Opel Frontera UBS. Manual - part 206

5A–37

BRAKE CONTROL SYSTEM

Step

No

Yes

Action

5

Is front 4WD controller normal?

Replace EHCU.

Go to Step 9

Replace 4WD

controller or

repair harness.

Go to Step 9

6

Is transmission input normal? (Chart C-2 or TC-2)

Go to Step 7

Replace SW or

repair harness

Go to Step 9

7

Is front 4WD controller normal?

Go to Step 8

Replace 4WD

controller or

repair harness.

Go to Step 9

8

Is hydraulic unit grounded properly?

Replace EHCU.

Go to Step 9

Correct.

Go to Step 9

9

Reconnect all components, ensure all components are properly
mounted.

Was this step finished?

Repeat the “Basic

diagnostic flow

chart.”

Go to Step 9

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.
3. Measure voltage between the EHCU connector terminal 10

and 15 when brake pedal is depressed.

Is the voltage equal to the battery voltage?

Go to Step 4

Harness NG

between brake

SW and EHCU.

Go to Step 7

3

Is stop light fuse C-14 normal?

Go to Step 5

Replace fuse

C-14.

Go to Step 7

4

Is there continuity between EHCU connector terminals, 12 and 15
to body ground?

Go to Step 6

Repair body

grounded

harness.

Go to Step 7

5

Is the brake SW normal?

Repair stop light

harness.

Go to Step 7

Replace brake

SW.

Go to Step 7

6

Is the check harness/connector for suspended disconnection?

Hydraulic system

leakage or air

entry (Refer to

servicing

“Leakage or

brake fluid” )

Go to Step 7

Repair harness.

Go to Step 7

7

Reconnect all components and ensure all components are
properly mounted.

Was this step finished?

Repeat the “Basic

diagnostic flow

chart.”

Go to Step 7

5A–38

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 time the vehicle is being driven after starting the
engine?

It is self checking

sound.

Normal.

Go to Step 2

2

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

It is self checking

sound.

Normal.

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 

m

 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

sometime be

actuated even

when brake pedal

is not applied.

Go to Step 4

4

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

Go to Step 5

Repair.

Go to Step 7

5

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

Go to Step 6

Repair.

Go to Step 7

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

EHCU.

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

5A–39

BRAKE CONTROL SYSTEM

Diagnostic Trouble Codes

Choose and trace an appropriate flowchart by the
numbers listed below to find fault and repair.

Code

Item

Diagnosis

Chart No.

12

Start Code

Normal

—

14

EHCU Function

Abnormality in input/output, operational and
control circuits

B-2

15

Power Voltage Drop

B-3

16

CLASS–2 Communication Line Ab-
normality

B-4

21

G-sensor

Wiring disconnection

B-5

23

Transmission Input

Input abnormality

B-6

24

Transfer Monitor

B-7

32

Motor & Motor Relay

Shorted or disconnected coil

B-8

35

Valve Relay

Shorted or disconnected coil/wiring

B-9

41

FL Holding Solenoid Valve

Shorted or disconnected coil/wiring

B-10

42

FL Decompression Solenoid Valve

Shorted or disconnected coil/wiring

B-11

43

FR Holding Solenoid Valve

Shorted or disconnected coil/wiring

B-12

44

FR Decompression Solenoid Valve

Shorted or disconnected coil/wiring

B-13

45

Rear Holding Solenoid Valve

Shorted or disconnected coil/wiring

B-14

46

Rear Decompression Solenoid Valve

Shorted or disconnected coil/wiring

B-15

51

FL Wheel Speed Sensor

Disconnected coil/wiring

B-16

52

FR Wheel Speed Sensor

Disconnected coil/wiring

B-17

53

RL Wheel Speed Sensor

Disconnected coil/wiring

B-18

54

RR Wheel Speed Sensor

Disconnected coil/wiring

B-19

61

FL Wheel Speed Sensor

Shorted coil/wiring

B-20

62

FR Wheel Speed Sensor

Shorted coil/wiring

B-21

63

RL Wheel Speed Sensor

Shorted coil/wiring

B-22

64

RR Wheel Speed Sensor

Shorted coil/wiring

B-23

65

Sensor Signal Input

Wrong number of teeth

B-24

5A–40

BRAKE CONTROL SYSTEM

Diagnosis By “ABS” Warning Light
Illumination Pattern

In the event that there is abnormality in the “ABS” warning
light illumination pattern while the key is in the ON position
or if the warning light is actuated during driving, trouble
should be diagnosed on a illumination pattern basis as
follows:

No.

Condition

“ABS” Warning Light Illumination Pattern

Diagnostic

1

Warning light is actu-
ated normally

Normal

2

Warning light is not lit

Warning light lighting circuit
trouble

→

Go to Chart B-1

3

Warning light remains
ON

Diagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.

4

Warning light is actu-
ated while driving

Diagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.

Diagnostic Trouble Codes (DTCs)

When the warning light in the meter remains ON, the
EHCU stores the fault identification and disables the
ABS.

1. How to display and erase DTCs:

NOTE:

D

If DTCs are not displayed, harness C-4 connector
terminal 30 and I-10 connector terminal 2 may be
disconnected.  Repair the harness and try DTC
display again.

D

DTCs can be displayed also by TECH 2.  Select mode
“F0: Diagnostic Trouble Codes” from Application
Menu.

1. How to start DTC display:

D

Confirm that the vehicle has come to a complete
stop (with the wheels standing still) and that the
brake pedal is not depressed.  (Unless these two
conditions are satisfied, DTC display cannot be
started.)

D

With IGN OFF, connect #12 terminal with #4
terminal or # 5 terminal (GND) . Then turn IGN ON.