Isuzu KB P190. Manual - part 169

BRAKE CONTROL SYSTEM   5A-83 

Step Action  Value(s) Yes 

No 

5  

1. 

Ignition 

"OFF". 

  2. Connect 2-4WD control unit. 

 3. Disconnect EHCU. 

  4. Ignition "ON," engine "OFF." 

  5. Install the high impedance digital multimeter. 

  6. Check the transfer (2-4WD control unit) signal 

value. (Battery voltage is more than 10V.) 

Was the value normal? 

Transfer 2WD 

Mode: 8.3Hz 

(±15%) 

Transfer 4WD 

Mode: 4.2Hz 

(±15%) 

Go to Step 7 

Go to Step 6 

6 

Replace 2-4WD control unit. 

Is the action complete? 

- 

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 
Tech 2. 

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) 

Is the action complete? 

- 

Verify repair 

- 

 

5A-84   BRAKE CONTROL SYSTEM 

DTC C0285 (Flash Code 85) Control Module Vehicle Options Incorrect 

 

 

 

 

 

RTW75AMF001501 

 

Step Action  Value(s) 

Yes 

No 

1 

Were the steps of the “Basic Diagnostic Flow Chart” 
performed? 

- 

Go to Step 2 

Go to Basic 

Diagnostic 

Flow Chart 

2  

1. 

Ignition 

“OFF”. 

  2. Check for vehicle type and EHCU type. 

    (Vehicle type : 2WD or 4WD) 

  3. Check that the EHCU type is the same as the 

vehicle type. 

    If the EHCU type differs from the vehicle type, 

EHCU is replaced. 

Note: Check the EHCU type for specification, when 
the EHCU is replaced. 
(Specification ; 2WD model or 4WD model) 

Is the action complete? 

- 

Go to Step 3 

- 

3 

  1. Check for vehicle type. (Vehicle type : 2WD or 

4WD) 

Is vehicle type 2WD? 

- 

Go to Step 4 

Go to Step 5 

BRAKE CONTROL SYSTEM   5A-85 

Step Action  Value(s) 

Yes 

No 

4  

1. 

Ignition 

"OFF". 

  2. Check for a poor condition at the EHCU harness 

connector. 

  3. 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. 

  4. If a problem is found, repair as necessary. 

Was a problem found? 

- 

Verify repair 

Go to Step 9 

5 

  1. Ignition "OFF", disconnect the EHCU and G sensor.

  2. Check the circuit between EHCU and G sensor. 

(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 6 

Go to Step 6 

6 

  1. Remove the G sensor. 

  2. Reconnect G sensor and EHCU 

  3. Install the Tech 2. 

  4. Ignition "ON", engine "OFF".  

  5. Observe the G sensor reading on Tech 2.  

If G sensor inclines, reading voltage will change. 

Is the reading voltage between specified values? 

1.0 – 4.0 V 

Go to Step 7 

Go to Step 8 

7  

1. 

Ignition 

"OFF". 

  2. Install the G sensor. 

  3. Install the Tech 2. 

 

  4. Ignition "ON", engine "OFF".  

  5. Select "Display DTCs" with the Tech 2. 

Are any DTCs stored? 

- 

Go to Step 8 

Verify repair 

8 

  1. Replace G 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 
Tech 2. 

Are any DTCs stored? 

- 

Go to Step 9 

Verify repair 

9 Replace 

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 

- 

 
 

5A-86   BRAKE CONTROL SYSTEM 

Special Tools 

 

ILLUSTRATION 

TOOL NO. 

TOOL NAME 

 

5–8840–0366–0 

High impedance 

multimeter 

 

5–8840–2835–0 

Connector Test Adapter

Kit (With Test Lamp) 

 

Tech2 Kit