ABS OPEL FRONTERA 1998 Workshop Manual

5A–36
BRAKE CONTROL SYSTEM
StepNo Ye s
Action
10Is the input of 4WD controller normal?
Go to Step 11
Replace
controller or
repair harness.
Go to Step 11
11Reconnect all components and ensure all components are
properly mounted.
Was this step finished?Repeat the “Basic
diagnostic flow
chart.”
Go to Step 11
Chart TA-1 ABS Works Frequently But Vehicle Does Not Decelerate (Use TECH 2)
StepActionYe sNo
11. Connect TECH 2.
2. Make sure of the output conditions of each wheel speed
sensor by mode “F1: Data Display”.
Is the output of each sensor normal?
Go to Step 2
Replace wheel
speed sensor.
Go to Step 3
2Return to Chart A-1.
Was the Chart A-1 finished?
Go to Step 3Go to Step 2
3Reconnect 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
StepActionYe sNo
1Is there play in each sensor?Repair.
Go to Step 5
Go to Step 2
2Is there damage or powdered iron sticking to each sensor/sensor
ring?Repair.
Go to Step 5
Go to Step 3
3Is 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
4Is brake pipe connecting order correct?
Replace EHCU.
Go to Step 5
Reconnect brake
pipe correctly.
Go to Step 5
5Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the “Basic
diagnostic flow
chart.”
Go to Step 5
Chart A-3, TA-3 The Wheels Are Locked
StepActionYe sNo
1Is ABS working?Go to Step 2Go to Step 6
2Is vehicle speed under 10 km/h (6mph)?Normal.Go to Step 3
3Is sensor output normal? (Chart C-1 or TC-1)
Go to Step 4
Replace sensor
or repair harness.
Go to Step 9
4Is transmission input normal? (Chart C-2 or TC-2)
Go to Step 5
Replace SW or
repair harness.
Go to Step 9

5A–38
BRAKE CONTROL SYSTEM
Chart A-5, TA-5 Braking Sound (From EHCU) Is Heard While Not Braking
StepActionYe sNo
1Is this the first time the vehicle is being driven after starting the
engine?It is self checking
sound.
Normal.
Go to Step 2
2Is vehicle speed under 10 km/h (6 mph)?It is self checking
sound.
Normal.
Go to Step 3
3Check for the following condition:
At the time of shift down or clutch operation.
A t t h e t i m e o f l o w drive (ice or snow road) or rough road drive.
At the time of high-speed turn.
At the time of passing curb.
At the time of operating electrical equipment switches.
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
4Is there play in each sensor/wheel speed sensor rings?
Go to Step 5
Repair.
Go to Step 7
5Damage or powdered iron sticking to each sensor/wheel speed
sensor ring?
Go to Step 6
Repair.
Go to Step 7
6Is 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
7Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the “Basic
diagnostic flow
chart.”
Go to Step 7

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 PatternDiagnostic
1Warning light is actu-
ated normallyNormal
2Warning light is not litWarning light lighting circuit
trouble
Go to Chart B-1
3Warning light remains
ONDiagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.
4Warning light is actu-
ated while drivingDiagnostic 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:
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.
DTCs can be displayed also by TECH 2. Select mode
“F0: Diagnostic Trouble Codes” from Application
Menu.
1. How to start DTC display:
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.)
With IGN OFF, connect #12 terminal with #4
terminal or # 5 terminal (GND) . Then turn IGN ON.

5A–42
BRAKE CONTROL SYSTEM
4. Notes
If the following should occurs during Diagnostic
Trouble Code (DTC) display the display will be
discontinued. After initial check, the status that is
under the control of ABS will be returned :
– The vehicle starts (The wheels turn) or the brake
pedal is depressed.
Up to 3 different codes can be stored.
If the ABS should turn OFF due to an intermittent
defect, the system will be restored at the next key
cycle, if the initial check finds no abnormality (when
IGN is switched from OFF to ON).
5. An example of DTC display
Display of DTC 23
B05RW006
After displaying DTC 12 three times, one DTC after
another is displayed, starting with the most recent
one. (However, display is discontinued after about 5
minutes.)
B05RS005
The DTC 12 is displayed repeatedly. (display is
discontinued after about 5 minutes)

5A–57 BRAKE CONTROL SYSTEM
Unit Inspection Procedure
This section describes the following inspection
procedures referred to during “SYMPTOM DIAGNOSIS”
and “DIAGNOSIS BY ‘ABS’ WARNING LIGHT
ILLUMINATION PATTERN” :
without TECH 2with TECH 2
Wheel Speed Sensor Output InspectionChart C-1-1 to C-1-4Chart TC-1
Transmission SW InspectionChart C-2Chart TC-2
Chart C-1-1 FL Sensor Output Inspection Procedure
StepActionYe sNo
11. Turn the key off.
2. Disconnect EHCU connector.
3. Jack up the vehicle, With all four wheels off the ground.
Measure the AC voltage between EHCU connector terminals
while turning FL wheel at a speed of 1 RPS:
Is voltage between EHCU connector terminals 20 and 21 under
200 mV?
Go to Step 2
Ok.
Go to Step 3
21. Disconnect the wheel speed sensor.
2. Measure resistance between the wheel speed sensor
connector terminals 1 and 2.
Is resistance between connector (C-13) terminals 1 and 2 within
1.3k - 1.9k ohms?Connector is
faulty, or open or
short circuit in
harness between
wheel speed
sensor connector
and EHCU.
Inspect and
correct the
connector or
harness
Go to Step 3
Wheel speed
sensor is faulty.
Replace the
wheel speed
sensor.
Go to Step 3
3Reconnect all components and ensure all components are
properly mounted.
Was this step finished?Repeat the “Basic
diagnostic flow
chart.”
Go to Step 3

6A–6
ENGINE MECHANICAL
Rough Engine Idling or Engine Stalling
ConditionPossible causeCorrection
Trouble in fuel injection systemIdle air control valve defectiveReplace
Throttle shutting off incompleteCorrect or replace
Throttle position sensor circuit open
or shortedCorrect or replace
Fuel injector circuits open or shortedCorrect or replace
Fuel injectors damagedReplace
Fuel pump relay defectiveReplace
Mass Airflow Sensor circuit open or
poor connectionsCorrect or replace
Mass Airflow Sensor defectiveReplace
Manifold Absolute Pressure Sensor
circuit open or poor connectionsCorrect or replace
Manifold Absolute Pressure Sensor
defectiveReplace
Engine Coolant Temperature Sensor
circuit open or poor connectionsCorrect or replace
Engine Coolant Temperature Sensor
defectiveReplace
Intake Air Temperature sensor circuit
open or poor connectionsCorrect or replace
Intake Air Temperature sensor
defectiveReplace
Knock Sensor (KS) cable broken or
poor connectionsCorrect or replace
KS defectiveReplace
KS Module circuits open or groundCorrect or replace
KS Module defectiveReplace
Vehicle Speed Sensor circuit open or
shortedCorrect or replace
Vehicle Speed Sensor defectiveReplace
Trouble in emission control systemPowertrain Control Module defectiveReplace
Exhaust Gas Recirculation Valve
circuit open or poor connectionsCorrect or replace
Exhaust Gas Recirculation Valve
faultyReplace
Canister purge valve circuit open or
poor connectionsCorrect or replace
Canister purge valve defectiveReplace
Evaporative Emission Canister
Purge control valve defectiveReplace
Trouble in ignition systemRefer to “Hard Start”

6A–7
ENGINE MECHANICAL
Condition CorrectionPossible cause
OthersEngine lacks compressionRefer to “Hard Start”
Valve incorrectly seatedLap valve
Air Cleaner Filter cloggedReplace filter element
Valve timing incorrectReadjust
Idle air control valve brokenReplace
Fast idle solenoid defectiveReplace
Positive Crankcase Ventilation valve
defective or cloggedReplace
Rough Engine Running
ConditionPossible causeCorrection
Engine misfires periodicallyIgnition coil layer shortedReplace
Spark plugs foulingClean or install hotter type plug
Spark plug(s) insulator nose leakingReplace
Fuel injector(s) defectiveReplace
Powertrain control module faultyReplace
Engine knocks periodicallySpark plugs running too hotInstall colder type spark plugs
Powertrain control module faultyReplace
Engine lacks powerSpark plugs fouledClean
Fuel injectors defectiveReplace
Mass Airflow Sensor or Intake
Airflow Sensor circuit defectiveCorrect or replace
Manifold Absolute Pressure (MAP)
Sensor or Manifold Absolute
Pressure Sensor circuit defectiveCorrect or replace
Engine Coolant Temperature Sensor
or Engine Coolant Temperature
Sensor circuit defectiveCorrect or replace
Powertrain Control Module faultyReplace
Intake Air Temperature Sensor or
Intake Air Temperature Sensor
circuit defectiveCorrect or replace
Throttle Position Sensor or Throttle
Position Sensor circuit defectiveCorrect or replace
Knock Sensor or Knock Sensor
circuits defectiveCorrect or replace
Knock Sensor Module or Knock
Sensor Module circuits defectiveCorrect or replace

6A–8
ENGINE MECHANICAL
Hesitation
ConditionPossible causeCorrection
Hesitation on accelerationThrottle Position Sensor adjustment
incorrectReplace throttle valve assembly
Throttle Position Sensor circuit open
or shortedCorrect or replace
Excessive play in accelerator linkageAdjust or replace
Mass Airflow Sensor circuit open or
poor connectionsCorrect or replace
Mass Airflow Sensor defectiveReplace
Manifold Absolute Pressure (MAP)
Sensor circuit open or shortedCorrect or replace
MAP Sensor defectiveReplace
Intake Air Temperature (IAT) Sensor
circuit open or shortedCorrect or replace
Knock Sensor (KS) Circuit open or
poor connectionsCorrect or replace
KS defectiveReplace
KS Module circuits open or shortedCorrect or replace
KS Module defectiveReplace
IAT Sensor defectiveReplace
Hesitation at high speedsFuel tank strainer cloggedClean or replace
(Fuel pressure too low)Fuel pipe cloggedClean or replace
Fuel filter cloggedReplace
Defective fuel pump systemCheck and replace
Fuel Pressure Control Valve leakingReplace
Hesitation at high speeds
(Fuel injector not working normally)Power supply or ground circuit for
Multiport Fuel Injection System
shorted or openCheck and correct or replace
Fuel Injector defectiveReplace
Cable of Multiport Fuel Injection
System circuit open or poor
connectionsCorrect or replace

6A–10
ENGINE MECHANICAL
Engine Lacks Power
ConditionPossible causeCorrection
Trouble in fuel systemFuel Pressure Control Valve not
working normallyReplace
Fuel injector cloggedClean or replace
Fuel pipe cloggedClean
Fuel filter clogged or fouledReplace
Fuel pump drive circuit not working
normallyCorrect or replace
Fuel tank not sufficiently breathing
due to clogged Evaporative
Emission Control System circuitClean or replace
Water in fuel systemClean
Inferior quality fuel in fuel systemUse fuel of specified octane rating
Powertrain Control Module supplied
poor voltageCorrect circuit
Throttle Position Sensor cable
broken or poor connectionsCorrect or replace
Throttle Position Sensor defectiveReplace
Mass Airflow Sensor not working
normallyReplace
Manifold Absolute Pressure Sensor
not working normallyReplace
Intake Air Temperature Sensor not
working normallyReplace
Engine Coolant Temperature Sensor
circuit open or shortedCorrect or replace
Engine Coolant Temperature Sensor
defectiveReplace
Powertrain Control Module defectiveReplace
Trouble in intake or exhaust systemAir Cleaner Filter cloggedReplace filter element
Air duct kinked or flattenedCorrect or replace
Ignition failure————Refer to Hard Start Troubleshooting
Guide
Heat range of spark plug inadequateInstall spark plugs of adequate heat
range
Ignition coil defectiveReplace

6A–13
ENGINE MECHANICAL
Condition CorrectionPossible cause
Engine knockingPreignition due to use of spark plugs
of inadequate heat rangeInstall Spark Plugs of adequate heat
range
Carbon deposits in combustion
chambersClean
Fuel too low in octane ratingReplace fuel
Wide Open Throttle enrichment
system failureRefer to Section 6E
Selection of transmission gear
incorrectCaution operator of incorrect gear
selection
Engine overheatingRefer to “Engine Lacks Power”
OthersWater pump defectiveReplace
Drive belt slippingReplace auto tentioner or drive belt
Abnormal Combustion
ConditionPossible causeCorrection
Trouble in fuel systemFuel pressure control valve defectiveReplace
Fuel filter cloggedReplace
Fuel pump cloggedClean or replace
Fuel tank or fuel pipe cloggedClean or replace
Fuel injector cloggedClean or replace
Fuel pump relay defectiveReplace
Power supply cable for fuel pump
broken or poor connectionsReconnect, correct or replace
Mass Airflow (MAF) sensor circuit
open or defectiveCorrect or replace
MAF Sensor defectiveReplace
Manifold Absolute Pressure Sensor
circuit open or shortedCorrect or replace
Manifold Absolute Pressure Sensor
defectiveReplace
Engine Coolant Temperature (ECT)
Sensor circuit open or shortedCorrect or replace
ECT Sensor defectiveReplace
Throttle Position Sensor adjustment
incorrectReadjust
Throttle Position Sensor defectiveReplace
Throttle Position Sensor connector
poor connectionsReconnect
Vehicle Speed Sensor cable poor
connections or defectiveCorrect or replace
Vehicle Speed Sensor loosely fixedFix tightly
Vehicle Speed Sensor in wrong
contact or defectiveReplace
Powertrain Control Module cable
poor connections or defectiveCorrect or replace