2007 ISUZU KB P190 warning

BRAKE CONTROL SYSTEM 5A-25
“ABS” Warning Lamp
W hen ABS and problems occur that actuate the “ABS”
warning lamp, the code corresponding to the problem is
stored in the EHCU. Only ordinary braking is available
when the ABS is deactivated. Even when the “ABS”
warning lamp is actuated, if the starter switch is set ON
after setting it OFF once, the EHCU checks up on the
entire system. If there is no abnormality, the EHCU
judges ABS to work correctly and the warning lamp is lit
normally, even though the problem code is stored.
NOTE: Illumination of the “ABS” warning lamp indicates
that anti-lock braking is no longer available. Power
assisted braking without anti-lock control is still
available.

Normal Operation
“ABS ” Warning Lamp
W hen the ignition is first moved from “OFF” to “RUN”,
the amber “ABS” warning lamp will turn “ON”. The
“ABS” warning lamp will turn “ON” during engine
starting and will usually stay “ON” for approximately
three seconds after the ignition switch is returned to the
“ON” position. The warning lamp should remain “OFF”
at all other times.

Brake (EBD) Warning Lamp


RTW 75ASH000101
Vehicles equipped with the EBD (Electronic Brake-force
Distribution) System have a “Brake” warning lamp on
the instrument panel.
If the ABS warning lamp and Brake warning lamp are
turned "ON", then EBD has failed. ( Parking brake
switch is "OFF")
In the following conditions, the EBD warning lamp is
"ON".
• Starter switch is "ON", engine "OFF". ( Parking brake switch is "OFF")
If engine is started, then EBD warning lamp is "OFF".
( Parking brake switch is "OFF")



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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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ISUZU KB P190 2007

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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ISUZU KB P190 2007

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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ISUZU KB P190 2007

5A-38 BRAKE CONTROL SYSTEM
Basic Diagnostic Flow Chart



RTW 75ALF000201
Step Action Value(s) Yes No
1 1. Ignition “ON”, engine “OFF”.
2. Observe the ABS warning lamp. Note: If the starter switch is turned ON, the ABS
warning lamp will turn on and then turn off after 3
seconds.
Is the ABS warning lamp “ON”? - Go to Step 2 Go to “No
ABS warning lamp”
2 1. Ignition “OFF”.
2. Install Tech 2.
3. Ignition “ON”.
4. Attempt to display ABS data with the Tech 2. Does the Tech 2 display ABS data? - Go to Step 5 Go to Step 3

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ISUZU KB P190 2007

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

5A-46 BRAKE CONTROL SYSTEM
No ABS Warning Lamp

Step Action Value(s) Yes No
1 Check the meter fuse for the instrument cluster
ignition feed circuit.
Is the fuse OK? - Go to Step 3 Go to Step 2
2 Replace the fuse. Is the action complete? - Verify repair
Go to Step 3 -
3 1. Ignition “OFF”, disconnect the EHCU. 2. Ignition “ON”, engine “OFF”.
3. Observe the ABS warning lamp. Is the ABS warning lamp “ON”? - Go to Step 5 Go to Step 4
4 Repair or replace the meter circuit or meter.
Is the action complete? - Verify repair -
5 1. Check the EHCU circuit for an open, short to
ground, or short to voltage. Also, check the EHCU
ignition feed circuit for an open or short to ground
and the EHCU ground circuit for an open.
2. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 6
6 1. Ignition “OFF”, reconnect the EHCU.
2. Ignition “ON”,engine “OFF”.
3. Observe the ABS warning lamp. Is the ABS warning lamp “ON”? - Verify repair Go to Step 7
7 Replace EHCU.
Note: Check the EHCU type for specification, the
EHCU is replaced.
(Specification; 2W D or 4W D Model)
Is the action complete? - Verify repair -


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ISUZU KB P190 2007