2004 ISUZU TF SERIES brake

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.

5A-32 BRAKE CONTROL SYSTEM

Diagnosis By “ABS” Warning Lamp
Illumination Pattern
In the event that there is abnormality in the “ABS”
warning Lamp illumination pattern while the key is in the
ON position or if the warning Lamp is actuated during
driving, trouble should be diagnosed on a illumination
pattern basis as follows:

No. Condition “ABS” Warning Lamp Illumination Pattern Diagnostic
1 Warning Lamp is
actuated normally
Normal
2 Warning Lamp is not
lit
Warning Lamp lighting circuit
trouble. Go to No ABS
Warning Lamp.
3 Warning Lamp
remains ON
Diagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to
the flow charts.
4 Warning 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)
When the warning lamp in the meter remains ON, the
EHCU stores the fault identification and disables the
ABS.

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.

BRAKE CONTROL SYSTEM 5A-35

Basic Diagnostic Flow Chart

RTW45AMF000101

Step Action Value(s) Yes No
1 1. Ignition “ON,”engine “OFF.”
2. Observe the ABS warning lamp.
Note: If a starter switch is turned ON, ABS warning
lamp will turn on and a ABS warning lamp will be
turned 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 Tech2.
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
3 1. Ignition “OFF,” disconnect the EHCU.
2. Check the DLC (Data Link Connector) circuit for an
open, short to ground, or short to voltage.
Also, check the DLC ignition feed circuit for an
open or short to ground and the DLC ground circuit
for an open.
3. If a problem is found, repair as necessary.
Was a problem found?
- Go to Step 2 Go to Step 4

5A-36 BRAKE CONTROL SYSTEM

Step Action Value(s) Yes No
4 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.
Was a problem found?
- Go to Step 2 Go to Step 11
5 Select “Display DTCs” with the Tech 2.
Are any DTCs stored? - Go to Step 6 Go to Step 10
6 Review and record for Tech 2 Failure Records data
and DTCs.
Is the action complete? - Go to Step 7 -
7 Following the DTC is stored.
Is this DTC C0271 stored?
- Go to
applicable
DTC table
after Go to
step 8 Go to Step 8
8 Clear the DTCs by “Clear the Information“ with Tech
2.
Did the DTCs cleared? - Go to Step 9 -
9 Select “Display DTCs” with the Tech 2.
Are any DTCs stored?
- Go to
applicable
DTC table Go to Step 10
10 Review and record for Tech 2 data.
Is the action complete?
- Go to
Symptom
Diagnosis and
Go to Basic
Inspection
Procedure -
11 Replace the EHCU.
Note: Check the EHCU type for specification, when
the EHCU is replaced.
(Specification; 2WD Model or 4WD Model)
Is the action complete? - Verify repair -

BRAKE CONTROL SYSTEM 5A-37

Basic Inspection Procedure
1. Basic Inspection of Service Brake
Step Action
Value(s) Yes No
1 Is the fluid level normal?
- Go to Step 2 Replenish with
fluid
Go to Step 2
2 Does fluid leak?
- Repair
Go to Step 3 Go to Step 3
3 Is the booster function normal?
- Go to Step 4 Repair
Go to Step 4
4 Is the pad and rotor normal?
- Go to Step 5 Repair
Go to Step 5
5 Reconnect all components. Ensure all component
are properly mounted.
Was this step finished? - Finished Go to Step 5

2. Ground Inspection
Step Action
Value(s) Yes No
1 Does ABS related ground points normally?
- Go to Step 2 Repair
Go to Step 2
2 Reconnect all components. Ensure all component
are properly mounted.
Was this step finished? - Finished Go to Step 2