2002 ISUZU AXIOM light

5A±30BRAKE CONTROL SYSTEM
Symptom Diagnosis
The symptoms that cannot be indicated by warning light
can be divided in the following five categories:
1. ABS works frequently but vehicle does not
decelerate.
2. Uneven braking occurs while ABS works.
3. The wheels lock during braking.
4. Brake pedal feel is abnormal.
5. Braking sound (from EHCU) is heard while not
braking.
These are all attributed to problems which cannot be
detected by EHCU self-diagnosis. Use the customer
complaint and test to determine which symptom is
present. Then follow the appropriate flow chart listed
below.
NoSymptomDiagnostic Flow ChartsNo.Sym tomWithout TECH 2With TECH 2
1ABS works frequently but vehicle does not decelerate.Chart A-1Chart TA-1
2Uneven braking occurs while ABS works.Chart A-2Chart TA-2
3The wheels are locked.Chart A-3Chart TA-3
4Brake pedal feel is abnormal.Chart A-4Ð
5Braking sound (from EHCU) is heard while not braking. Chart A-5Chart TA-5
Chart A-1 ABS Works Frequently But Vehicle Does Not Decelerate
StepActionYe sNo
1Is braking force distribution normal between front and rear of
vehicle?
Go to Step 2
Repair brake
parts.
Go to
Step 7
2Are axle parts installed normally?
Go to Step 3
Repair axle parts.
Go to
Step 7
3Is there play in each or any wheel speed sensor?Repair wheel
speed sensor.
Go to
Step 7Go to Step 4
4Is there damage, or powdered iron sticking to each or any wheel
speed sensor/sensor ring?Replace or repair
sensor or sensor
ring.
Go to
Step 7Go to Step 5
5Is the output of each wheel speed sensor normal? (Refer to Chart
C-1 or TC-1
)
Go to Step 6
Replace wheel
speed sensor or
repair harness.
Go to
Step 7
6Is the input of TOD control unit normal?
Go to Step 7
Replace TOD
control unit or
repair harness.
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±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±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±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±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

5A±48BRAKE CONTROL SYSTEM
Chart B-20 FL Speed Sensor Missing Signal (DTC 61 (Flash out) / C0226, C0227 (Serial
communications))
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Measure the FL speed sensor resistance between coil
integrated module connector (C-6) terminals 2 and 10.
Is the resistance between 2.0k and 2.8k ohms?
Go to Step 2Go to Step 3
2Is there play sensor/sensor rotor?Repair.
Go to
Step 6Go to Step 4
3Measure the FL speed sensor resistance at the sensor connector.
Is the resistance between 2.0k and 2.8k ohms?Repair harness
abnormality
between sensors
and coil
integrated
module.
Go to
Step 6
Replace sensor.
Go to
Step 6
4Damage and powdered iron sticking to sensor/sensor ring?Repair.
Go to
Step 6Go to Step 5
5Is sensor output normal? (Chart C-1-1 or TC-1)Check for faults
in harness
between speed
sensor and coil
integrated
module.
Fault found:
repair, and
perform system
self-check.
No fault found:
replace EHCU.
Go to
Step 6
Replace sensor.
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
NOTE: Even after repairing the faulty part the warning
light (W/L) does not go out if the 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±49
BRAKE CONTROL SYSTEM
Chart B-21 FR Speed Sensor Missing Signal (DTC 62 (Flash out) / C0222, C0223 (Serial
communications))
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Measure the FR speed sensor resistance between coil
integrated module connector (C-6) terminals 3 and 11.
Is the resistance between 2.0k and 2.8k ohms?
Go to Step 2Go to Step 3
2Is there play sensor/sensor rotor?Repair.
Go to
Step 6Go to Step 4
3Measure the FR speed sensor resistance at the sensor
connector.
Is the resistance between 2.0k and 2.8k ohms?Repair harness
abnormality
between sensors
and coil
integrated
module.
Go to
Step 6
Replace sensor.
Go to
Step 6
4Damage and powered iron sticking to sensor/sensor ring?Repair.
Go to
Step 6Go to Step 5
5Is sensor output normal? (Chart C-1-2 or TC-1)Check for faults
in harness
between speed
sensor and coil
integrated
module.
Fault found:
repair, and
perform system
self-check.
No fault found:
replace EHCU.
Go to
Step 6
Replace sensor.
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
NOTE: Even after repairing the faulty part the warning
light (W/L) does not go out if the 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.