Isuzu KB P190. Service manual — part 156

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 repair

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.

5A-32 BRAKE CONTROL SYSTEM

Data List (Tech 2)

The data displayed by DATA LIST are as follows:

Strings Units

Description

FL Wheel Speed (Front Left)

Km/h (MPH)

FR Wheel Speed (Front Right)

Km/h (MPH)

RL Wheel Speed (Rear Left)

Km/h (MPH)

RR Wheel 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 Wheel Drive Status

2 Wheel Drive/
4 Wheel Drive

ABS Warning lamp

On/Off

To be “Off” usually

EBD Warning 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

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 Wheel Speed Sensor
Short Circuit or Circuit Open

×*A

×

Sensor or Wiring

C0222

(22)

Front Right Wheel Speed Sensor
Signal Malfunction

*B

×*A

×

Sensor 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 Signal
Malfunction

*B

×*A

×

Sensor 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
Signal Malfunction

*B

×*A

×

Sensor 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 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 Wiring

5A-34 BRAKE CONTROL SYSTEM

Warning Lamp

System Control

Main Items

DTC

(Flash

Code)

Description

ABS

Brake

(EBD)

ABS EBD

×

×

Battery, Wiring or EHCU

(less than 8V)

C0277

(77)

System Voltage Low

×

×

Battery or Wiring

(less than 10V)

C0278

(78)

System Voltage High

×

×

Battery or Wiring EHCU

C0282

(82)

4 Wheel Drive State Input Signal
Failure

×

×

Wiring

C0285

(85)

Control Module Vehicle Options
Incorrect

×

×

Vehicle (Sensor or EHCU)

*A : When 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.