2002 ISUZU AXIOM warning light

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±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±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±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.

5A±50BRAKE CONTROL SYSTEM
Chart B-22 Rear Speed Sensor Missing Signal (DTC 63 (Flash out) / C0236, C0237 (Serial
communications))
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Measure the Rear speed sensor resistance between coil
integrated module connector (C-6) terminals 4 and 12.
Is the resistance between 1.0k and 1.7k ohms?
Go to Step 2Go to Step 3
2Is there play sensor/sensor rotor?Repair.
Go to
Step 6Go to Step 4
3Measure the rear speed sensor resistance at the sensor
connector.
Is the resistance between 1.0k and 1.7k 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-1-3 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.