?
ÐGo to Step 3Go to Step 4
31. Connect the test light to ground.
2. Back probe circuit terminal I±31 terminal 4 at the
brake switch.
Is the test light ªoffº?
ÐGo to Step 7Go to Step 5
4Repair the open in battery feed circuit terminal I±31
terminal 1 to the brake switch.
If fuse is open, check circuit terminal I±31 terminal 4 for
a short to ground.
Is the replacement complete?
ÐGo to Step 13Ð
5Disconnect brake switch connector I±31 and ignition
switch ªonº.
Is the test light ªonº?
ÐGo to Step 8Go to Step 6
6Check the brake switch short (I±31 terminal 1 and I±31
terminal 4).
Was a problem found?
ÐGo to Step 9Go to Step 10
7Check circuit terminal I±31 terminal 4 for a short to
voltage.
Ignition switch ªonº.
Is the test light ªonº?
ÐGo to Step 8Go to Step 10
81. Disconnect the control unit connector C±44.
2. Check circuit terminal I±31 terminal 4 for a short to
voltage.
Was a problem found?
ÐGo to Step 13Go to Step 10

INTELLIGENT SUSPENSION3F±27
DTC7 Engine Speed Signal Open Circuit or Short
Circuit Description
PCM (Powertrain Control Module) converts signals from
the crankshaft position sensor into the engine speed
signals (pulse) and sends these to the control unit and
tachometer.
Diagnostic Aids

Inspect the wiring for poor electrical connections at
the control unit connector. Look for possible bent,
backed out, deformed, or damaged terminals. Check
for weak terminal tension as well.
Also check for a chafed wire that could short to bare
metal or other wiring. Inspect for a broken wire inside
the insulation.

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.

Check harness routing for a potential short to ground
in circuit BLK/RED.
DTC7 Engine Speed Signal Open Circuit or Short
StepActionValue(s)Ye sNo
1NOTE: Confirm that DTC P0336 or P0337 does not
exist.
If either exists, warning lamps, ªCHECK ENGINEº and
ªCHECK TRANSº are turned on. Repair the engine,
referring to section 6E
Driveability and Emission.
1. Turn on the starter switch.
2. Start the engine.
3. Open the throttle and rev up engine speed.
Does the tachometer operate according to engine
speed?
ÐGo to Step 3Go to Step 2
2Repair the tachometer, referring to section 8D Wiring
System in Body and Accessories
.
ÐGo to Step 6Ð
31. Turn off the starter switch.
2. Check continuity between the control unit connector
C±44 terminal 59 and PCM connector E±34
terminal F7.
Is there continuity ?
ÐGo to Step 4Go to Step 5
4Replace the control unit.
ÐGo to Step 6Ð
5Repair the circuit.
ÐGo to Step 6Ð
61. Reconnect all components, ensure all components
are properly mounted.
2. Clear the DTC.
3. Conduct a test drive.
Has the last test failed or does the current DTC exist?
Ð
Begin diagnosis
again
Go to
Step 1
Repair
verified

DIFFERENTIAL (REAR)4A2±3
Diagnosis
Many noises that seem to come from the rear axle
actually originate from other sources such as tires, road
surface, wheel bearings, engine, transmission, muffler, or
body drumming. Investigate to find the source of the
noise before disassembling the rear axle. Rear axles, like
any other mechanical device, are not absolutely quiet but
should be considered quiet unless some abnormal noise
is present.
To make a systematic check for axle noise, observe the
following:
1. Select a level asphalt road to reduce tire noise and
body drumming.
2. Check rear axle lubricant level to assure correct level,
and then drive the vehicle far enough to thoroughly
warm up the rear axle lubricant.
3. Note the speed at which noise occurs. Stop the
vehicle and put the transmission in neutral. Run the
engine speed slowly up and down to determine if the
noise is caused by exhaust, muffler noise, or other
engine conditions.
4. Tire noise changes with different road surfaces; axle
noises do not. Temporarily inflate all tires to 344 kPa
(50 psi) (for test purposes only). This will change
noise caused by tires but will not affect noise caused
by the rear axle.
Rear axle nose usually stops when coasting at
speeds under 48 km/h (30 mph); however, tire noise
continues with a lower tone. Rear axle noise usually
changes when comparing pull and coast, but tire
noise stays about the same.
Distinguish between tire noise and rear axle noise by
noting if the noise changes with various speeds or
sudden acceleration and deceleration. Exhaust and
axle noise vary under these conditions, while tire
noise remains constant and is more pronounced at
speeds of 32 to 48 km/h (20 to 30 mph). Further check
for tire noise by driving the vehicle over smooth
pavements or dirt roads (not gravel) with the tires at
normal pressure. If the noise is caused by tires, it will
change noticeably with changes in road surface.
5. Loose or rough front wheel bearings will cause noise
which may be confused with rear axle noise; however,
front wheel bearing noise does not change when
comparing drive and coast. Light application of the
brake while holding vehicle speed steady will often
cause wheel bearing noise to diminish. Front wheel
bearings may be checked for noise by jacking up the
wheels and spinning them or by shaking the wheels to
determine if bearings are loose.
6. Rear suspension rubber bushings and spring
insulators dampen out rear axle noise when correctly
installed. Check to see that there is no link or rod
loosened or metal±to±metal contact.7. Make sure that there is no metal±to±metal contact
between the floor and the frame.
After the noise has been determined to be in the axle, the
type of axle noise should be determined, in order to make
any necessary repairs.
Gear Noise
Gear noise (whine) is audible from 32 to 89 km/h (20 to 55
mph) under four driving conditions.
1. In drive under acceleration or heavy pull.
2. Driving under load or under constant speed.
3. When using enough throttle to keep the vehicle from
driving the engine while the vehicle slows down
gradually (engine still pulls slightly).
4. When coasting with the vehicle in gear and the throttle
closed. The gear noise is usually more noticeable
between 48 and 64 km/h (30 and 40 mph) and 80 and
89 km/h (50 and 55 mph).
Bearing Noise
Bad bearings generally produce a rough growl or grating
sound, rather than the whine typical of gear noise.
Bearing noise frequently ªwow±wowsº at bearing rpm,
indicating a bad pinion or rear axle side bearing. This
noise can be confused with rear wheel bearing noise.
Rear Wheel Bearing Noise
Rear wheel bearing noise continues to be heard while
coasting at low speed with transmission in the neutral.
Noise may diminish by gentle braking. Jack up the rear
wheels, spin them by hand and listen for noise at the
hubs. Replace any faulty wheel bearings.
Knock At Low Speeds
Low speed knock can be caused by worn universal joints
or a side gear hub counter bore in the cage that is worn
oversize. Inspect and replace universal joints or cage and
side gears as required.
Backlash Clunk
Excessive clunk on acceleration and deceleration can be
caused by a worn rear axle pinion shaft, a worn cage,
excessive clearance between the axle and the side gear
splines, excessive clearance between the side gear hub
and the counterbore in the cage, worn pinion and side
gear teeth, worn thrust washers, or excessive drive pinion
and ring gear backlash. Remove worn parts and replace
as required. Select close±fitting parts when possible.
Adjust pinion and ring gear backlash.

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.

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