wheel ISUZU TF SERIES 2004 Workshop Manual

5A-30 BRAKE CONTROL SYSTEM

Diagnostic Trouble Codes
Choose and trace an appropriate flowchart by the
numbers listed below to find fault and repair.
Note:
DTC cannot be erased when the DTC is a present.

Warning Lamp System Control Main Items
DTC
(Flash
Code) Description
ABS Brake
(EBD)ABS EBD
-
(12) Normal Condition




-
C0221
(21) Front Right Wheel Speed Sensor Short
Circuit or Circuit Open

*A

Sensor or Wiring
C0222
(22) Front Right Wheel Speed Sensor
Incorrect Signal *B

A

Sensor or install condition
C0223
(23) Front Right Wheel Speed Sensor Signal
- Tooth Chipping

*A

Sensor Rotor or install
condition
C0225
(25) Front Left Wheel Speed Sensor Short
Circuit or Circuit Open

*A

Sensor or Wiring
C0226
(26) Front Left Wheel Speed Sensor
Incorrect Signal *B

*A

Sensor or install condition
C0227
(27) Front Left Wheel Speed Sensor Signal -
Tooth Chipping

*A

Sensor Rotor or install
condition
C0231
(31) Rear Right Wheel Speed Sensor Short
Circuit or Circuit Open

*A

Sensor or Wiring
C0232
(32) Rear Right Wheel Speed Sensor
Incorrect Signal *B

*A

Sensor or install condition
C0233
(33) Rear Right Wheel Speed Sensor Signal
- Tooth Chipping

*A

Sensor Rotor or install
condition
C0235
(35) Rear Left Wheel Speed Sensor Short
Circuit or Circuit Open

*A

Sensor or Wiring
C0236
(36) Rear Left Wheel Speed Sensor
Incorrect Signal *B

*A

Sensor or install condition
C0237
(37) Rear Left Wheel Speed Sensor Signal -
Tooth Chipping

*A

Sensor Rotor or install
condition
C0238
(38) Tire Diameter Error



Vehicle , Sensor or Tire
C0241
(41) Front Right Isolation Solenoid Circuit
Open or Shorted to Ground



Solenoid (EHCU)
C0242
(42) Front Right Dump Solenoid Circuit
Open or Shorted to Ground



Solenoid (EHCU)
C0243
(43) Front Right Isolation Solenoid Circuit
Shorted to Battery



Solenoid (EHCU)
C0244
(44) Front Right Dump Solenoid Circuit
Shorted to Battery



Solenoid (EHCU)
C0245
(45) Front Left Isolation Solenoid Open Or
Shorted to Ground



Solenoid (EHCU)
C0246
(46) Front Left Dump Solenoid Circuit Open
Or Shorted to Ground



Solenoid (EHCU)
C0247
(47) Front Left Isolation Solenoid Circuit
Shorted to Battery



Solenoid (EHCU)

BRAKE CONTROL SYSTEM 5A-31

Warning Lamp System Control Main Items DTC
(Flash
Code) Description
ABS Brake
(EBD)ABS EBD
C0248
(48) Front Left Dump Solenoid Circuit
Shorted to Battery



Solenoid (EHCU)
C0251
(51) Rear Isolation Solenoid Circuit Open or
Shorted to Ground



Solenoid (EHCU)
C0252
(52) Rear Dump Solenoid Circuit Open or
Shorted to Ground



Solenoid (EHCU)
C0253
(53) Rear Isolation Solenoid Circuit Shorted
to Battery



Solenoid (EHCU)
C0254
(54) Rear Dump Solenoid Circuit Shorted to
Battery



Solenoid (EHCU)
C0265
(65) Fail Safe Relay (FSR) Shorted to
Ground



Motor (EHCU)
C0266
(66) Fail Safe Relay (FSR) Shorted to
Battery



Relay (EHCU)
C0267
(67) ABS Motor Shorted to Ground



Motor (EHCU)
C0268
(68) ABS Motor Shorted to Battery



Motor (EHCU)
C0271
(71) ECU Failure or Valve +B Circuit Open



EHCU
C0274
(74) ABS Operation Long Time



EHCU

C0276
(76) G-Sensor Malfunction



Sensor or Wiring




Battery, Wiring or EHCU
(less than 9V) C0277
(77) Power Supply Low Input




Battery or Wiring
(less than 10V)
C0278
(78) Power Supply High Input



Battery or Wiring EHCU
C0282
(82) 4 Wheel Drive State Input Signal Failure



Wiring
C0285
(85) Assembly Error (G-sensor)



Vehicle (Sensor or EHCU)

*A : When three or more failure are detected, or when
failure containing both front wheels and each rear
wheels are detected, EBD warning lamp is "ON"
and control is canceled.
*B : ABS lamp is “OFF” when the ABS lamp is “ON”
after a repair until vehicles speed becomes more
than 6km/h (4mph) in the following ignition cycle
and failure is not detected.

BRAKE CONTROL SYSTEM 5A-33

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 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

















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 pedaled).
B05RW0005

5A-34 BRAKE CONTROL SYSTEM

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 on small
order.

C05L300017
The DTC 12 is displayed repeatedly.

5A-38 BRAKE CONTROL SYSTEM

Wheel Speed Sensor Inspection Procedure
Procedure
1.Ignition "OFF".
2.Disconnect the each wheel speed sensors.
3.Check the voltage at sensor harness connector.
Note : Voltage measurement is performed in the phase
where the wheel speed sensor is installed in vehicles.

C05L300019
Connector Pin-outs

Front Wheel Speed Sensor
1 (+) (+12V)
2 (-) (signal)

Rear Wheel Speed Sensor
1 LH (+) (+12V)
2 LH (-) (signal)
3 RH (+)(+12V)
4 RH (-) (signal)






Output Value
High State 1.28~2.2V
Low State 0.5~0.86V
High-Low
Difference more than 0.8V

BRAKE CONTROL SYSTEM 5A-39

Symptom Diagnosis
The symptoms that cannot be indicated by warning
lamp 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 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 8 Go to Step 5
5 Is the each wheel speed sensor output normal?
- Go to Step 6 Replace
wheel speed
sensor or
repair
harness.
Go to Step 7
6 Is the 4WD control system function normal?
- 2-4WD Repair
or Go to Step
7 Repair or
replace 2-
4WD control
System.
Go to Step 7
7 Reconnect all components, ensure all components
are properly mounted.
Was this step finished?
- Repeat the
“Basic
diagnostic
flow chart” Go to Step 7

5A-40 BRAKE CONTROL SYSTEM

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 each sensor output normal?
- 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; 2WD Model or 4WD 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.
Was 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 each sensor output normal?
- Go to Step 4 Replace
sensor or
repair
harness.
Go to Step 6
4 Is 2-4WD system function normal?
- Go to Step 5 Replace 2-
4WD controll
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; 2WD Model or 4WD Model) - Replace
EHCU.
Go to Step 6 Repair.
Go to Step 6
6 Reconnect all components, ensure all components
are properly mounted.
Was this step finished?
- Repeat the
“Basic
diagnostic
flow chart” Go to Step 6

5A-42 BRAKE CONTROL SYSTEM

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 under 10 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
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 one condition 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; 2WD or 4WD 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.
Was this step finished?
- Repeat the
“Basic
diagnostic
flow chart” Go to Step 7

5A-44 BRAKE CONTROL SYSTEM

DTC C0221 (Flash Code 21) Front Right Wheel Speed Sensor Short Circuit or
Circuit Open

LTW35AMF000101

Step Action
Value(s) Yes No
1 Was 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.
Was 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.
Was a problem found?
- Verify repair Go to Step 4

BRAKE CONTROL SYSTEM 5A-45

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
Tech2.
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 ; 2WD model or 4WD model)
Was the action complete? - Verify repair -