ISUZU AXIOM 2002 Service Repair Manual

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±23
BRAKE CONTROL SYSTEM
Basic Inspection Procedure
1. Basic Inspection of Service Brake
StepActionYe sNo
1Is the fluid level normal?
Go to Step 2
Replenish with
fluid
Go to
Step 2
2Does fluid leak?Repair
Go to
Step 3Go to Step 3
3Is the booster functioning properly?
Go to Step 4
Repair
Go to
Step 4
4Is the pad and rotor within specs?
Go to Step 5
Repair
Go to
Step 5
5Reconnect all components. Ensure all component are properly
mounted.
Was this step finished?
FinishedGo to Step 5
2. Ground Inspection
StepActionYe sNo
1Is there good contact with the ABS ground points?
Go to Step 2
Repair
Go to
Step 2
2Reconnect all components. Ensure that all component are
properly mounted.
FinishedGo to Step 2

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±25
BRAKE CONTROL SYSTEM
Circuit Diagram
D05R200004

5A±26BRAKE CONTROL SYSTEM
D05R200002

5A±27
BRAKE CONTROL SYSTEM
D05R200003

5A±28BRAKE CONTROL SYSTEM
Connector List
No.Connector face
B-15
C-1
C-28
C-5
C-6
C-10
C-16
E-23
C-27
C-37
C-39
F-4
No.Connector face
H-5
H-8
H-14
H-16
H-20
I-18
I-23
I-24
X-15

5A±29
BRAKE CONTROL SYSTEM
Part Location
810R200002
Legend
(1) Battery
(2) Fuse & Relay Box
(3) C±16
(4) C±5
(5) C±6
(6) H±8, 14
(7) I±18
(8) Starter Switch(9) I±24
(10) C±39
(11) F±4
(15) C±10
(16) C±28
(17) H±5
(19) E±23
(21) C±1

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±31
BRAKE CONTROL SYSTEM
Chart TA-1 ABS Works Frequently But Vehicle Does Not Decelerate (Use TECH 2)
StepActionYe sNo
11. Connect TECH 2.
2. Make sure of the output conditions of each sensor.
Is the output of each sensor normal?
Go to Step 2
Replace wheel
speed sensor.
Go to
Step 3
2Return to Chart A-1.
Was the Chart A-1 finished?
Go to Step 3Go to Step 2
3Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 3
Chart A-2 Uneven Braking Occurs While ABS Works
StepActionYe sNo
1Is there play in each or any sensor?Repair.
Go to
Step 5Go to Step 2
2Damage or powdered iron sticking to each or any sensor/sensor
ring?Repair.
Go to
Step 5Go to Step 3
3Is the output of each sensor normal? (Refer to Chart C-1 or TC-1)
Go to Step 4
Replace sensor
or repair harness.
Go to
Step 5
4Is brake pipe connecting order correct?
Replace H/U.
Go to
Step 5
Reconnect brake
pipe correctly.
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 TA-2 Uneven Braking Occurs While ABS Works (Use TECH 2)
StepActionYe sNo
11. Connect TECH 2.
2. Make sure of the output conditions of each sensor.
Is the output of each sensor normal?
Go to Step 2Go to Step 3
2Check piping by TECH 2 ACTUATOR TEST
Is the piping normal?Replace EHCU.
Go to
Step 4
Repair the pipe.
Go to
Step 4
3Repair and check the wheel speed sensor (Refer to Chart B-20 to
B-23 , C-1 or TC-1
).
Was the each chart finished?
Go to Step 4Go to Step 3
4Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 4