ISUZU KB P190 2007 Workshop Repair Manual

5A-28 BRAKE CONTROL SYSTEM
4. Check the EHCU part number. Press the "Confirm".





RTW 75ASH000501

5. Check a DTC is not detected. Press the "Confirm".




RTW 75ASH000601
6. According to indication of Tech 2 press the
"Confirm".





RTW 75ASH000701

7. According to indication of Tech 2 press the
"Confirm".




RTW 75ASH000801


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ISUZU KB P190 2007

BRAKE CONTROL SYSTEM 5A-29
8. According to indication of Tech 2 press the
"Confirm".





RTW 75ASH000901

9. According to indication of Tech 2 press the
"Confirm".






RTW 75ASH001001
10. According to indication of Tech 2 press the
"Confirm".






RTW 75ASH001101

Return Pump Relay Test
Test condition: Engine stops with the key turned to the
"ON" position. To be more specific, the test is
conducted with the brake pedal stepped on afte
r
stepping once and releasing.
Test Procedure: 1. Connect the Tech 2 with the vehicle, and selec
t
"Actuator Test" menus.
2. Select a " Return Pump Relay Test " menu from the "Actuator Test" menus.
The circuit is normal if the pump motor is operated in
accordance with Tech 2 instruction.

Front Left Hold Valve Test
Purpose: The purpose of this test is to detect brake pipe
and valve line harness wire for incorrect connections
and valve problem.
This test will help you confirm the result of your repai
r
service including the removal/ reinstallation of brake
pipe, valve line harness and valve.
Test conditions: The ignition key is in the "ON" position
with the four wheels lifted up. The brake pedal is
stepped on, released and stepped on again with the
parking brake released.

Test Procedure: 1. Connect Tech 2 with the vehicle, and selec
t
"Actuator Test" menus.
2. Select a "Front Left Hold Valve Test" menu from the "Actuator Test" menus.
3. Step on the brake pedal.


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ISUZU KB P190 2007

5A-30 BRAKE CONTROL SYSTEM
4. Release the brake pedal.
5. Make sure that the front left hold solenoid valve "ON" aimed at by Tech 2 and the wheel locked
position are the same.
If different, check brake pipe, valve line harness wiring
and hydraulic unit. Repair is needed if abnormality is
found.

Front Left Release Valve Test
Purpose: The purpose of this test is to detect brake pipe
and valve line harness wire for incorrect connections and
valve problem.
This test will help you confirm the result of your repai
r
service including the removal/ reinstallation of brake
pipe, valve line harness and valve.
Test conditions: The ignition key is in the "ON" position
with the four wheels lifted up. The brake pedal is stepped
on, released and stepped on again with the parking
brake released.

Test Procedure: 1. Connect Tech 2 with the vehicle, and select "Actuator Test" menus.
2. Select a "Front Left Release Valve Test" menu from the "Actuator Test" menus.
3. Step on the brake pedal.
4. Make sure that the front left release solenoid valve "ON" aimed at by Tech 2 and the wheel released
position are the same.
If different, check brake pipe, valve line harness wiring
and hydraulic unit. Repair is needed if abnormality is
found.

Front Right Hold Valve Test
Purpose: The purpose of this test is to detect brake pipe
and valve line harness wire for incorrect connections and
valve problem.
This test will help you confirm the result of your repai
r
service including the removal/ reinstallation of brake
pipe, valve line harness and valve.
Test conditions: The ignition key is in the "ON" position
with the four wheels lifted up. The brake pedal is stepped
on, released and stepped on again with the parking
brake released.

Test Procedure: 1. Connect Tech 2 with the vehicle, and select "Actuator Test" menus.
2. Select a "Front Right Hold Valve Test" menu from the "Actuator Test" menus.
3. Step on the brake pedal.
4. Release the brake pedal.
5. Make sure that the front right hold solenoid valve "ON" aimed at by Tech 2 and the wheel locked
position are the same.
If different, check brake pipe, valve line harness wiring
and hydraulic unit. Repair is needed if abnormality is
found.

Front Right Release Valve Test
Purpose: The purpose of this test is to detect brake pipe
and valve line harness wire for incorrect connections
and valve problem.
This test will help you confirm the result of your repai
r
service including the removal/ reinstallation of brake
pipe, valve line harness and valve.
Test conditions: The ignition key is in the "ON" position
with the four wheels lifted up. The brake pedal is
stepped on, released and stepped on again with the
parking brake released.

Test Procedure: 1. Connect Tech 2 with the vehicle, and selec
t
"Actuator Test" menus.
2. Select a "Front Right Release Valve Test" menu from the "Actuator Test" menus.
3. Step on the brake pedal.
4. Make sure that the front right release solenoid valve "ON" aimed at by Tech 2 and the wheel released
position are the same.
If different, check brake pipe, valve line harness wiring
and hydraulic unit. Repair is needed if abnormality is
found.

Rear Hold Valve Test
Purpose: The purpose of this test is to detect brake pipe
and valve line harness wire for incorrect connections
and valve problem.
This test will help you confirm the result of your repai
r
service including the removal/ reinstallation of brake
pipe, valve line harness and valve.
Test conditions: The ignition key is in the "ON" position
with the four wheels lifted up. The brake pedal is
stepped on, released and stepped on again with the
parking brake released.

Test Procedure: 1. Connect Tech 2 with the vehicle, and selec
t
"Actuator Test" menus.


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ISUZU KB P190 2007

BRAKE CONTROL SYSTEM 5A-31
2. Select a "Rear Hold Valve Test" menu from the
"Actuator Test" menus.
3. Step on the brake pedal.
4. Release the brake pedal.
5. Make sure that the rear hold solenoid valve "ON" aimed at by Tech 2 and the wheel locked position
are the same.
If different, check brake pipe, valve line harness wiring
and hydraulic unit. Repair is needed if abnormality is
found.

Rear Release Valve Test
Purpose: The purpose of this test is to detect brake pipe
and valve line harness wire for incorrect connections and
valve problem.
This test will help you confirm the result of your repai
r
service including the removal/ reinstallation of brake
pipe, valve line harness and valve.
Test conditions: The ignition key is in the "ON" position
with the four wheels lifted up. The brake pedal is stepped
on, released and stepped on again with the parking
brake released.

Test Procedure: 1. Connect Tech 2 with the vehicle, and select "Actuator Test" menus.
2. Select a "Rear Release Valve Test" menu from the "Actuator Test" menus.
3. Step on the brake pedal.
4. Make sure that the rear release solenoid valve "ON" aimed at by Tech 2 and the wheel released position
are the same.
If different, check brake pipe, valve line harness wiring
and hydraulic unit. Repair is needed if abnormality is
found.


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ISUZU KB P190 2007

5A-32 BRAKE CONTROL SYSTEM
Data List (Tech 2)
The data displayed by DATA LIST are as follows:
Strings Units Description
FL W heel Speed (Front Left) Km/h (MPH)
FR W heel Speed (Front Right) Km/h (MPH)
RL W heel Speed (Rear Left) Km/h (MPH)
RR W heel Speed (Rear Right) Km/h (MPH) Start the vehicle and make sure of linear
change in each wheel speed.
Brake Switch On/Off Brake switch is “On” when brake pedal is stepped
on.
4 W heel Drive Status 2 W heel Drive/
4 W heel Drive
ABS W arning lamp
On/Off To be “Off” usually
EBD W arning Lamp On/Off To be “Off” usually
ABS State On/Off To be “Off” usually
Valve Relay Command Active/Inactive To be “Active” usually
Return Pump Relay Command Active/Inactive To be “Inactive” usually
EBD State
DTC Status No DTC/
DTCs Set To be “No DTC” usually
FL Release Solenoid Commanded
(Front Left) Active/Inactive
FL Hold Solenoid Commanded (Front
Left) Active/Inactive
FR Release Solenoid Commanded
(Front Right) Active/Inactive
FR Hold Solenoid Commanded (Front
Right) Active/Inactive
Rear Release Solenoid Valve
Commanded Active/Inactive
Rear Hold Solenoid Valve Commanded Active/Inactive
FL Release Solenoid Feedback (Front
Left) Active/Inactive
FL Hold Solenoid Feedback (Front Left) Active/Inactive
FR Release Solenoid Feedback (Front
Left) Active/Inactive
FR Hold Solenoid Feedback (Front Left) Active/Inactive
Rear Release Solenoid Feedback Active/Inactive
Rear Hold Solenoid Valve Feedback Active/Inactive Each valve is “Active” when each valve is operated.
Deceleration Sensor
V 2.0~3.0V when vehicle speed is 0km/h (flat place)
Battery Voltage V The voltage value currently supplied to EHCU


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ISUZU KB P190 2007

BRAKE CONTROL SYSTEM 5A-33
Diagnostic Trouble Codes
Choose and trace an appropriate flowchart by the
numbers listed below to find the fault and repair.
Note:
A DTC cannot be erased when the DTC is present.
Warning Lamp System Control Main Items
DTC
(Flash Code) Description
ABS Brake
(EBD) ABS EBD

-
(12) Normal Condition
× × -
C0221
(21) Front Right W heel Speed Sensor
Short Circuit or Circuit Open ×*A × Sensor or W iring
C0222
(22) Front Right W heel Speed Sensor
Signal Malfunction *B ×*A × Sensor or install condition
C0225
(25) Front Left W heel Speed Sensor Short
Circuit or Circuit Open ×*A × Sensor or W iring
C0226
(26) Front Left W heel Speed Sensor Signal
Malfunction *B ×*A × Sensor or install condition
C0231
(31) Rear Right W heel Speed Sensor Short
Circuit or Circuit Open ×*A × Sensor or W iring
C0232
(32) Rear Right W heel Speed Sensor
Signal Malfunction *B ×*A × Sensor or install condition
C0235
(35) Rear Left W heel Speed Sensor Short
Circuit or Circuit Open ×*A × Sensor or W iring
C0236
(36) Rear Left W heel Speed Sensor Signal
Malfunction *B ×*A × Sensor or install condition
C0238
(38) Front Speed Sensor Correlation
× × Vehicle , Sensor or Tire
C0241
(41) Front Right Hold Solenoid Valve Circuit
× × Solenoid (EHCU)
C0242
(42) Front Right Release Solenoid Valve
Circuit × × Solenoid (EHCU)
C0245
(45) Front Left Hold Solenoid Valve Circuit
× × Solenoid (EHCU)
C0246
(46) Front Left Release Solenoid Valve
Circuit × × Solenoid (EHCU)
C0251
(51) Rear Hold Solenoid Valve Circuit
× × Solenoid (EHCU)
C0252
(52) Rear Release Solenoid Valve Circuit
× × Solenoid (EHCU)
×
C0265
(65) Valve Relay Circuit Malfunction
×

× Relay (EHCU)
C0267
(67) Return Pump Circuit Malfunction
× Motor (EHCU)
C0271
(71) ECU Malfunction
× × EHCU
C0276
(76) G Sensor Malfunction
× × Sensor or W iring

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5A-34 BRAKE CONTROL SYSTEM
Warning Lamp System Control Main Items DTC
(Flash Code) Description
ABS Brake
(EBD) ABS EBD


× × Battery, W iring or EHCU
(less than 8V) C0277 (77) System Voltage Low

× × Battery or W iring
(less than 10V)
C0278 (78) System Voltage High
× × Battery or W iring EHCU
C0282
(82) 4 W heel Drive State Input Signal
Failure × × W iring
C0285
(85) Control Module Vehicle Options
Incorrect × × Vehicle (Sensor or EHCU)

*A : W hen three or more failures are detected, the EBD warning lamp is "ON" and control is canceled.
*B : The ABS lamp is “OFF” when the ABS lamp is “ON” after a repair, until the vehicle’s speed becomes
more than 10km/h (6mph) in the following ignition
cycle and failure is not detected.


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ISUZU KB P190 2007

BRAKE CONTROL SYSTEM 5A-35
Diagnosis By “ABS” Warning Lamp
Illumination Pattern
In the event that there is abnormality in the “ABS”
W arning Lamp Illumination Pattern while the key is in
the “ON” position or if the warning lamp is actuated
during driving, the fault should be diagnosed on an
illumination pattern basis as follows:

No. Condition “ABS” Warning Lamp Illumination Pattern Diagnostic
1 W arning Lamp is
actuated normally
Normal
2 W arning Lamp is not
lit
W arning Lamp lighting circuit
trouble. Go to No ABS
W arning Lamp.
3 W arning Lamp remains ON
Diagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.
If diagnostic trouble codes are
not stored, it means warning
lamp lighting circuit or meter
trouble. Go to ABS warning
Lamp On Steady.
4 W arning Lamp is actuated while driving
Diagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.
Diagnostic Trouble Codes (DTCs)
W hen the warning lamp in the meter remains ON, the
EHCU stores the fault identification and disables the
ABS.



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5A-36 BRAKE CONTROL SYSTEM
How to display and erase DTCs:
Note:
• DTCs can be displayed also by TECH 2 use “Diagnostic Trouble Codes” 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 conditions are satisfied, the
DTC display cannot be started.)
• W ith 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
















This illustration is based on RHD model
350L300005

• 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 lamp.
• 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 pedal depressed).

B05RW 0005

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BRAKE CONTROL SYSTEM 5A-37
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
Display of DTC 23

B05R100001
After displaying DTC 12 three times, one DTC after
another is displayed. DTC is displayed in numeric
order.
C05L300017
The DTC 12 is displayed repeatedly.




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