diagram OPEL FRONTERA 1998 Repair Manual

6E–24
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnosis
Strategy-Based Diagnostics
Strategy-Based Diagnostics
The strategy-based diagnostic is a uniform approach to
repair all Electrical/Electronic (E/E) systems. The
diagnostic flow can always be used to resolve an E/E
system problem and is a starting point when repairs are
necessary. The following steps will instruct the technician
how to proceed with a diagnosis:
1. Verify the customer complaint.
To verify the customer complaint, the technician
should know the normal operation of the system.
2. Perform preliminary checks.
Conduct a thorough visual inspection.
Review the service history.
Detect unusual sounds or odors.
Gather diagnostic trouble code information to
achieve an effective repair.
3. Check bulletins and other service information.
This includes videos, newsletters, etc.
4. Refer to service information (manual) system
check(s).
“System checks” contain information on a system
that may not be supported by one or more DTCs.
System checks verify proper operation of the
system. This will lead the technician in an
organized approach to diagnostics.
5. Refer to service diagnostics.
DTC Stored
Follow the designated DTC chart exactly to make an
effective repair.
No DTC
Select the symptom from the symptom tables. Follow the
diagnostic paths or suggestions to complete the repair.
You may refer to the applicable component/system check
in the system checks.
No Matching Symptom
1. Analyze the complaint.
2. Develop a plan for diagnostics.
3. Utilize the wiring diagrams and the theory of
operation.
Call technical assistance for similar cases where repair
history may be available. Combine technician knowledge
with efficient use of the available service information.
Intermittents
Conditions that are not always present are called
intermittents. To resolve intermittents, perform the
following steps:
1. Observe history DTCs, DTC modes, and freezeframe
data.2. Evaluate the symptoms and the conditions described
by the customer.
3. Use a check sheet or other method to identify the
circuit or electrical system component.
4. Follow the suggestions for intermittent diagnosis
found in the service documentation.
Most scan tools, such as the Tech 2 and the DVM, have
data-capturing capabilities that can assist in detecting
intermittents.
No Trouble Found
This condition exists when the vehicle is found to operate
normally. The condition described by the customer may
be normal. Verify the customer complaint against another
vehicle that is operating normally. The condition may be
intermittent. Verify the complaint under the conditions
described by the customer before releasing the vehicle.
1. Re-examine the complaint.
When the complaint cannot be successfully found or
isolated, a re-evaluation is necessary. The complaint
should be re-verified and could be intermittent as
defined in
Intermittents, or could be normal.
2. Repair and verify.
After isolating the cause, the repairs should be made.
Validate for proper operation and verify that the
symptom has been corrected. This may involve road
testing or other methods to verify that the complaint
has been resolved under the following conditions:
Conditions noted by the customer.
If a DTC was diagnosed, verify a repair by
duplicating conditions present when the DTC was
set as noted in the Failure Records or Freeze
Frame data.
Verifying Vehicle Repair
Verification of the vehicle repair will be more
comprehensive for vehicles with OBD system
diagnostics. Following a repair, the technician should
perform the following steps:
IMPORTANT:Follow the steps below when you verify
repairs on OBD systems. Failure to follow these steps
could result in unnecessary repairs.
1. Review and record the Failure Records and the
Freeze Frame data for the DTC which has been
diagnosed (Freeze Frame data will only be stored for
the MIL (“Check Engine” lamp) has been requested).
2. Clear the DTC(s).
3. Operate the vehicle within conditions noted in the
Failure Records and Freeze Frame data.
4. Monitor the DTC status information for the specific
DTC which has been diagnosed until the diagnostic
test associated with that DTC runs.

6E–176
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Symptom Diagnosis
Preliminary Checks
Before using this section, perform the “On–Board
Diagnostic (OBD) System Check” and verify all of the
following items:
The powertrain control module (ECM) and
malfunction indicator lamp (MIL) (CHECK ENGINE
lamp) are operating correctly.
There are no DTC(s) stored.
Tech–2 data is within normal operating range. Refer
to
Typical Scan Data Values.
Verify the customer complaint and locate the correct
symptom in the table of contents. Perform the
procedure included in the symptom chart.
Visual/Physical Check
Several of the symptom procedures call for a careful
visual/physical check. This can lead to correcting a
problem without further checks and can save valuable
time.
This check should include the following items:
ECM grounds for cleanliness, tightness and proper
location.
Vacuum hoses for splits, kinks, and proper
connections, as shown on the “Vehicle Emission
Control Information” label. Check thoroughly for any
type of leak or restriction.
Air intake ducts for collapsed or damaged areas.
Injector wires for cracking, hardness, and carbon
tracking.
Wiring for proper connections, pinches and cuts.
Intermittents
IMPORTANT:An intermittent problem may or may not
turn on the malfunction indicator lamp (MIL) or store a
DTC. DO NOT use the Diagnostic Trouble Code (DTC)
charts for intermittent problems. The fault must be
present to locate the problem.
Most intermittent problems are caused by faulty electrical
connections or wiring. Perform a careful visual/physical
check for the following conditions:
Poor mating of the connector halves or a terminal not
fully seated in the connector (backed out).
Improperly formed or damaged terminal.
All connector terminals in the problem circuit should
be carefully checked for proper contact tension.
Poor terminal–to–wire connection. This requires
removing the terminal from the connector body to
check.
Road test the vehicle with a Digital Multimeter
(5-8840-0285-0) connected to a suspected circuit. An
abnormal voltage when the malfunction occurs is a good
indication that there is a fault in the circuit being
monitored.
Use a scan tool to help detect intermittent conditions. The
scan tools have several features that can be used to
locate an intermittent condition. Use the following feature
to find intermittent faults:
Using a Tech–2 “Freeze Frame” buffer or “Failure
Records” buffer can aid in locating an intermittent
condition. Review and record the information in the
freeze frame or failure record associated with the
intermittent DTC being diagnosed. The vehicle can
be driven within the conditions that were present
when the DTC originally set.
To check for loss of diagnostic code memory, disconnect
the MAP sensor and idle the engine until the MIL (CHECK
ENGINE lamp) comes on. DTC P0107 should be stored
and kept in memory when the ignition is turned “OFF.” If
not, the ECM is faulty. When this test is completed, make
sure that you clear the DTC P0107 from memory.
An intermittent MIL (CHECK ENGINE lamp) with no
stored DTC may be caused by the following:
MIL (CHECK ENGINE lamp) wire to ECM shorted to
ground.
Poor ECM grounds. Refer to the ECM wiring
diagrams.
Check for improper installation of electrical options such
as lights, cellular phones, etc.
Check for an open diode across the A/C compressor
clutch and check for other open diodes (refer to wiring
diagrams in
Electrical Diagnosis).
If problem has not been found, refer to
ECM Connector
Symptom
tables.

6E–179 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Surges and/or Chuggles Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Engine power variation under steady throttle or cruise.
Feels like the vehicle speeds up and slows down with
no change in the accelerator pedal.
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—Verify repairGo to Step 3
3Was a visual/physical check performed?
—Go to Step 4
Go to Visual/
Physical
Check
4Be sure that the driver understands transmission
torque converter clutch and A/C compressor operation
as explained in the owner’s manual.
Inform the customer how the TCC and the A/C clutch
operate.
Is the customer experiencing a normal condition?
—System OKGo to Step 5
51. Check the priming pump. Refer to Fuel System.
2. If a problem is found, operate the priming pump.
Was a problem found?
—Verify repairGo to Step 6
61. Injector Test
Operate the each injector by Tech 2 with the
ignition “ON” and check if the working noise
confirm.
2. If a problem is found, check the harness and repair
as necessary.
Is the action complete?
—Verify repairGo to Step 7
71. Check ECM grounds for the cleanliness, tightness
and proper locations. Refer to the ECM wiring
diagrams in
Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 8
81. Check AP sensor connections.
2. If a problem is found, replace the faulty terminals as
necessary. Refer to
Electrical Diagnosis for wiring
repair procedures.
Was a problem found?
—Verify repairGo to Step 9
91. Visually/physically check vacuum hoses for splits,
kinks, and proper connections and routing as
shown on the “Vehicle Emission Control
Information” label.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 10

6E–181 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Lack of Power, Sluggish or Spongy Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Engine delivers less than expected power. Little or no
increase in speed when accelerator pedal is pushed
down part-way.
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—Verify repairGo to Step 3
3Was a visual/physical check performed?
—Go to Step 4
Go to Visual/
Physical
Check
41. Remove and check the air filter element for dirt or
restrictions. Refer to
Air Intake System in
On-Vehicle Service.
2. Replace the air filter element if necessary.
Was a repair required?
—Verify repairGo to Step 5
51. Check AP sensor system. Refer to AP sensor
diagnostic
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 6
61. Check for water-or alcohol-contaminated fuel.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 7
71. Using a Tech 2, Injector test.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 8
81. Check the ECM grounds for the cleanliness,
tightness and proper locations. Refer to the ECM
wiring diagrams in
Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 9
91. Check the exhaust system for possible restriction:
Inspect the exhaust system for damaged or
collapsed pipes.
Inspect the muffler for heat distress or possible
internal failure.
Check for a possible plugged catalytic
converter by checking the exhaust system
back pressure. Refer to
Restricted Exhaust
System Check
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 10
101. Check the torque converter clutch (TCC) for proper
operation. Refer to
Transmission Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 11

6E–183 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Rough, Unstable, or Incorrect Idle, Stalling Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Engine runs unevenly at idle. If severe, the engine or
vehicle may shake. Engine idle speed may vary in
RPM. Either condition may be severe enough to stall
the engine.
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—Go to Step 6Go to Step 3
3Was a visual/physical check performed?
—Go to Step 4
Go to Visual/
Physical
Check
41. Check the ECM grounds for cleanliness, tightness
and proper routing. Refer to the ECM wiring
diagrams in
Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 5
51. Check for incorrect idle speed. Ensure that the
following conditions are present:
The engine is fully warm.
The accessories are “OFF.”
2. Using a Tech 2, monitor the AP position.
Is the AP position within the specified values?
0%Go to Step 10Go to Step 9
61. Visually/physically inspect for the following
conditions:
Restricted air intake system. Check for a
possible collapsed air intake duct, restricted
air filter element, or foreign objects blocking
the air intake system.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 7
71. Injector Test
Operate the each injector by Tech 2 with the
ignition “ON” and check if the working noise
confirm.
2. If a problem is found, check the harness or replace
the injector.
Is the action complete?
—Verify repairGo to Step 8
81. Check the transmission range switch circuit. Use a
Tech 2 and be sure the Tech 2 indicates that the
vehicle is in drive with the gear selector in drive or
overdrive.
2. If a problem is found, diagnose and repair the
transmission range switch as necessary (Refer to
Automatic Transmission Diagnosis).
Was a problem found?
—Verify repairGo to Step 9

6E–189 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Cuts Out, Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Steady pulsation or jerking that follows engine speed;
usually more pronounced as engine load increases.
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—Go to Step 7Go to Step 3
3Was a visual/physical check performed?
—Go to Step 4
Go to Visual/
Physical
Check
41. Check the ECM grounds for clearness, tightness
and proper routing. Refer to the ECM wiring
diagrams in
Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 5
51. Check for incorrect idle speed. Ensure that the
following conditions are present:
The engine is fully warm.
The accessories are “off.”
2. Using a Tech 2, monitor the AP position.
Is the AP position within the specified values?
0%Go to Step 6Go to Step 7
61. Visually/physically inspect for the following
conditions:
Restricted air intake system. Check for a
possible collapsed air intake duct, restricted
air filter element, or foreign objects blocking
the air intake system.
Check the Throttle body.
Large vacuum leak. Check for a condition that
causes a large vacuum leak, such as an
incorrectly installed or faulty VSV or brake
booster hose disconnected .
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 7
7Using a Tech 2, monitor the AP angle with the engine
idling.
Is the AP angle at the specified value and steady?
0%Go to Step 8
Refer to DTC
P0123
for
further
diagnosis
81. Check the transmission range switch circuit. Use a
Tech 2 and be sure the Tech 2 indicates that the
vehicle is in drive with the gear selector in drive or
overdrive.
2. If a problem is found, diagnose and repair the
transmission range switch as necessary.
Was a problem found?
—Verify repairGo to Step 9

6E–217 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Throttle Body (TB)
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the cover of the intercooler.
035RW051
3. Remove the bolts and the left side bracket to the
intercooler.
4 . R e m o v e t h e a i r d u c t w i t h b r a c k e t f r o m t h e i n t e r c o o l e r.
035RW086
5. Remove the throttle body assembly from the intake
manifold.
6. Disconnect the ITP sensor electrical connector.
Installation Procedure
NOTE: Do not use solvent of any type when you clean the
gasket surfaces on the intake manifold and the throttle
body assembly. The gasket surfaces and the throttle body
assembly may be damaged as a result.
If the throttle body gasket needs to be replaced,
remove any gasket material that may be stuck to the
mating surfaces of the manifold.
Do not leave any scratches in the aluminum casting.
1. Install the throttle body assembly to the intake
manifold and the air duct with bracket between
throttle body and intercooler.
Torque: 20 Nꞏm (14 Ib ft)
035RW086
2. Connect the ITP sensor electrical connector and
throttle motor control connector.
3. Install the bracket to the intercooler.
4. Install the cover of intercooler.
5. Connect the negative battery cable.
Air Conditioning (A/C) Relay
Removal Procedure
1. Remove the fuse and relay box cover from under the
hood.
2. Consult the diagram on the cover to determine which
is the correct relay.
3. Pull the relay straight up and out of the fuse and relay
box.
Installation Procedure
1. Insert the relay into the correct place in the fuse and
relay box with the catch slot facing forward.
2. Press down until the catch engages.
An audible “click” will be heard.
3. Install the fuse and relay box cover.
Exhaust Gas Recirculation
(EGR) Vacuum Switch Valve
(VSV)
Removal Procedure
1. Disconnect the negative battery cable.

6E–225 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
General Description
(ECM and Sensors)
57X Reference ECM Input
The engine control module (ECM) uses this signal from
the crankshaft position (CKP) sensor to calculate engine
RPM and crankshaft position at all engine speeds. The
ECM also uses the pulses on this circuit to initiate injector
pulses. If the ECM receives no pulses on this circuit, DTC
P0337 will set. The engine will not start and run without
using the 57X reference signal.
A/C Request Signal
This signal tells the ECM when the A/C mode is selected
at the A/C control head.
Refer to
A/C Clutch Circuit Diagnosis for A/C wiring
diagrams and diagnosis for the A/C electrical system.
Crankshaft Position (CKP) Sensor
The crankshaft position (CKP) sensor provides a signal
used by the engine control module (ECM) to calculate the
ignition sequence. The CKP sensor initiates the 57X
reference pulses which the ECM uses to calculate RPM
and crankshaft position.
Refer to
Electronic Ignition System for additional
information.
Camshaft Position (CMP) Sensor and
Signal
The camshaft position (CMP) sensor sends a CMP signal
to the ECM. The ECM uses this signal as a “cylinder
distinction” to trigger the injectors in the power order. If the
ECM detects an incorrect CMP signal while the engine is
running, DTC P0341 will set, and the ECM triggers the
injectors in the power order.
Refer to
DTC P0341.
Engine Coolant Temperature (ECT) Sensor
The engine coolant temperature (ECT) sensor is a
thermistor (a resistor which changes value based on
temperature) mounted in the engine coolant stream. Low
coolant temperature produces a high resistance of
100,000 ohms at –40
C (–40F). High temperature
causes a low resistance of 70 ohms at 130
C (266F).
The ECM supplies a 5-volt signal to the ECT sensor
through resistors in the ECM and measures the voltage.
The signal voltage will be high when the engine is cold and
low when the engine is hot. By measuring the voltage, the
ECM calculates the engine coolant temperature. Engine
coolant temperature affects most of the systems that the
ECM controls.
The Tech 2 displays engine coolant temperature in
degrees. After engine start-up, the temperature should
rise steadily to about 85
C (185F). It then stabilizes
when the thermostat opens. If the engine has not been
run for several hours (overnight), the engine coolanttemperature and intake air temperature displays should
be close to each other. A hard fault in the engine coolant
sensor circuit will set DTC P0117 or DTC P0118.
0016
Electrically Erasable Programmable Read
Only Memory (EEPROM)
The electrically erasable programmable read only
memory (EEPROM) is a permanent memory chip that is
physically soldered within the ECM. The EEPROM
contains the program and the calibration information that
the ECM needs to control powertrain operation.
Unlike the PROM used in past applications, the EEPROM
is not replaceable. If the ECM is replaced, the new ECM
will need to be programmed. Equipment containing the
correct program and calibration for the vehicle is required
to program the ECM.
Intake Air Temperature (IAT) Sensor
The intake air temperature (IAT) sensor is a thermistor
which changes its resistance based on the temperature of
air entering the engine. Low temperature produces a high
resistance of 100,000 ohms at –40
C (–40F). High
temperature causes low resistance of 70 ohms at 130
C
(266
F) . The ECM supplies a 5-volt signal to the sensor
through a resistor in the ECM and monitors the signal
voltage. The voltage will be high when the incoming air is
cold. The voltage will be low when the incoming air is hot.
By measuring the voltage, the ECM calculates the
incoming air temperature.
The Tech 2 displays the temperature of the air entering
the engine. The temperature should read close to the
ambient air temperature when the engine is cold and rise
as underhood temperature increases. If the engine has
not been run for several hours (overnight), the IAT sensor
temperature and engine coolant temperature should read
close to each other. A fault in the IAT sensor circuit will set
DTC P0112 or DTC P0113.

6E–228
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
General Description (Air Induction)
Air Induction System
The air induction system filters contaminants from the
outside air, and directs the progress of the air as it is
drawn into the engine. A remote-mounted air cleaner
prevents dirt and debris in the air from entering the
engine. The air duct assembly routes filtered air to the
throttle body. Air enters the engine by to following steps:
1. Through the throttle body.
2. Into the intake manifold.
3. Through the cylinder head intake ports.
4. Into the cylinders.
General Description (Fuel Metering)
Deceleration Mode
The ECM reduces the amount of fuel injected when it
detects a decrease in the Accelerator position.
Fuel Injector
Fuel injector comprises the solenoid, hydraulic line, and
fuel line. Fuel injection is controlled by the continuity time
signal and continuity start timing signal from ECM to the
solenoid
ECM determines the running conditions of engine by
input signals such as engine speed. Accelerator throttle
valve opening, and engine coolant temperature, thereby
to send the solenoid the best suited signal to the engine
status. When current is carried to the solenoid, the
armature opens the poppet valve to alow high pressure oil
to run into the injector. Under the pressure of the oil, the
piston and plunger are depressed to compress the fuel in
the combustion chamber of the plunger. Specifically, the
pressure of the fuel compressed is increased by a piston
top/ plunger bottom area ratio over the pressure of high
pressure oil, thereby lifting the fuel nozzle end needle for
injecting fuel.
Fuel Metering System Components
The fuel metering system is made up of the following
parts:
The fuel injectors.
The intake throttle body.
The Accelerator position (AP) sensor
The ECM.
The crankshaft position (CKP) sensor.
The camshaft position (CMP) sensor.
Basic System Operation
Fuel is supplied through fuel filter to the fuel pump.
The fuel pump is installed to the oil pump, and fuel is
forced, through the fuel pump outlet, pipe and cylinder
head inside, into the fuel injector.
An orifice is provided at the rear fuel outlet of cylinder
head to control the pressure of oil.The injector is controlled by ECM which gives
opening/closing commands to the solenoid installed on
the top of the injector. Opening/closing operation of the
pressurized engine oil circuit of the injector controls fuel
injection quantity, fuel injection timing, etc.
A/C Clutch Diagnosis
A/C Request Signal
This signal tells the ECM when the A/C mode is selected
at the A/C control head. The ECM uses this to adjust the
idle speed.
Refer to
A/C Clutch Circuit Diagnosis for A/C wiring
diagrams and diagnosis for A/C electrical system.
General Description Exhaust Gas
Recirculation (EGR) System
EGR Purpose
The exhaust gas recirculation (EGR) system is use to
reduce emission levels of oxides of nitrogen (NOx). NOx
emission levels are caused by a high combustion
temperature. The EGR system lowers the NOx emission
levels by decreasing the combustion temperature.
The ECM uses information from the following sensors to
control EGR valve boost pressure.
ECT
ITP
Engine Speed
AP sensor

TRANSMISSION CONTROL SYSTEM (4L30–E)7A1–3
Electronic Control Diagram
C07RW052