ISUZU AXIOM 2002 Service Repair Manual

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±33
BRAKE CONTROL SYSTEM
Chart A-5, TA-5 Braking Sound (From EHCU) Is Heard While Not Braking
StepActionYe sNo
1Is this the first vehicle start after engine start?Normal.
(It is self
checking sound.)
Go to Step 2
2Is vehicle speed under 10 km/h (6 mph)?Normal.
(It is self
checking sound.)
Go to Step 3
3Check for the following condition:

At the time of shift down or clutch operation.

At the time of low road friction drive (ice or snow road) or rough
road drive.

At the time of high-speed turn.

At the time of passing curb.

At the time of operating electrical equipment switches.

At the time of racing the engine (over 5000 rpm).
Did it occur under any one condition above?
ABS may
sometimes be
actuated even
when brake pedal
is not applied.
Go to Step 4
4Is there play in each or any sensor/wheel speed sensor rings?Repair.
Go to
Step 7Go to Step 5
5Damage or powdered iron sticking to each or any sensor/wheel
speed sensor ring?Repair.
Go to
Step 7Go to Step 6
6Is each sensor output normal? (Refer to Chart C-1 or TC-1).Check harness/
connector for
suspected
disconnection
If no
disconnection is
found, replace
Coil integrated
module.
Go to
Step 7
Repair.
Go to
Step 7
7Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 7

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±35
BRAKE CONTROL SYSTEM
Code
Chart
No. Item Diagnosis
Flash outChart
No. Item Diagnosis
Serial
Communications
51C0225FL Open or shorted sensorB-17
52C0221FR Open or shorted sensorB-18
53C0235Rear Open or shorted sensorB-19
61C0226FL Missing sensor signalB-20C0227FL Sensor signal dropoutSensor or
B-20
62C0222FR Missing sensor signalWiring
B-21C0223FR Sensor signal dropoutB-21
63C0236Rear Missing sensor signalB-22C0237Rear Sensor signal dropoutB-22
64C0229Simultaneous dropout of front sensor signalB-23
65C0238Wheel speed errorVehicle or
SensorB-24
ÐC0286Shorted indicator lampWiringÐ

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±37
BRAKE CONTROL SYSTEM
Diagnostic Trouble Codes (DTCs)
When the warning light in the meter remains ON, the
EHCU stores the fault identification and disables the
ABS.
How to display and erase DTCs:
NOTE:

DTCs can be displayed also by TECH 2. Use
ªDiagnostic Trouble Codesº mode.1. How to start DTC display:

Confirm that the vehicle has come to a complete
stop (with the wheels standing still) and that the
brake pedal is not depressed. (Unless these two
condition are satisfied, DTC display cannot be
started.)

With IGN OFF, connect #12 terminal with #4
terminal or # 5 terminal (GND) . Then turn IGN ON.
The DLC is located behind the driver side kick panel
350R200001

Keep #12 terminal connected with #4 terminal or # 5
terminal (GND) during DTC display. (If #12 terminal
is separated from #4 terminal or # 5 terminal (GND)
during display, display will stop.)
2. DTC display:

DTC is displayed by blinking warning light.

Double-digit display.

First, normal DTC 12 is displayed three times and
then any other DTCs are displayed three times. (If
no other DTCs have been stored, the display of DTC
12 will be repeated.)3. How to erase code:

Conduct brake switch ON/OFF operation 6 or more
times within 3 seconds of self-diagnosis startup.

The code cannot be erased if more than 3 seconds
have passed since self-diagnosis startup, or if
self-diagnosis has started with brake switched on
(brake pedaled).
B05RW005

5A±38BRAKE CONTROL SYSTEM
4. Notes

If the following should occur during Diagnostic
Trouble Code (DTC) display, the display will be
discontinued. After initial check, the status that is
under the control of ABS will be returned :
± The vehicle starts (The wheels turn) or the brake
pedal is depressed.

Up to 3 different codes can be stored.

If the ABS should turn OFF due to an intermittent
defect, the system will be restored at the next key
cycle, if the initial check finds no abnormality (when
IGN is switched from OFF to ON).
5. An example of DTC display
B05R100001
After displaying DTC 12 three times, one DTC after
another is displayed, starting with the most recent
one. (However, display is discontinued after about 5
minutes.)
B05R100002
The DTC 12 is displayed repeatedly. (display is
discontinued after about 5 minutes after)

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

5A±40BRAKE CONTROL SYSTEM
Chart B-3 Low or High Ignition Voltage (DTC 15 (Flash out) / C0277, 0278 (Serial
communications))
StepActionYe sNo
1Is the battery voltage normal? (Battery capacity check)
Go to Step 2
Charge or
replace battery.
Go to
Step 2
21. Turn the key off.
2. Disconnect coil integrated module connector.
3. Turn the key on.
Is the voltage between coil integrated module connector (C-6)
terminals 1 and 7, higher than 10V?Check harness
connector for
suspected
disconnection
Fault found:
Repair, and
perform system
self-check
No fault found:
replace EHCU.
Go to
Step 3
Repair harness or
connector.
Go to
Step 3
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
Chart B-4 Excessive Dump Time (DTC 17 (Flash out) / C0269 (Serial communications))
StepActionYe sNo
1Check for anything causing extended ABS activation, such as
locked brakes or an erratic speed sensor signal.
Was a problem found?
Repair or
Replace
Go to Step 2
21. The key turned off.
2. Replace EHCU.
3. Reconnect all components, ensure all components are
properly mounted.
Was this step finished?
Repeat the ªBasic
diagnostic flow
chartº
Go to Step 2
Chart B-5 Excessive Isolation Time (DTC 18 (Flash out) / C0274 (Serial communications))
StepActionYe sNo
1Check for anything causing extended ABS activation, such as
locked brakes or an erratic speed sensor signal.
Was a problem found?
Repair or
Replace
Go to Step 2
21. The key turned off.
2. Replace EHCU.
3. Reconnect all components, ensure all components are
properly mounted.
Was this step finished?
Repeat the ªBasic
diagnostic flow
chartº
Go to Step 2

5A±41
BRAKE CONTROL SYSTEM
Chart B-6 G-Sensor Output Failure (DTC 21 (Flash out) / C0276 (Serial communications))
StepActionYe sNo
11. Turn the key off.
2. Replace EHCU.
3. Reconnect all components, ensure all components are
properly mounted.
Was this step finished?
Repeat the ªBasic
diagnostic flow
chartº
Go to Step 1
Chart B-7 Brake Switch Failure (DTC 22 (Flash out) / C0281 (Serial communications))
StepActionYe sNo
1Is the stop light actuated when the brake pedal is depressed?Go to Step 2Go to Step 4
21. Turn the key off.
2. Disconnected coil integrated module connector.
Is the check voltage between coil integrated module connector
(C-6) terminals 13 to 7 when brake pedal is depressed the battery
voltage?
Go to Step 3
Harness between
brake SW and
coil integrated
module is faulty.
Go to
Step 6
3Is the check that pins C-5 connector 2, and C-6 connector 7 have
good ground?Check harness /
connector for
disconnection
Fault found:
Repair, and
perform system
self-check.
No fault found:
replace EHCU.
Go to
Step 6
Repair.
Go to
Step 6
4Is stop light fuse normal?
Go to Step 5
Replace.
Go to
Step 6
5Is brake SW normal?Abnormal
harness in stop
light circuit.
Repair the
harness.
Go to
Step 6
Replace.
Go to
Step 6
61. 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 6