2004 ISUZU TF SERIES ignition

BRAKE CONTROL SYSTEM 5A-73

DTC C0251 (Flash Code 51) Rear Isolation Solenoid Circuit Open or Shorted
to Ground
DTC C0252 (Flash Code 52) Rear Dump Solenoid Circuit Open or Shorted to
Ground
DTC C0253 (Flash Code 53) Rear Isolation Solenoid Circuit Shorted to Battery
DTC C0254 (Flash Code 54) Rear Dump Solenoid Circuit Shorted to Battery



RTW45AMF000201

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. Ignition “OFF”.
2. 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 or short to
voltage.
3. If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 3

5A-74 BRAKE CONTROL SYSTEM

Step Action
Value(s) Yes No
3 1. Ignition “ON,” engine “OFF.”
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 4 Verify repair
4 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 -

BRAKE CONTROL SYSTEM 5A-75

DTC C0265 (Flash Code 65) Fail Safe Relay (FSR) Shorted to Ground
DTC C0266 (Flash Code 66) Fail Safe Relay (FSR) Shorted to Battery



RTW45AMF000201

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. Ignition “OFF”.
2. 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 or short to
voltage.
3. If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 3
3 1. Ignition “ON,” engine “OFF.”
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 4 Verify repair

BRAKE CONTROL SYSTEM 5A-77

DTC C0267 (Flash Code 67) ABS Motor Shorted to Ground
DTC C0268 (Flash Code 68) ABS Motor Shorted to Battery



RTW45AMF000201

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. Ignition “OFF”.
2. 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 or short to
voltage.
3. If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 3
3 1. Ignition “ON,” engine “OFF.”
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 4 Verify repair

BRAKE CONTROL SYSTEM 5A-79

DTC C0271 (Flash Code 71) ECU Failure or Valve +B Circuit Open



RTW45AMF000201

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. Ignition “OFF”.
2. 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 or short to
voltage.
3. If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 3
3 1. Ignition “ON,” engine “OFF.”
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 4 Verify repair
4 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 -

5A-80 BRAKE CONTROL SYSTEM

DTC C0274 (Flash Code 74) ABS Operation Long Time


RTW45AMF000201

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 Was the “Basic Inspection Procedure” performed?
- Go to Step 3 Go to Basic
Inspection
Procedure
3 1. Check for a poor connection at the wheel speed
sensor harness connector.
2. Check installation condition for wheel speed
sensor.
3. If a problem is found, repair as necessary.
Was a problem found? - Verify repair Go to Step 4
4 1. Check condition for sensor rotor.
2. If a problem is found, repair as necessary.
Was a problem found? - Verify repair Go to Step 5
5 1. Ignition “OFF,” disconnect the EHCU and wheel
speed sensor.
2. Check the circuit between EHCU and wheel speed
sensor.(short ground, or short to voltage.)
3. If a problem is found, repair as necessary.
Was a problem found? - Verify repair Go to Step 6

BRAKE CONTROL SYSTEM 5A-81

Step Action
Value(s) Yes No
6 1. Ignition “OFF”.
2. 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 or short to
voltage.
3. If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 7
7 1. Ignition “ON,” engine “OFF.”
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 8 Verify repair
8 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 -

5A-82 BRAKE CONTROL SYSTEM

DTC C0276 (Flash Code 76) G-Sensor Malfunction


RTW35AMF000301

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 G-sensor
harness connector.
2. If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 3
3 1. Ignition “OFF”, disconnect the G-sensor and
EHCU.
2. Ignition “ON”, engine “OFF”.
3. Check the supply voltage to G-sensor.
Was the value normal? Battery
Voltage Go to Step 5 Go to Step 4
4 Repair or replace the power supply circuit.
Was the action complete? - Verify repair -
5 1. Check the circuit between EHCU and G-sensor.
(Circuit for an open, short to ground, or short to
voltage.)
2. If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 6