change wheel OPEL FRONTERA 1998 Owner's Manual

5A–4
BRAKE CONTROL SYSTEM
normal braking when a malfunction has occurred in the
ABS.
The EHCU has a self-diagnosing function which can
indicate faulty circuits during diagnosis.
The EHCU is mounted on the engine compartment front
right side. It consists of a Motor, Plunger Pump, Solenoid
Valves and Check Valve.
On the outside, the relay box containing a motor relay and
a valve relay is installed.
Solenoid Valves: Reduces or holds the caliper fluid
pressure for each front disc brake or both rear disc brakes
according to the signal sent from the EHCU.
Reservoir: Temporarily holds the brake fluid that returns
from the front and rear disc brake caliper so that pressure
of front disc brake caliper can be reduced smoothly.
Plunger Pump: Feeds the brake fluid held in the reservoir
to the master cylinder.
Motor: Drives the pump according to the signal from
EHCU.
Check Valve: Controls the brake fluid flow.
ABS Warning Light
821RW033Vehicles equipped with the Anti-lock Brake System have
an amber “ABS” warning light in the instrument panel.
The “ABS” warning light will illuminate if a malfunction in
the Anti-lock Brake System is detected by the Electronic
Hydraulic Control Unit (EHCU). In case of an electronic
malfunction, the EHCU will turn “ON” the “ABS” warning
light and disable the Anti-lock braking function.
The “ABS” light will turn “ON” for approximately three
seconds after the ignition switch is to the “ON” position.
If the “ABS” light stays “ON” after the ignition switch is the
“ON” position, or comes “ON” and stays “ON” while
driving, the Anti-lock Brake System should be inspected
for a malfunction according to the diagnosis procedure.
Wheel Speed Sensor
It consists of a sensor and a rotor. The sensor is attached
to the knuckle on the front wheels and to the axle shaft
bearing holder on the rear wheels.
The rotor is press-fit in the axle shaft.The flux generated from electrodes magnetized by a
magnet in the sensor varies due to rotation of the rotor,
and the electromagnetic induction generates alternating
voltage in the coil. This voltage draws a “sine curve” with
the frequency proportional to rotor speed and it allows
detection of wheel speed.
G-Sensor
The G-sensor installed inside the center console detects
the vehicle deceleration speed and sends a signal to the
EHCU. In 4WD operation, all four wheels may be
decelerated in almost the same phase, since all wheels
are connected mechanically.
This tendency is noticeable particularly on roads with low
friction coefficient, and the ABS control is adversely
affected.
The G-sensor judges whether the friction coefficient of
road surface is low or high, and changes the EHCU’s
operating system to ensure ABS control.
Normal and Anti-lock Braking
Under normal driving conditions, the Anti-lock Brake
System functions the same as a standard power assisted
brake system. However, with the detection of wheel
lock-up, a slight bump or kick-back will be felt in the brake
pedal. This pedal “bump” will be followed by a series of
short pedal pulsations which occurs in rapid succession.
The brake pedal pulsation will continue until there is no
longer a need for the anti-lock function or until the vehicle
is stopped. A slight ticking or popping noise may be heard
during brake applications when the Anti-lock features is
being used.
When the Anti-lock feature is being used, the brake pedal
may rise even as the brakes are being applied. This is
also normal. Maintaining a constant force on the pedal
will provide the shortest stopping distance.
Brake Pedal Travel
Vehicles equipped with the Anti-lock Brake System may
be stopped by applying normal force to the brake pedal.
Although there is no need to push the pedal beyond the
point where it stops or holds the vehicle, by applying more
force the pedal will continue to travel toward the floor.
This extra brake pedal travel is normal.
Acronyms and Abbreviations
Several acronyms and abbreviations are commonly used
throughout this section:
ABS
Anti-lock Brake System
CKT
Circuit
DLC
Data Link Connector
EHCU
Electronic Hydraulic Control Unit
FL
Front Left

5A–11 BRAKE CONTROL SYSTEM
Data List
DisplayContentOK/NG Criteria for Data
Battery VoltageVo l t a g eBetween 10-16.9V
Brake Light SwitchOpen/CloseOpen(0V) when pedal is released
Closed(12V) when pedal is depressed.
Front Left Wheel Speed
Front Right Wheel Speed
Rear Left Wheel Speed
Rear Right Wheel SpeedMPH(km/h)Start the vehicle and make sure of linear change in each
wheel speed.
Turn each wheel by hand and make sure that each
speed data change.
Wheel Sensor StatusOK/NGTo be OK usually
G-sensorLow/HighTo be Low usually
Transfer Monitor(TOD)2 Wheel Drive
4 Wheel DriveWhen 2WD: 2 Wheel Drive
When 4WD: 4 Wheel Drive
Off-Road Switch
(Transmission Input)
Active/InactiveWhen shift lever position is 1, 2 and R: Active (M/T)
(Transmission Input)When shift lever position is L and R: Active (A/T)
Valve RelayActive/InactiveTo be Active usually
ABS StateON/OFFTo be OFF usually
ABS RelayActive/InactiveTo be Active usually
Return Pump RelayActive/InactiveTo be Inactive usually
Front Left Isolation ValveActive/InactiveTo be Inactive usually
Front Left Dump Valve
Front Right Isolation Valve
Front Right Dump Valve
Rear Isolation Valve
Rear Dump Valve
ABS Warning LampON/OFFTo be ON usually (while engine stopped)

5A–56
BRAKE CONTROL SYSTEM
Chart B-24 Sensor Signal Input Abnormality (DTC 65)
StepActionYe sNo
1Using TECH 2?Go to Step 2Go to Step 3
21. Connect TECH 2.
2. Select Snap shot manual trigger.
3. With wheel speed data displayed, run the vehicle when speed
has arrived at 30 km/h (18 mph).
4. Check speed data on each wheel (refer to the criterion given
below). *1
Is the abnormal sensor condition found?
Replace.
Go to Step 8
Go to Step 3
All the sensors
should follow the
following
flowchart (without
using TECH 2).
3Is there play in sensor/sensor ring?Repair.
Go to Step 8
Go to Step 4
4Is there powdered iron sticking to sensor/sensor ring?Repair.
Go to Step 8
Go to Step 5
5Is there a broken tooth or indentation in sensor ring?Replace sensor
ring.
Go to Step 8
Go to Step 6
6Is there play in wheel bearing?Adjust or repair.
Go to Step 8
Go to Step 7
7Is the check wiring between sensor and EHCU normal?
Replace EHCU.
Go to Step 8
Repair, and
perform system
self-check.
Go to Step 8
81. Reconnect all components, ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat “Basic
diagnostic flow
chart.”
Go to Step 8
Sensor Signal Abnormality Criteria using
TECH 2
1. While driving, the speed of one or two wheels 25% or
more higher than that of the other wheels.
2. The speed of one or two wheels is 10 km/h (6 mph) or
more higher than that of the other wheels.
3. During steady driving, wheel speed changes abruptly.
*1 The vehicle must run on a level paved road.
NOTE: Even after repairing the faulty part the warning
light (W/L) does not go out if the vehicle is at a stop.
Turn the ignition switch to the ON position and drive the
vehicle at 12 km/h or higher to make sure that the warning
light goes out.
It is important to verify that the correct tires are installed
on vehicle.

6E–94
ENGINE DRIVEABILITY AND EMISSIONS
Idle Air Control (IAC) System Check
StepActionVa l u e ( s )Ye sNo
11. Ignition “OFF.”
2. Connect the Tech 2.
3. Set the parking brake.
4. Block the wheels.
5. Turn the air conditioning “OFF.”
6. Idle the engine in Park (A/T) or Neutral (M/T).
7. Operate the IAC test.
8. The engine speed should decrease and increase as
the IAC is cycled.
Does the RPM change?
—Go to Step 2Go to Step 3
2RPM should change smoothly.
Does the RPM change within the range specified?700-1500
RPM
—Go to Step 3
3Check the IAC passages.
Are the IAC passages OK?
—Go to Step 4Go to Step 5
4Clear any obstruction from the IAC passages.
Is the action complete?
—Verify repair—
5Replace the IAC. Refer to On-Vehicle Service, Idle Air
Control Valve.
Is the action complete?—Verify repair—

AUTOMATIC TRANSMISSION (AW30-40LE) 7A–45
• Changes solenoid output pattern as following figure
The shift theory at shift solenoid failure
At failure decision
Executes following items in addition to above control
items at failure detection.
•Turns Solenoid power supply OFF
•Blinks "CHECK TRANS" lamp
•Stores the failure information in failure-memory
*Prohibits failure detection of S1, S2, SL, STH,
Selector position switch, and Oil temp. sensor.
Conditions of turning "CHECK TRANS" off:
Turns "CHECK TRANS" lamp off after ignition is turned
ON
OFF ON.
Reversion conditions from fail-safe:
At failure detection
When a normal judgment is obtained by rechecking
during shifting.
At failure decision
Recovers at the same time as the conditions of
turning “CHECK TRANS” lamp off are satisfied.
Test description:
The following numbers correspond to circled numbers on
the diagnostic char t.
(1) With the key "ON", the voltage between the TCM
terminals (C78-4) and (C78-15 or 19) is 8 to 16V.
(2) When the driving wheels revolve with the 3rd speed
gear, the voltage is 1 V or less.
(3) The solenoid resistance is within the range of 11 to
15
.
Diagnostic aids:
In case of faulty connection, open or shor ted circuit to
the TCM terminal (C78-4), DTC P0753 is displayed. A
intermittent failure may be caused by a poor connection,
rubbed through wire insulation or a wire broke inside the
insulation.Shift
lever
Po s i t i o nNormal S1 failure S2 filure S1 and S2 failure
Gear S1 S2 Gear S1 S2 Gear S1 S2 Gear S1 S2
D1
3
1
O/D 2O/D3
O/DO/D
213
1
3 2O/D3
L1313
2O/D

7A–48 AUTOMATIC TRANSMISSION (AW30-40LE)
DTC P0758 (FLASHING CODE 32) SOLENOID 2 FAILURE (S2)
D07RY00047Circuit description:
The solenoid S2 changes the hydraulic route with the
signals from the TCM according to the vehicle speed and
the throttle opening to control shifting. When the solenoid
S1 or S2 fails, the hydraulic circuit is mechanically
operated as a backup.
Fail-safe control:
The TCM controls fail-safe by detecting S1, S2 shift
solenoid failure.
Failure detection:
GND SHORT detection
• When SHORT detection continues for 0.3 sec.
• When SHORT failure detection continues 8 times.
Open detection
• When OPEN detection continues for 0.5 sec.
• When OPEN failure detection continues 8 times.
Contents of control:
At failure detection
• Lock-up control inhibit
• Up hill and down hill control inhibit
• Squat control inhibit
• Changes solenoid output pattern as "The shift theory
at shift solenoid failure". (See DTC P0753)
At failure decision
Executes following items in addition to above control
items at failure detection.
• Turns Solenoid power supply OFF
• Blinks "CHECK TRANS" lamp
• Stores the failure information in failure-memory
*Prohibits failure detection of S1, S2, SL, STH,Selector position switch, and Oil temperature sensor.
Conditions of turning "CHECK TRANS" off:
Turns "CHECK TRANS" lamp off after ignition is turned
ON
OFF ON.
Reversion conditions from fail-safe:
At failure detection
When a normal judgment is obtained by rechecking
during shifting.
At failure decision
Recovers at the same time as the conditions of
turning “CHECK TRANS” lamp off are satisfied.
Test description:
The following numbers correspond to circled numbers on
the diagnostic char t.
1 With the key "ON", the voltage between the TCM
terminals (C78-3) or (C78-15 or 19) is 1V or less.
2 When the driving wheels revolve with the 2nd
speed gear, the voltage is 8 to 16V.
3 The resistance of the solenoid is in the range of
11 to 15
.
Diagnostic aids:
In case of faulty connection, open or shor ted circuit to the
TCM terminal (C78-3), DTC P0758 is displayed. A
intermittent failure may be caused by a poor connection,
rubbed through wire insulation or a wire broken inside
the insulation.