Isuzu KB P190. 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.