battery OPEL FRONTERA 1998 Workshop Manual

6E–339 ENGINE DRIVEABILITY AND EMISSIONS
0005
PCM Components
The PCM is designed to maintain exhaust emission levels
to government mandated standards while providing
excellent driveability and fuel efficiency. The PCM
monitors numerous engine and vehicle functions via
electronic sensors such as the throttle position (TP)
sensor, heated oxygen sensor (HO2S), and vehicle
speed sensor (VSS). The PCM also controls certain
engine operations through the following:
Fuel injector control
Ignition control module
Knock sensor
Automatic transmission shift functions
Cruise control
A/C clutch control
PCM Voltage Description
The PCM supplies a buffered voltage to various switches
and sensors. It can do this because resistance in the
PCM is so high in value that a test light may not illuminate
when connected to the circuit. An ordinary shop
voltmeter may not give an accurate reading because the
voltmeter input impedance is too low. Use a 10-megohm
input impedance digital voltmeter (such as J 39200) to
assure accurate voltage readings.
The input/output devices in the PCM include
analog-to-digital converters, signal buffers, counters,
and special drivers. The PCM controls most components
with electronic switches which complete a ground circuit
when turned “ON.” These switches are arranged in
groups of 4 and 7, called either a surface-mounted quad
driver module (QDM), which can independently control up
to 4 output terminals, or QDMs which can independently
control up to 7 outputs. Not all outputs are always used.
PCM Input/Outputs
Inputs – Operating Conditions Read
Air Conditioning “ON” or “OFF”
Engine Coolant Temperature
Crankshaft Position
Exhaust Oxygen Content
Electronic Ignition
Manifold Absolute Pressure
Battery Voltage
Throttle Position
Vehicle Speed
Fuel Pump Voltage
Power Steering Pressure
Intake Air Temperature
Mass Air Flow
Engine Knock
Camshaft Position
Outputs – Systems Controlled
Exhaust Gas Recirculation (EGR)
Ignition Control
Fuel Control
Idle Air Control
Electric Fuel Pump
Air Conditioning
Diagnostics
– Malfunction Indicator Lamp (Service Engine Soon
lamp)
– Data Link Connector (DLC)
– Data Output
Transmission Control Module
Alternator Gain Control
PCM Service Precautions
The PCM is designed to withstand normal current draws
associated with vehicle operation. Avoid overloading any
circuit. When testing for opens and shorts, do not ground
or apply voltage to any of the PCM’s circuits unless
instructed to do so. These circuits should only be tested
Tech-2. The PCM should remain connected to the PCM
or to a recommended breakout box.
Reprogramming The PCM
The Trooper allow reprogramming of the PCM without
removing it from the vehicle . This provides a flexible and
cost-effective method of making changes in software
calibrations.
The service programming system (SPS) will not allow
incorrect software programming or incorrect calibration
changes.
Refer to the UBS 98model year Immobilizer Workshop
Manual.
Throttle Position (TP) Sensor
The throttle position (TP) sensor is a potentiometer
connected to the throttle shaft on the throttle body. The
PCM monitors the voltage on the signal line and
calculates throttle position. As the throttle valve angle is
changed (accelerator pedal moved), the TP sensor signal
also changes. At a closed throttle position, the output of

6E–340
ENGINE DRIVEABILITY AND EMISSIONS
the TP sensor is low. As the throttle valve opens, the
output increases so that at wide open throttle (WOT), the
output voltage should be above 4 volts.
The PCM calculates fuel delivery based on throttle valve
angle (driver demand). A broken or loose TP sensor may
cause intermittent bursts of fuel from an injector and
unstable idle because the PCM thinks the throttle is
moving. A hard failure in the TP sensor 5-volt reference
or signal circuits will set a DTC P0123. A hard failure with
the TP sensor ground circuit may set DTC P0123. Once
a DTC is set, the PCM will use an artificial default value
based on engine RPM and mass air flow for the throttle
position, and some vehicle performance will return. A
high idle may result when DTC P0123 is set. The PCM
can also detect a shifted TP sensor. The PCM monitors
throttle position and compares the actual TP sensor
reading to a predicted TP value calculated from engine
speed. If the PCM detects an out-of-range condition,
DTC P0121 will be set.
0021
Transmission Fluid Temperature (TFT)
Sensor
The transmission fluid temperature sensor is a thermistor
which changes its resistance based on the temperature of
the transmission fluid. For a complete description of the
TFT sensor, refer to
4L30-E Automatic Transmission
Diagnosis
.
A failure in the TFT sensor or associated wiring will cause
DTC P0712 or DTC P0713 to set. In this case, engine
coolant temperature will be substituted for the TFT
sensor value and the transmission will operate normally.
Transmission Range Switch
IMPORTANT:The vehicle should not be driven with the
transmission range switch disconnected; idle quality will
be affected.
The four inputs from the transmission range switch
indicate to the PCM which position is selected by the
transmission selector lever. This information is used for
ignition timing, EVAP canister purge, EGR and IAC valve
operation.For more information on the transmission on the
transmission range switch, refer to
4L30-E Automatic
Transmission
.
Vehicle Speed Sensor (VSS)
The PCM determines the speed of the vehicle by
converting a plusing voltage signal from the vehicle speed
sensor (VSS) into miles per hour. The PCM uses this
signal to operate the cruise control, speedometer, and the
TCC and shift solenoids in the transmission. For more
information on the TCC and shift solenoids, refer to
4L30-E Automatic Transmission.
0008
Use of Circuit Testing Tools
Do not use a test light to diagnose the powertrain
electrical systems unless specifically instructed by the
diagnostic procedures. Use Connector Test Adapter Kit J
35616 whenever diagnostic procedures call for probing
connectors.
Aftermarket Electrical and Vacuum
Equipment
Aftermarket (add-on) electrical and vacuum equipment is
defined as any equipment which connects to the vehicle’s
electrical or vacuum systems that is installed on a vehicle
after it leaves the factory. No allowances have been
made in the vehicle design for this type of equipment.
NOTE: No add-on vacuum equipment should be added
to this vehicle.
NOTE: Add-on electrical equipment must only be
connected to the vehicle’s electrical system at the battery
(power and ground).
Add-on electrical equipment, even when installed to
these guidelines, may still cause the powertrain system to
malfunction. This may also include equipment not
connected to the vehicle electrical system such as
portable telephones and radios. Therefore, the first step
in diagnosing any powertrain problem is to eliminate all
aftermarket electrical equipment from the vehicle. After

6E–341 ENGINE DRIVEABILITY AND EMISSIONS
this is done, if the problem still exists, it may be diagnosed
in the normal manner.
Electrostatic Discharge Damage
Electronic components used in the PCM are often
designed to carry very low voltage. Electronic
components are susceptible to damage caused by
electrostatic discharge. Less than 100 volts of static
electricity can cause damage to some electronic
components. By comparison, it takes as much as 4000
volts for a person to feel even the zap of a static
discharge.
TS23793
There are several ways for a person to become statically
charged. The most common methods of charging are by
friction and induction.
An example of charging by friction is a person sliding
across a vehicle seat.
Charge by induction occurs when a person with well
insulated shoes stands near a highly charged object
and momentary touches ground. Charges of the
same polarity are drained off leaving the person
highly charged with the opposite polarity. Static
charges can cause damage, therefore it is important
to use care when handling and testing electronic
components.
NOTE: To prevent possible electrostatic discharge
damage, follow these guidelines:
Do not touch the PCM connector pins or soldered
components on the PCM circuit board.
Do not touch the knock sensor module component
leads.
Do not open the replacement part package until the
part is ready to be installed.
Before removing the part from the package, ground
the package to a known good ground on the vehicle.
If the part has been handled while sliding across the
seat, while sitting down from a standing position, or
while walking a distance, touch a known good ground
before installing the part.
Upshift Lamp
Refer to Manual Transmission.
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 common chamber.
3. Through the cylinder head intake ports.
4. Into the cylinders.
055RV010
General Description (Fuel Metering)
Acceleration Mode
The PCM provides extra fuel when it detects a rapid
increase in the throttle position and the air flow.
Accelerator Controls
The accelerator control system is a cable-type system
with specific linkage adjustments.
Refer to
Cable Adjustment.
Battery Voltage Correction Mode
When battery voltage is low, the PCM will compensate for
the weak spark by increasing the following:
The amount of fuel delivered.
The idle RPM.
Ignition dwell time.
CMP Signal
The PCM uses this signal to determine the position of the
number 1 piston during its power stroke, allowing the

6E–343 ENGINE DRIVEABILITY AND EMISSIONS
constant measuring and adjusting of the air/fuel ratio, the
fuel injection system is called a “closed loop” system.
The PCM monitors signals from several sensors in order
to determine the fuel needs of the engine. Fuel is
delivered under one of several conditions called “modes.”
All modes are controlled by the PCM.
Fuel Pressure Regulator
The fuel pressure regulator is a diaphragm-operated
relief valve mounted on the fuel rail with fuel pump
pressure on one side and manifold pressure on the other
side. The fuel pressure regulator maintains the fuel
pressure available to the injector at three times
barometric pressure adjusted for engine load. It may be
serviced separate.
If the pressure is too low, poor performance and a DTC
P0131, DTC P0151,DTC P0171 or DTC P1171 will be the
result. If the pressure is too high, excessive odor and/or a
DTC P0132, DTC P0152,DTC P0172 or DTC P0175 will
be the result. Refer to
Fuel System Diagnosis for
information on diagnosing fuel pressure conditions.
0011
Fuel Pump Electrical Circuit
When the key is first turned “ON,” the PCM energizes the
fuel pump relay for two seconds to build up the fuel
pressure quickly. If the engine is not started within two
seconds, the PCM shuts the fuel pump off and waits until
the engine is cranked. When the engine is cranked and
the 58 X crankshaft position signal has been detected by
the PCM, the PCM supplies 12 volts to the fuel pump relay
to energize the electric in-tank fuel pump.
An inoperative fuel pump will cause a “no-start” condition.
A fuel pump which does not provide enough pressure will
result in poor performance.
Fuel Rail
The fuel rail is mounted to the top of the engine and
distributes fuel to the individual injectors. Fuel is
delivered to the fuel inlet tube of the fuel rail by the fuel
lines. The fuel goes through the fuel rail to the fuel
pressure regulator. The fuel pressure regulator maintainsa constant fuel pressure at the injectors. Remaining fuel
is then returned to the fuel tank.
055RW009
Idle Air Control (IAC) Valve
The purpose of the idle air control (IAC) valve is to control
engine idle speed, while preventing stalls due to changes
in engine load. The IAC valve, mounted in the throttle
body, controls bypass air around the throttle plate. By
moving the conical valve (pintle) in (to decrease air flow)
or out (to increase air flow), a controlled amount of air can
move around the throttle plate. If the RPM is too low, the
PCM will retract the IAC pintle, resulting in more air
moving past the throttle plate to increase the RPM. If the
RPM is too high, the PCM will extend the IAC pintle,
allowing less air to move past the throttle plate,
decreasing the RPM.
The IAC pintle valve moves in small steps called counts.
During idle, the proper position of the IAC pintle is
calculated by the PCM based on battery voltage, coolant
temperature, engine load, and engine RPM. If the RPM
drops below a specified value, and the throttle plate is
closed, the PCM senses a near-stall condition. The PCM
will then calculate a new IAC pintle valve position to
prevent stalls.
If the IAC valve is disconnected and reconnected with the
engine running, the idle RPM will be wrong. In this case,
the IAC must be reset. The IAC resets when the key is
cycled “ON” then “OFF.” When servicing the IAC, it
should only be disconnected or connected with the
ignition “OFF.”
The position of the IAC pintle valve affects engine start-up
and the idle characteristics of the vehicle. If the IAC pintle
is fully open, too much air will be allowed into the manifold.
This results in high idle speed, along with possible hard
starting and a lean air/fuel ratio. DTC P0507 or DTC
P1509 may set. If the IAC pintle is stuck closed, too little
air will be allowed in the manifold. This results in a low idle
speed, along with possible hard starting and a rich air/fuel
ratio. DTC P0506 or DTC P1508 may set. If the IAC
pintle is stuck part-way open, the idle may be high or low
and will not respond to changes in the engine load.

6E–346
ENGINE DRIVEABILITY AND EMISSIONS
Crankshaft position (58X reference).
Camshaft position (CMP) sensor.
Engine coolant temperature (ECT) sensor.
Throttle position (TP) sensor.
Knock signal (knock sensor).
Park/Neutral position (PRNDL input).
Vehicle speed (vehicle speed sensor).
PCM and ignition system supply voltage.
The crankshaft positron (CKP) sensor sends the
PCM a 58X signal related to the exact position of the
crankshaft.
TS22909
The camshaft position (CMP) sensor sends a signal
related to the position of the camshaft.
TS22910
The knock sensor tells the PCM if there is any
problem with pre-ignition or detonation. This
information allows the PCM to retard timing, if
necessary.
TS24037
Based on these sensor signals and engine load
information, the PCM sends 5V to each ignition coil.
060RW015
The PCM applies 5V signal voltage to the ignition coil
requiring ignition. This signal sets on the power transistor
of the ignition coil to establish a grounding circuit for the
primary coil, applying battery voltage to the primary coil.
At the ignition timing, the PCM stops sending the 5V
signal voltage. Under this condition the power transistor
of the ignition coil is set off to cut the battery voltage to the
primary coil, thereby causing a magnetic field generated
in the primary coil to collapse. On this moment a line of
magnetic force flows to the secondary coil, and when this
magnetic line crosses the coil, high voltage induced by

6E–349 ENGINE DRIVEABILITY AND EMISSIONS
Damage during re-gapping can happen if the gapping
tool is pushed against the center electrode or the
insulator around it, causing the insulator to crack.
When re-gapping a spark plug, make the adjustment
by bending only the ground side terminal, keeping the
tool clear of other parts.
”Heat shock” breakage in the lower insulator tip
generally occurs during several engine operating
conditions (high speeds or heavy loading) and may be
caused by over-advanced timing or low grade fuels.
Heat shock refers to a rapid increase in the tip
temperature that causes the insulator material to
crack.
Spark plugs with less than the recommended amount of
service can sometimes be cleaned and re-gapped , then
returned to service. However, if there is any doubt about
the serviceability of a spark plug, replace it. Spark plugs
with cracked or broken insulators should always be
replaced.
A/C Clutch Diagnosis
A/C Clutch Circuit Operation
A 12-volt signal is supplied to the A/C request input of the
PCM when the A/C is selected through the A/C control
switch.
The A/C compressor clutch relay is controlled through the
PCM. This allows the PCM to modify the idle air control
position prior to the A/C clutch engagement for better idle
quality. If the engine operating conditions are within their
specified calibrated acceptable ranges, the PCM will
enable the A/C compressor relay. This is done by
providing a ground path for the A/C relay coil within the
PCM. When the A/C compressor relay is enabled,
battery voltage is supplied to the compressor clutch coil.
The PCM will enable the A/C compressor clutch
whenever the engine is running and the A/C has been
requested. The PCM will not enable the A/C compressor
clutch if any of the following conditions are met:
The throttle is greater than 90%.
The engine speed is greater than 6315 RPM.
The ECT is greater than 119C (246F).
The IAT is less than 5C (41F).
The throttle is more than 80% open.
A/C Clutch Circuit Purpose
The A/C compressor operation is controlled by the
powertrain control module (PCM) for the following
reasons:
It improvises idle quality during compressor clutch
engagement.
It improvises wide open throttle (WOT) performance.
It provides A/C compressor protection from operation
with incorrect refrigerant pressures.
The A/C electrical system consists of the following
components:
The A/C control head.
The A/C refrigerant pressure switches.
The A/C compressor clutch.
The A/C compressor clutch relay.
The PCM.
A/C Request Signal
This signal tells the PCM when the A/C mode is selected
at the A/C control head. The PCM uses this to adjust the
idle speed before turning on the A/C clutch. The A/C
compressor will be inoperative if this signal is not
available to the PCM.
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.
057RW002
Linear EGR Valve
The main element of the system is the linear EGR valve.
The EGR valve feeds small amounts of exhaust gas back
into the combustion chamber. The fuel/air mixture will be
diluted and combustion temperatures reduced.
Linear EGR Control
The PCM monitors the EGR actual positron and adjusts
the pintle position accordingly. The uses information from
the following sensors to control the pintle position:
Engine coolant temperature (ECT) sensor.
Throttle position (TP) sensor.
Mass air flow (MAF) sensor.
Linear EGR Valve Operation and Results
of Incorrect Operation
The linear EGR valve is designed to accurately supply
EGR to the engine independent of intake manifold
vacuum. The valve controls EGR flow from the exhaust

6E–354
ENGINE DRIVEABILITY AND EMISSIONS
ILLUSTRATIONTOOL NO.
TOOL NAME
5-8840-2607-0
(J 41413)
EVAP Pressure/Purge
Diagnostic Station
5-8840-2608-0
(J 41416)
Ultrasonic Leak Detector
1. 5-8840-2607-0 (J-41413)EVAP Pressure/Purge
Diagnostic Station is a multipurpose tool which is
used to perform several diagnostic procedures for
enhanced emission testing. The station will
accommodate a nitrogen gas filled cylinder which is
used to pressurize the vehicle EVAP system for a
leakdown test and leak location test when a vehicle is
repaired for leakage in the enhanced evaporative
emission control system. It also has two additional
gauges (inches of mercury and inches of water) which
are used to measure both source vacuum and EVAP
canister purge vacuum to verify correct operation and
vapor flow within the canister purge circuit.
2. 5-8840-2608-0 (J-41416) Ultrasonic Leak Detector is
a microprocessor-based device used to detect leaks
in the enhanced evaporative emission control
system. The evaporative system is pressurized to 30
inches of water using the 5-8840-2607-0 (J-41413)
EVAP Pressure/Purge Diagnostic System. Small
leaks in the EVAP system will emit sound at a high
frequency undetectable by a human ear but
detectable with the 5-8840-2608-0 (J-41416). The
technician traces along the evaporative system and
can pinpoint leaks due to corroded lines, cracked
hoses, or a damaged EVAP component. The
detector includes a high quality set of headphones to
block out surrounding shop noise and the LED
sensitivity meter allows a visual reference for locating
leaks in conjunction with the audio output heard
through the headphones. Powered by (1) nine volt
battery.

6F–4ENGINE EXHAUST
Front Exhaust Pipe
Front Exhaust Pipe and Associated Parts
150RW063
Legend
(1) Front Exhaust Pipe RH Fixing Nuts
(2) Front Exhaust Pipe RH Fixing Bolts and Nuts
(3) O
2 Sensor Terminal Connector (for IGM)
(4) Front Exhaust Pipe LH Fixing Nuts(5) Front Exhaust Pipe LH Fixing Bolts and Nuts
(6) Front Exhaust Pipe LH
(7) Front Exhaust Pipe RH
(8) Three way Exhaust Pipe Fixing Bolts and Nuts
Removal
1. Disconnect battery ground cable.
2. Raise the vehicle and support with suitable safety
stands.
3. Disconnect O
2 sensor harness connector (3).
4. Remove front exhaust pipe fixing nuts and three way
Exhaust Pipe Fixing Bolts and Nuts (2)(5)(8).
5. Remove front exhaust pipe fixing three stud nuts from
exhaust manifold (1)(4).
6. Remove front exhaust pipe (6)(7).
Installation
1. Install front exhaust pipe (6)(7) and tighten three stud
nuts (1)(4) and nuts (2)(5)(8) to the specified torque.
To r q u e
Stud Nuts : 67 Nꞏm (6.8 Kgꞏm/49 lb ft)
Nuts : 43 Nꞏm (4.3 Kgꞏm/32 lb ft)
2. Reconnect O
2 sensor harness connector (3).

6F–5 ENGINE EXHAUST
Three Way Catalytic Converter
Removal
1. Disconnect battery ground cable.
2. Raise the vehicle and support with suitable safety
stands.
3. Remove three way exhaust pipe fixing bolts and nuts.
150RW065
Installation
1. Install three way catalytic converter between three
way exhaust pipe and silencer.
2. Tighten nuts to the specified torque.
Torque
Nuts : 43 Nꞏm (4.4 Kgꞏm/32 lb ft)

6F–6ENGINE EXHAUST
Exhaust Silencer
Exhaust Silencer and Associated Parts
E06RW031
Legend
(1) Exhaust Silencer
(2) Exhaust Silencer(3) Mounting Rubber
(4) Exhaust Silencer Fixing Nuts
(5) Exhaust Silencer Fixing Bolts
Removal
1. Disconnect battery ground cable.
2. Raise the vehicle and support with suitable safety
stands.
3. Remove exhaust silencer fixing nuts (4) then
disconnect rear exhaust pipe from exhaust silencer.
4. Remove exhaust silencer fixing nuts (5) then
disconnect exhaust silencer from three way exhaust
pipe.
5. Remove exhaust silencer mounting nuts from
chassis side then remove exhaust silencer (1)(2).
Installation
1. Install the exhaust silencer (1)(2) chassis side and
tighten nuts to the specified torque.
Nuts: 16 Nꞏm (1.6 Kgꞏm/12 lb ft)
2. Install the exhaust silencer and tighten nuts (5) on
front exhaust pipe to specified torque.
Nuts: 43 Nꞏm (4.4 Kgꞏm/32 lb ft)
3. Install the rear exhaust pipe and tighten fixing nuts on
exhaust silencer to specified torque.
Nuts: 43 Nꞏm (4.4 Kgꞏm/32 lb ft)