Page 634 of 6020
BRAKE CONTROL SYSTEM 5A-41
Wheel Speed Sensor Inspection Procedure
Procedure
1.Ignition "OFF".
2.Disconnect each of the wheel speed sensors.
3.Connect the resistance (50 Ω~100 Ω) as follows.
4.Check the voltage at sensor harness connector.
Note: Voltage measurement is performed in the phase
where the wheel speed sensor is installed in vehicles.
RTW 75AMF000701
Connector Pin-outs
・Front W heel Speed Sensor
1 (+) (+12V)
2 (-) (signal)
・Rear W heel Speed Sensor
1 LH (+) (+12V)
2 LH (-) (signal)
3 RH (+)(+12V)
4 RH (-) (signal)
Output Value
High State 0.7~1.4V (±30%)
Low State 0.4~0.7V (±30%)
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Page 635 of 6020

5A-42 BRAKE CONTROL SYSTEM
Symptom Diagnosis
The symptoms that cannot be indicated by warning
lamp can be divided into the following six categories:
1. ABS works frequently but vehicle does not decelerate.
2. Uneven braking occurs while ABS works.
3. The wheels are locked.
4. Brake pedal feel is abnormal.
5. Braking sound (from EHCU) is heard while not braking.
6. No ABS warning lamp
These are all attributable to problems which cannot be
detected by EHCU self-diagnosis. Use the customer
complaint and a test to determine which symptom is
present.
ABS Works Frequently But Vehicle Does Not Decelerate
Step Action Value(s) Yes No
1 Is braking force distribution normal between front and
rear of vehicle?
- Go to Step 2 Repair brake
parts.
Go to Step 7
2 Are axle parts installed normally?
- Go to Step 3 Repair axle
parts.
Go to Step 7
3 Is there play in each or any wheel speed sensor?
- Repair wheel
speed sensor.
Go to Step 7 Go to Step 4
4 Is there damage, or powered iron sticking to each or any wheel speed sensor/sensor rotor?
- Replace
wheel speed sensor or
sensor rotor.
Go to Step 7 Go to Step 5
5 Is the speed sensor of each wheel output normal?
- Go to Step 6 Replace
wheel speed sensor or repair
harness.
Go to Step 7
6 Is the 4W D control system function normal?
- 2-4W D Repair
or Go to Step 7 Repair or
replace 2-
4W D control System.
Go to Step 7
7 Reconnect all components, ensure all components are properly mounted.
Is this step finished? - Repeat the
“Basic
diagnostic
flow chart” Go to Step 7
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ISUZU KB P190 2007
Page 636 of 6020

BRAKE CONTROL SYSTEM 5A-43
Uneven Braking Occurs While ABS Works
Step Action Value(s) Yes No
1 Is there play in each or any sensor?
- Repair.
Go to Step 5 Go to Step 2
2 Damage or powdered iron sticking to each or any
sensor/sensor rotor? - Repair.
Go to Step 5 Go to Step 3
3 Is the output normal for each sensor?
- Go to Step 4 Replace
sensor or repair
harness.
Go to Step 5
4 Is brake pipe connecting order correct? Note: Check the EHCU type for specification, when
the EHCU is replaced.
(Specification; 2W D Model or 4W D Model) - Replace
EHCU.
Go to Step 5 Reconnect
brake pipe correctly.
Go to Step 5
5 Reconnect all components, ensure all components are properly mounted.
Is this step finished? - Repeat the
“Basic
diagnostic
flow chart” Go to Step 5
The Wheels Are Locked
Step Action Value(s) Yes No
1 Is ABS working?
- Go to Step 2 Go to Step 4
2 Is vehicle speed under 5 km/h? - Go to Step 3 Normal.
3 Is the output for each normal?
- Go to Step 4 Replace
sensor or repair
harness.
Go to Step 6
4 Is 2-4W D system function normal?
- Go to Step 5 Replace 2-
4W D control
unit or repair harness.
Go to Step 6
5 Is EHCU grounded properly? Note: Check the EHCU type for specification, when
the EHCU is replaced.
(Specification; 2W D Model or 4W D Model) - Replace
EHCU.
Go to Step 6 Repair.
Go to Step 6
6 Reconnect all components, ensure all components are properly mounted.
Is this step finished? - Repeat the
“Basic
diagnostic
flow chart” Go to Step 6
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ISUZU KB P190 2007
Page 638 of 6020

BRAKE CONTROL SYSTEM 5A-45
Braking Sound (From EHCU) Is Heard While Not Braking
Step Action Value(s) Yes No
1 Is this the first vehicle start after engine start?
- It is self
checking sound
Normal. Go to Step 2
2 Is vehicle speed at 15 km/h or 30 km/h?
- It is self
checking sound
Normal. Go to Step 3
3 Check for the following condition: • At the time of shift down or clutch operation.
• At the time of low road friction drive (ice or snow on 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. Did it occur under any of the conditions above? - ABS may
sometimes be
actuated even when brake pedal is not applied. Go to Step 4
4 Is there play in each or any sensor/wheel speed sensor rotor? - Repair.
Go to Step 7 Go to Step 5
5 Damage or powdered iron sticking to each or any sensor/wheel speed sensor rotor? - Repair.
Go to Step 7 Go to Step 6
6 Is each sensor normal? Note: Check the EHCU type for specification, the
EHCU is replaced.
(Specification; 2W D or 4W D Model)
- Check
harness/
connector for suspected
disconnection
If no
disconnection is found,
replace EHCU
Go to Step 7 Repair.
Go to Step 7
7 Reconnect all components, ensure all components are properly mounted.
Is this step finished? - Repeat the
“Basic
diagnostic
flow chart” Go to Step 7
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ISUZU KB P190 2007
Page 641 of 6020
5A-48 BRAKE CONTROL SYSTEM
DTC C0221 (Flash Code 21) Front Right Wheel Speed Sensor Short Circuit or
Circuit Open
RTW 75AMF001301
Step Action Value(s) Yes No
1 W ere the steps of the “Basic Diagnostic Flow Chart”
performed?
- Go to Step 2 Go to Basic
Diagnostic
Flow Chart
2 1. Check for a poor connection at the front right wheel speed sensor harness connector.
2. Check installation condition for front right wheel speed sensor.
3. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 3
3 1. Ignition “OFF”, disconnect the EHCU and front right
wheel speed sensor.
2. Check the circuit between EHCU and front right wheel speed sensor. (Circuit for an open, short to
ground, or short to voltage.)
3. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 4
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ISUZU KB P190 2007
Page 642 of 6020
BRAKE CONTROL SYSTEM 5A-49
Step Action
Value(s) Yes No
4 1. Replace front right wheel speed sensor.
2. Select “Display DTCs” with the Tech 2. Note: Perform the various tests (actuator test, test
run, brake test, etc.) then observe the DTC with a
Tech 2.
Are any DTCs stored? - Go to Step 5 Verify repair
5 Replace EHCU.
Note: Check the EHCU type for specification, when
the EHCU is replaced.
(Specification ; 2W D model or 4W D model)
Is the action complete? - Verify repair -
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ISUZU KB P190 2007
Page 643 of 6020
5A-50 BRAKE CONTROL SYSTEM
DTC C0222 (Flash Code 22) Front Right Wheel Speed Sensor Signal
Malfunction
RTW 75AMF001301
Step Action Value(s) Yes No
1 W ere the steps of the “Basic Diagnostic Flow Chart” performed?
- Go to Step 2 Go to Basic
Diagnostic
Flow Chart
2 1. Check the tire for the following conditions.
• Tire specification
• W ear of the outer surface
2. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 3
3 Note:
This DTC is set when certain tire is rotated alone.
Has certain tire been rotated alone by performing for
lift-up or roller tester? - Verify repair Go to Step 4
4 Is the front right wheel bearing rattling?
- Go to Step 11 Go to Step 5
5 Is the front right wheel speed sensor or the sensor
rotor rattling? - Go to Step 12 Go to Step 6
6 Is iron powder attached to the front right wheel speed
sensor or the sensor rotor? - Go to Step 13 Go to Step 7
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ISUZU KB P190 2007
Page 644 of 6020

BRAKE CONTROL SYSTEM 5A-51
Step Action Value(s) Yes No
7 Check the front right wheel speed sensor. Refer to
"W heel Speed Sensor Inspection procedure"
W as a problem found? - Go to Step 10 Go to Step 8
8 Does the sensor rotor have missing tooth or saw- toothed? - Go to Step 14 Go to Step 9
9 1. Clear the DTC.
2. Test run the vehicle, and check the DTC. Is the DTC displayed repeatedly? - Go to Step 18 Go to Step 17
10 Is the wheel speed sensor damaged or saw-toothed?
- Go to Step 15 Go to Step 16
11 Adjust the preload of the wheel bearing.
Is the action complete? - Verify repair -
12 Repair or replace the front right speed sensor or the
sensor rotor.
Is the action complete? - Verify repair -
13 Repair the front right speed sensor or the sensor rotor.
Is the action complete? - Verify repair -
14 Replace the sensor rotor. Is the action complete? - Verify repair -
15 Replace the front right wheel speed sensor.
Is the action complete? - Verify repair -
16 Repair or replace the front right speed sensor
circuits.
Is the action complete? - Verify repair -
17 Check the connection btween the EHCU and the front right wheel speed sensor and repair as
necessary Refer to "Note on Intermittents".
Is the action complete? - Verify repair -
18 Replace EHCU.
Note: Check the EHCU type for specification, when
the EHCU is replaced.
(Specification ; 2W D model or 4W D model)
Is the action complete? - Verify repair -
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ISUZU KB P190 2007