Opel Frontera UE. Manual - part 252

6E1–306

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

0012

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 about 100,000

at –40

C (–104

F). High

temperature causes low resistance of about 70

130

C (266

F). The ECM supplies a 5–volt signal to the

sensor through a resistor internal to the ECM, and then
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 IAT sensor
signal is used to adjust spark timing according to the
incoming air density.
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 failure in the IAT sensor circuit will
set DTC P0112, or DTC P0113.

Linear Exhaust Gas Recirculation (EGR)
Control

The ECM monitors the exhaust gas recirculation (EGR)
actual position and adjusts the pintle position accordingly.
The ECM uses information from the following sensors to
control the pintle position:

Engine coolant temperature (ECT) sensor.

Throttle position (TP) sensor.

Manifold Absolute Pressure (MAP) sensor.

0017

Manifold Absolute Pressure (MAP) Sensor

The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum). The
MAP sensor signal voltage to the ECM varies from below
2 volts at idle (high vacuum) to above 4 volts with the
ignition ON, engine not running or at wide–open throttle
(low vacuum).
The MAP sensor is used to determine the following:

Manifold pressure changes while the linear EGR flow
test diagnostic is being run. Refer to DTC P0401.

Engine vacuum level for other diagnostics.

Barometric pressure (BARO).

If the ECM detects a voltage that is lower than the
possible range of the MAP sensor, DTC P0107 will be set.
A signal voltage higher than the possible range of the
sensor will set DTC P0108. The ECM can detect a shifted
MAP sensor. The ECM compares the MAP sensor signal
to a calculated MAP based on throttle position and
various engine load factors.

014RX013

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X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Engine Control Module (ECM)

The engine control module (ECM) is located in the
passenger compartment below the center console. The
ECM controls the following:

Fuel metering system.

Ignition timing.

On–board diagnostics for powertrain functions.

The ECM constantly observes the information from
various sensors. The ECM controls the systems that
affect vehicle performance. The ECM performs the
diagnostic function of the system. It can recognize
operational problems, alert the driver through the Check
Engine lamp, and store diagnostic trouble codes (DTCs).
DTCs identify the problem areas to aid the technician in
making repairs.

014RX002

ECM Function

The ECM supplies either 5 or 12 volts to power various
sensors or switches. The power is supplied through
resistors in the ECM which are so high in value that a test
light will not light when connected to the circuit. In some
cases, even an ordinary shop voltmeter will not give an
accurate reading because its resistance is too low.
Therefore, a digital voltmeter with at least 10 meg

input

impedance is required to ensure accurate voltage
readings. Tool J 39200 meets this requirement.
The ECM controls output circuits such as the injectors,
IAC, cooling fan relays, etc., by controlling the ground or
the power feed circuit through transistors or through
either of the following two devices:

Output Driver Module (ODM)

Quad Driver Module (QDM)

ECM Components

The ECM is designed to maintain exhaust emission levels
to government mandated standards while providing
excellent driveability and fuel efficiency. The ECM
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 ECM also controls certain
engine operations through the following:

Fuel injector control

Ignition control module

Evaporative emission (EVAP) purge

A/C clutch control

ECM Voltage Description

The ECM supplies a buffered voltage to various switches
and sensors. It can do this because resistors in the ECM
which are 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 ECM include
analog–to–digital converters, signal buffers, counters,
and special drivers. The ECM 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 quad driver module (QDM),
which can independently control up to 4 output terminals,
or Output Driver Module (ODM) which can independently
control up to 7 outputs. Not all outputs are always used.

ECM Inputs/Outputs

Inputs – Operating Conditions Read

Air Conditioning Compressor Clutch ON or OFF

Engine Coolant Temperature

Crankshaft Position

Exhaust Oxygen Content

Manifold Absolute Pressure

Battery Voltage

Throttle Position

Fuel Tank Vapor Pressure

Fuel Tank Level

Exhaust Gas Recirculation (EGR) Feedback

Knock

Vehicle Speed

Fuel Pump Voltage

Power Steering Pressure

Intake Air Temperature

Camshaft Position

Outputs – Systems Controlled

EVAP Canister Purge Solenoid

Exhaust Gas Recirculation (EGR)

Ignition Control

Fuel Injector Control

Idle Air Control

Coolant Fan Relays

Electric Fuel Pump Relay Compressor Clutch Relay

Air Conditioning

6E1–308

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Diagnostics
– OBD II Malfunction Indicator Lamp (Check Engine

lamp)

– Data Link Connector (DLC)
– Data Output

Tachometer Signal

ECM Service Precautions

The ECM is designed to withstand normal current draws
associated with vehicle operation. Avoid over loading any
circuit. When testing for opens and shorts, do not ground
or apply voltage to any of the ECM’s circuits unless
instructed to do so. These circuits should only be tested
using digital voltmeter J 39200. The ECM should remain
connected to the ECM or to a recommended breakout
box.

014RX002

Throttle Position (TP) Sensor

The throttle position (TP) sensor is a potentiometer
connected to the throttle shaft on the throttle body. The
ECM 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
the TP sensor is about 0.25 volts. As the throttle valve
opens, the output increases so that at wide open throttle
(WOT), the output voltage should be about 4.75 volts.
The ECM 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 ECM thinks the throttle is
moving. A hard failure in the TP sensor 5–volt reference
or signal circuits will set either a DTC P0122 or DTC
P0123. A hard failure with the TP sensor ground circuit
may set DTC P0123 and DTC P0122. Once a DTC is set,
the ECM 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 either DTC P0122 or DTC P0123 is set. The
ECM can detect intermittent TP sensor faults.

101RX003

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 ECM 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 range switch,
refer to 4L30–E Automatic Transmission.

Vehicle Speed Sensor (VSS)

The ECM determines the speed of the vehicle by
converting a pulsing voltage signal from the vehicle speed
sensor (VSS) into miles per hour. The ECM uses this
signal to operate the speedometer.

0008

Use of Circuit Testing Tools

Do not use a test light to diagnose the powertrain
electrical systems unless specifically instructed by the

6E1–309

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

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
this is done, if the problem still exists, it may be diagnosed
in the normal manner.

Electrostatic Discharge Damage

Electronic components used in the ECM 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.
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 momentarily 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.

TS23793

NOTE: To prevent possible electrostatic discharge
damage, follow these guidelines:

Do not touch the ECM connector pins or soldered
components on the ECM circuit board.

Do not touch any electronic 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.

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 the following steps:

1. Through the throttle body.
2. Into the intake manifold.
3. Through the cylinder head intake ports.
4. Into the cylinders.

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