2002 ISUZU AXIOM ignition

5A±12BRAKE CONTROL SYSTEM
circuit. The symptom diagnosis chart may also be useful
in isolating the failure. Most intermittent problems are
caused by faulty electrical connections or wiring. When
an intermittent failure is encountered, check suspected
circuits for damage:

Suspected harness damage.

Poor mating of connector halves or terminals not fully
seated in the connector body (backed out).

Improperly formed or damaged terminals.
Test Driving ABS Complaint Vehicles
In case of an intermittent ABS lamp illumination, see
ªDiagnosis by ABS Warning Light illumination Patternº or
go to 5A±37. In some cases, the vehicle may need to be
test driven by following the test procedure below.
1. Start the engine and make sure that the ªABSº W/L
goes OFF. If the W/L remains ON, it means that the
Diagnostic Trouble Code (DTC) is stored. Therefore,
read the code and locate the fault.
NOTE: The DTC cannot be cleared if the vehicle speed
does not exceed 12 km/h (8 mph) at DTC, even though
the repair operation is completed.
2. Start the vehicle and accelerate to about 30 km/h (19
mph) or more.
3. Slowly brake and stop the vehicle completely.
4. Then restart the vehicle and accelerate to about 40
km/h (25 mph) or more.
5. Brake at a time so as to actuate the ABS and stop the
vehicle.
6. Be cautious of abnormality during the test. If the W/L
is actuated while driving, read the DTC and locate the
fault.
7. If the abnormality is not reproduced by the test, make
best efforts to reproduce the situation reported by the
customer.
8. If the abnormality has been detected, repair in
accordance with the ªSYMPTOM DIAGNOSISº .
NOTE:

Be sure to give a test drive on a wide, even road with a
small traffic.

If an abnormality is detected, be sure to suspend the
test and start trouble diagnosis at once.
ªABSº Warning Light
When ABS trouble occurs to actuate ªABSº warning light,
the trouble code corresponding to the trouble is stored in
the EHCU. Only ordinary brake is available with ABS
being unactuated. Even when ªABSº warning light is
actuated, if the starter switch is set ON after setting it OFF
once, the EHCU checks up on the entire system and, if
there is no abnormality, judges ABS to work currently and
the warning light is lit normally even though the trouble
code is stored.
NOTE: Illumination of the ªABSº warning light indicates
that anti-lock braking is no longer available. Power
assisted braking without anti-lock control is still available.
Normal Operation
ªABSº Warning Light
When the ignition is first moved from ªOFFº to ªRUNº , the
amber ªABSº warning light will turn ªONº . The ªABSº
warning light will turn ªONº during engine starting and will
usually stay ªONº for approximately three seconds after
the ignition switch is returned to the ªONº position. The
warning light should remain ªOFFº at all other times.

5A±14BRAKE CONTROL SYSTEM
Getting Started

Before operating the Isuzu PCMCIA card with the
Tech 2, the following steps must be performed:
1. The Isuzu 98 System PCMCIA card (1) inserts into
the Tech 2 (4).
2. Connect the SAE 16/19 adapter (2) to the DLC cable
(3).
3. Connect the DLC cable to the Tech 2 (4).
4. Make sure the vehicle ignition is off.
5. Connect the Tech 2 SAE 16/19 adapter to the vehicle
DLC.
826R200011
6. The vehicle ignition turns on.
7. Power up the Tech 2.
8. Verify the Tech 2 power up display.
060RW009
Operating Procedure
The power up screen is displayed when you power up the
tester with the Isuzu systems PCMCIA card. Follow the
operating procedure below.
060R100102

5A±22BRAKE CONTROL SYSTEM
F05R200006
Basic Diagnostic Flow Chart
StepActionYe sNo
11. Verify complaint with the customer.
2. Questioning to customer.
3. Basic inspection (Refer to
Basic inspection procedure)
Using TECH 2?
Go to Step 2Go to Step 4
2Verify DTC through: ªF0: Diagnostic Trouble Codes.º
Is the DTC stored in the EHCU?Clear code and
check for
repeatability.
Go to
Step 3Go to Step 5
31. Repair of faulty part.
2. Clear DTC.
3. Inspection of ªABSº W/L Illumination pattern with ignition SW
ªONº.
4. Test drive.
Does trouble repeat?
Repeat the
diagnosis it the
symptom or DTC
appears again
Go to
Step 1Go to Step 5
4Verify DTC through: ªF0: Diagnostic Trouble Codes.º
Is the DTC stored in the EHCU?
Clear code and
check for
repeatability
Go to
Step 3
Trouble diagnosis
based on
symptom (Refer
to
Symptom
Diagnosis
)
Go to
Step 3
51. Reconnect all components. Ensure that all component are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
FinishedGo to Step 5

5A±24BRAKE CONTROL SYSTEM
EHCU Connector Pin-out Checks

Disconnect Electronic Hydraulic Control Module.

Perform checks with high impedance digital
multimeter J-39200 or equivalent.
No.
Circuit to be TestedIgnition
Switch
PositionMultimeter
Scale/RangeMeasure
between Pin
NumberNominal ValueNote
1Power supplyOFF20DCV1 (C±5)
2 (C±5)11.5V to 14.5V
2Ignition enableOFF20DCV1 (C±6)
7 (C±6)0V to 0.1V
ON20DCV1 (C±6)
7 (C±6)11.5V to 14.5V
3Stoplamp switchOFF20DCV13 (C±6)
7 (C±6)10.5V to 14.5VPress brake pedal
4Ground connectionOFF200
7 (C±6)
GroundLess than 2

OFF1
2 (C±5)
GroundLess than 0.2

5FL speed sensorOFF2k
2 (C±6)
10 (C±6)2.0k
to 2.8k
Internal Resistance
OFF200k
2 (C±6)
7 (C±6)more than
100k
Insulation Resistance
OFF200mACV 2 (C±6)
10 (C±6)more than
200mVTurn wheel at 1RPS
6FR speed sensorOFF2k
3 (C±6)
11 (C±6)2.0k
to 2.8k
Internal Resistance
OFF200k
3 (C±6)
7 (C±6)more than
100k
Insulation Resistance
OFF200mACV 3 (C±6)
11 (C±6)more than
200mVTurn wheel at 1RPS
7RR speed sensorOFF2k
4 (C±6)
12 (C±6)1.2k
to 2.0k
Internal Resistance
OFF200k
4 (C±6)
7 (C±6)more than
100k
Insulation Resistance
OFF200mACV 4 (C±6)
12 (C±6)more than
200mVTurn wheel at 1RPS

5A±32BRAKE CONTROL SYSTEM
Chart A-3, TA-3 The Wheels Are Locked
StepActionYe sNo
1Is ABS working?Go to Step 2Go to Step 4
2Is vehicle speed under 10 km/h (6mph)?Go to Step 3Normal.
3Is sensor output normal? (Chart C-1 or TC-1)
Go to Step 4
Replace sensor
or repair harness.
Go to
Step 6
4Is front TOD control unit normal?
Go to Step 5
Replace TOD
control unit or
repair harness.
Go to
Step 6
5Is hydraulic unit grounded properly?Replace EHCU.
Go to
Step 6
Repair.
Go to
Step 6
6Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 6
Chart A-4 Brake Pedal Feed Is Abnormal
StepActionYe sNo
1Is the stop light actuated when the brake pedal is depressed?Go to Step 2Go to Step 3
21. Turn the ignition switch off.
2. Disconnected EHCU connector.
Is the check voltage EHCU connector terminals 13 to 7 when
brake pedal is depressed than battery voltage?
Go to Step 4
Harness NG
between brake
SW and EHCU.
Go to
Step 6
3Is stop light fuse normal?
Go to Step 5
Replace stop light
fuse.
Go to
Step 6
4Is the check continuity between EHCU connector terminals, 7 to
body grounded?
Go to Step 6
Repair body
grounded
harness.
Go to
Step 6
5Is brake SW normal?Repair stop light
harness.
Go to
Step 6
Replace brake
SW.
Go to
Step 6
6Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 6

5A±34BRAKE CONTROL SYSTEM
Diagnostic Trouble Codes
Choose and trace an appropriate flowchart by the
numbers listed below to find fault and repair.
Code
ChartFlash outSerial
CommunicationsDiagnosisItemChart
No.
12ÐÐÐÐ
13C02852 WD Controller in 4WD Vehicle ControllerWiringB-8
14C0271RAM read/write error
C0272ROM checksum errorCoil
C0270ALU function error
Coil
Integrated
Mdl
B-2
C0273Inoperative isolation itemModule
C0284Loop time overrun
15C0277Low ignition voltageWiringB-3C0278High ignition voltageWiringB-3
17C0269Excessive dump timeB-4
18C0274Excessive isolation timeCoil
IntegratedB-5
21C0276G-Sensor FailureIntegrated
ModuleB-6
22C0281Brake switch FailureB-7
24C0282Open or shorted 4y4 input signal (4WD only)WiringB-8
32C0267Open motor circuit or shorted ECU outputMotorB-9C0268Stalled motor or open ECU outputMotorB-9
35C0265Open relay circuitRelayB-10C0266Shorted relay circuitRelayB-10
41C0245FL Open isolation solenoid or shorted ECU outputB-11C0247FL Shorted isolation solenoid or open ECU outputB-11
42C0246FL Open dump solenoid or shorted ECU outputB-12C0248FL Shorted dump solenoid or open ECU outputB-12
43C0241FR Open isolation solenoid or shorted ECU outputB-13C0243FR Shorted isolation solenoid or open ECU outputSolenoid
B-13
44C0242FR Open dump solenoid or shorted ECU outputSolenoid
B-14C0244FR Shorted dump solenoid or open ECU outputB-14
45C0251Rear Open isolation solenoid or shorted ECU outputB-15C0253Rear Shorted isolation solenoid or open ECU outputB-15
46C0252Rear Open dump solenoid or shorted ECU outputB-16C0254Rear Shorted dump solenoid or open ECU outputB-16

5A±36BRAKE CONTROL SYSTEM
Diagnosis By ªABSº Warning Light
Illumination Pattern
In the event that there is abnormality in the ªABSº warning
light illumination pattern while the key is in the ON position
or if the warning light is actuated while driving, refer to the
flow chart below for the correct diagnostic procedure.
No.
ConditionªABSº Warning Light Illumination PatternDiagnostic
1Warning light is
actuated normallyNormal
2Warning light is not litWarning light lighting circuit
trouble"Go to Chart B-1
3Warning light remains
ONDiagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.
4Warning light is
actuated while drivingDiagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.
5Warning light goes at
12 km/h (8 mph) or
higher (After repairing
the faulty part)Even after repairing the
faulty part the warning light
(W/L) dose not go out if
vehicle is at a stop.
Turn the ignition switch to the
ON position and drive the
vehicle at 12 km/h (8 mph) or
higher to make sure that the
warning light goes out.

5A±39
BRAKE CONTROL SYSTEM
Chart B-1 With the key in the ON position (Before starting the engine). Warning light (W/L)
is not activated.
StepActionYe sNo
1Is W/L fuse disconnected?Replace fuse.
Go to
Step 5Go to Step 2
2Is W/L burnt out?Replace W/L
bulb.
Go to
Step 5Go to Step 3
31. Turn the key off.
2. Disconnect coil integrated module connector (C-6).
3. Turn the key ON.
Is the check voltage between coil integrated module connector
(C-6) terminals 6 and 7 the battery voltage?
Go to Step 4
Repair harness
and connector.
Go to
Step 5
4Is there the continuity between coil integrated module connector
(C-6) terminals, 1 and 7 and body ground.Check harness
for suspected
disconnection
No fault found:
Replace EHCU.
Go to
Step 5
Repair harness
and connector.
Go to
Step 5
5Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 5
Chart B-2 CPU Error (DTC 14 (Flash out) / C0271, C0272, C0273, C0284 (Serial
communications))
StepActionYe sNo
11. Turn the key off.
2. Disconnected coil integrated module connector.
3. Inspect coil integrated module ground.
Is there the continuity between the coil integrated module
connector terminals, 2 (C-5) and 7 (C-6) and body ground?
Go to Step 2
Repair the body
ground harness.
Go to
Step 3
21. Turn the key off, connect the coil integrated module connector.
2. Erase the trouble code.
3. Turn Ignition off, then on, to perform system self-check.
4. If warning light remains on, display trouble codes once again.
Is the trouble code the DTC 14 (Flash out) / C0271, C0272,
C0273, C0284 (Serial communications)?
Replace EHCU.
Go to
Step 3
Inspect in
accordance with
the DTC
displayed.
31. Reconnect all components, ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat the ªBasic
diagnostic flow
chartº
Go to Step 3