Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 163

 

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Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 163

 

 

5A–30

BRAKE CONTROL SYSTEM

Symptom Diagnosis

The symptoms that cannot be indicated by warning light
can be divided in the following five categories:

1. ABS works frequently but vehicle does not

decelerate.

2. Uneven braking occurs while ABS works.
3. The wheels lock during braking.
4. Brake pedal feel is abnormal.
5. Braking sound (from EHCU) is heard while not

braking.

These are all attributed to problems which cannot be
detected by EHCU self-diagnosis.  Use the customer
complaint and test to determine which symptom is
present.  Then follow the appropriate flow chart listed
below.

No

Symptom

Diagnostic Flow Charts

No.

Sym tom

Without TECH 2

With TECH 2

1

ABS works frequently but vehicle does not decelerate.

Chart A-1

Chart TA-1

2

Uneven braking occurs while ABS works.

Chart A-2

Chart TA-2

3

The wheels are locked.

Chart A-3

Chart TA-3

4

Brake pedal feel is abnormal.

Chart A-4

—

5

Braking sound (from EHCU) is heard while not braking. 

Chart A-5

Chart TA-5

Chart A-1 ABS Works Frequently But Vehicle Does Not Decelerate

Step

Action

Yes

No

1

Is braking force distribution normal between front and rear of
vehicle?

Go to 

Step 2

Repair brake

parts.

Go to 

Step 7

2

Are axle parts installed normally?

Go to 

Step 3

Repair axle parts.

Go to 

Step 7

3

Is there play in each or any wheel speed sensor?

Repair wheel

speed sensor.

Go to 

Step 7

Go to 

Step 4

4

Is there damage, or powdered iron sticking to each or any wheel
speed sensor/sensor ring?

Replace or repair

sensor or sensor

ring.

Go to 

Step 7

Go to 

Step 5

5

Is the output of each wheel speed sensor normal? (Refer to 

Chart

C-1 or TC-1)

Go to 

Step 6

Replace wheel

speed sensor or

repair harness.

Go to 

Step 7

6

Is the input of TOD control unit normal?

Go to 

Step 7

Replace TOD
control unit or

repair harness.

Go to 

Step 7

7

Reconnect all components, ensure all components are properly
mounted.

Was this step finished?

Repeat the “Basic

diagnostic flow

chart”

Go to 

Step 7

5A–31

BRAKE CONTROL SYSTEM

Chart TA-1 ABS Works Frequently But Vehicle Does Not Decelerate (Use TECH 2)

Step

Action

Yes

No

1

1. Connect TECH 2.
2. Make sure of the output conditions of each sensor.

Is the output of each sensor normal?

Go to 

Step 2

Replace wheel

speed sensor.

Go to 

Step 3

2

Return to Chart A-1.

Was the Chart A-1 finished?

Go to 

Step 3

Go to 

Step 2

3

Reconnect all components, ensure all components are properly
mounted.

Was this step finished?

Repeat the “Basic

diagnostic flow

chart”

Go to 

Step 3

Chart A-2 Uneven Braking Occurs While ABS Works

Step

Action

Yes

No

1

Is there play in each or any sensor?

Repair.

Go to 

Step 5

Go to 

Step 2

2

Damage or powdered iron sticking to each or any sensor/sensor
ring?

Repair.

Go to 

Step 5

Go to 

Step 3

3

Is the output of each sensor normal? (Refer to 

Chart C-1 or TC-1)

Go to 

Step 4

Replace sensor

or repair harness.

Go to 

Step 5

4

Is brake pipe connecting order correct?

Replace H/U.

Go to 

Step 5

Reconnect brake

pipe correctly.

Go to 

Step 5

5

Reconnect all components, ensure all components are properly
mounted.

Was this step finished?

Repeat the “Basic

diagnostic flow

chart”

Go to 

Step 5

Chart TA-2 Uneven Braking Occurs While ABS Works (Use TECH 2)

Step

Action

Yes

No

1

1. Connect TECH 2.
2. Make sure of the output conditions of each sensor.

Is the output of each sensor normal?

Go to 

Step 2

Go to 

Step 3

2

Check piping by TECH 2 ACTUATOR TEST

Is the piping normal?

Replace EHCU.

Go to 

Step 4

Repair the pipe.

Go to 

Step 4

3

Repair and check the wheel speed sensor (Refer to 

Chart B-20 to

B-23 , C-1 or TC-1).

Was the each chart finished?

Go to 

Step 4

Go to 

Step 3

4

Reconnect all components, ensure all components are properly
mounted.

Was this step finished?

Repeat the “Basic

diagnostic flow

chart”

Go to 

Step 4

5A–32

BRAKE CONTROL SYSTEM

Chart A-3, TA-3  The Wheels Are Locked

Step

Action

Yes

No

1

Is ABS working?

Go to 

Step 2

Go to 

Step 4

2

Is vehicle speed under 10 km/h (6mph)?

Go to 

Step 3

Normal.

3

Is sensor output normal? (Chart C-1 or TC-1)

Go to 

Step 4

Replace sensor

or repair harness.

Go to 

Step 6

4

Is front TOD control unit normal?

Go to 

Step 5

Replace TOD
control unit or

repair harness.

Go to 

Step 6

5

Is hydraulic unit grounded properly?

Replace EHCU.

Go to 

Step 6

Repair.

Go to 

Step 6

6

Reconnect all components, ensure all components are properly
mounted.

Was this step finished?

Repeat the “Basic

diagnostic flow

chart”

Go to 

Step 6

Chart A-4 Brake Pedal Feed Is Abnormal

Step

Action

Yes

No

1

Is the stop light actuated when the brake pedal is depressed?

Go to 

Step 2

Go to 

Step 3

2

1. Turn the ignition switch off.
2. Disconnected EHCU connector.

Is the check voltage EHCU connector terminals 13 to 7 when
brake pedal is depressed than battery voltage?

Go to 

Step 4

Harness NG

between brake

SW and EHCU.

Go to 

Step 6

3

Is stop light fuse normal?

Go to 

Step 5

Replace stop light

fuse.

Go to 

Step 6

4

Is the check continuity between EHCU connector terminals, 7 to
body grounded?

Go to 

Step 6

Repair body

grounded

harness.

Go to 

Step 6

5

Is brake SW normal?

Repair stop light

harness.

Go to 

Step 6

Replace brake

SW.

Go to 

Step 6

6

Reconnect all components, ensure all components are properly
mounted.

Was this step finished?

Repeat the “Basic

diagnostic flow

chart”

Go to 

Step 6

5A–33

BRAKE CONTROL SYSTEM

Chart A-5, TA-5 Braking Sound (From EHCU) Is Heard While Not Braking

Step

Action

Yes

No

1

Is this the first vehicle start after engine start?

Normal.

(It is self

checking sound.)

Go to 

Step 2

2

Is vehicle speed under 10 km/h (6 mph)?

Normal.

(It is self

checking sound.)

Go to 

Step 3

3

Check for the following condition:

D

At the time of shift down or clutch operation.

D

At the time of low road friction drive (ice or snow road) or rough
road drive.

D

At the time of high-speed turn.

D

At the time of passing curb.

D

At the time of operating electrical equipment switches.

D

At the time of racing the engine (over 5000 rpm).

Did it occur under any one condition above?

ABS may

sometimes be

actuated even

when brake pedal

is not applied.

Go to 

Step 4

4

Is there play in each or any sensor/wheel speed sensor rings?

Repair.

Go to 

Step 7

Go to 

Step 5

5

Damage or powdered iron sticking to each or any sensor/wheel
speed sensor ring?

Repair.

Go to 

Step 7

Go to 

Step 6

6

Is each sensor output normal? (Refer to 

Chart C-1 or TC-1).

Check harness/

connector for

suspected

disconnection

If no

disconnection is

found, replace

Coil integrated

module.

Go to 

Step 7

Repair.

Go to 

Step 7

7

Reconnect all components, ensure all components are properly
mounted.

Was this step finished?

Repeat the “Basic

diagnostic flow

chart”

Go to 

Step 7

 

 

 

 

 

 

 

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