1998 OPEL FRONTERA Back

6E–58
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0108 (Flash DTC 34)
MAP Sensor Circuit High Voltage
060RW134
Circuit Description
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum).
The ECM monitors the MAP signals for voltages outside
the normal range of the MAP sensor. If the ECM detects a
MAP signal voltage that is excessively high, DTC P0108
will be set.
Action Taken When the DTC Sets
The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
DTC P0108 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:
Turn on the ignition switch and stop the engine. At this
time, the boost pressure will be equal to the
atmospheric pressure and the signal voltage will
increase.
Poor connection at ECM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
MAP display on the Tech 2 while moving connectors
and wiring harnesses related to the sensor. A change
in the display will indicate the location of the fault.
If DTC P0108 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set. If
it is determined that the DTC occurs intermittently.

6E–60
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0112 (Flash DTC 23)
IAT Sensor Circuit Low Voltage
060RW129
Circuit Description
The Intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The Engine Control Module ECM applies 5 volts
through a pull-up resistor to the IAT sensor. When the
intake air is cold, the sensor resistance is high and the
ECM will monitor a high signal voltage on the IAT signal
circuit. If the intake air is warm, the sensor resistance is
lower, causing the ECM to monitor a lower voltage. DTC
P0112 will set when the ECM detects an excessively low
signal voltage on the Intake air temperature sensor signal
circuit.
Action Taken When the DTC Sets
The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
DTC P0112 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
IAT display on the Tech 2 while moving connectors and
wiring harnesses related to the IAT sensor. A change
in the IAT display will indicate the location of the fault.
If DTC P0112 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E–62
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0113 (Flash DTC 23)
IAT Sensor Circuit High Voltage
060RW129
Circuit Description
The intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The Engine Control Module ECM applies 5 volts
through a pull-up resistor to the IAT sensor. When the
intake air is cold, the sensor resistance is high and the
ECM will monitor a high signal voltage on the IAT signal
circuit. If the intake air is warm, the sensor resistance is
lower causing the ECM to monitor a lower voltage. DTC
P0113 will set when the ECM detects an excessively high
signal voltage on the intake air temperature sensor signal
circuit.
Action Taken When the DTC Sets
The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
DTC P0113 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
IAT display on the Tech 2 while moving connectors and
wiring harnesses related to the IAT sensor. A change
in the IAT display will indicate the location of the fault.
If DTC P0113 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E–65 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0117 (Flash DTC 14)
ECT Sensor Low Voltage
060RW129
Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted on a coolant crossover pipe at the
rear of the engine. The Engine Control Module ECM
applies a voltage (about 5 volts) through a pull-up resistor
to the ECT signal circuit. When the engine coolant is cold,
the sensor (thermistor) resistance is high, therefore the
ECM will measure a high signal voltage. As the engine
coolant warms, the sensor resistance becomes lower,
and the ECT signal voltage measured at the ECM drops.
Action Taken When the DTC Sets
The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
DTC P0117 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM – Inspect harness connectors
for backed-out terminals, improper mating, brokenlocks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
ECT display on the Tech 2 while moving connectors
and wiring harnesses related to the ECT sensor. A
change in the ECT display will indicate the location of
the fault.
If DTC P0117 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
If it is determined that the DTC occurs intermittently.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Verifies that the fault is present.
3. If DTC P0117 can be repeated only by duplicating
the Failure Records conditions, refer to the
“Temperature vs. Resistance Values” table. The
table may be used to test the ECT sensor at various
temperatures to evaluate the possibility of a
“shifted” sensor that may be shorted above or below
a certain temperature. If this is the case, replace
the ECT sensor. If the ECT sensor appears to be
OK, the fault is intermittent; refer to
Diagnostic Aids.

6E–67 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0118 (Flash DTC 14)
ECT Sensor High Voltage
060RW129
Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted in on a coolant crossover pipe at the
rear of the engine. The Engine Control Module ECM
applies a voltage (about 5 volts) through a pull-up resistor
to the ECT signal circuit. When the engine coolant is cold,
the sensor (thermistor) resistance is high, therefore the
ECM will measure a high signal voltage. As the engine
coolant warms, the sensor resistance becomes less, and
the ECT signal voltage measured at the ECM drops.
Action Taken When the DTC Sets
The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
DTC P0118 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
ECT display on the Tech 2 while moving connectors
and wiring harnesses related to the ECT sensor. A
change in the ECT display will indicate the location of
the fault.
If DTC P0118 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E–70
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0121 (Flash DTC 33)
AP Sensor Rationality
060RW134
Circuit Description
The accel position (AP) sensor circuit provides a voltage
signal that changes relative to throttle blade angle.
The AP signal is one of the most important inputs used by
the Engine Control Module ECM for fuel volume control
and many of the ECM-controlled outputs. If the ECM
detects an out-of-range condition, DTC P0121 will set.
Action Taken When the DTC Sets
The ECM will illuminate the malfunction indicator lamp
(MIL) after fault is detected.
The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
DTC P0121 can be cleared by using the Tech 2 “Clear
info ” function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
ECT display on the Tech 2 while moving connectors
and wiring harnesses related to the sensor. A change
in the display will indicate the location of the fault.
If DTC P0121 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E–72
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0122 (Flash DTC 21)
AP Sensor Low Voltage
060RW134
Circuit Description
The accelerator position (AP) sensor circuit provides a
voltage signal that changes relative to throttle blade
angle.
The AP signal is used by the Engine Control Module ECM
for fuel volume control and many of the ECM-controlled
outputs.
Action Taken When the DTC Sets
The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
DTC P0122 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
throttle position display on the Tech 2 while moving
connectors and wiring harnesses related to the TP
sensor. A change in the display will indicate the
location of the fault.
If DTC P0122 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
DTC P0122 –AP Sensor Low Voltage
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
2Check the AP sensor signal circuit.
Was the AP sensor signal circuit open or darmage?
—
Replace the
APS circuit
Go to Step 3

6E–75 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0123 (Flash DTC 21)
AP Sensor High Voltage
060RW134
Circuit Description
The accelerator position (AP) sensor circuit provides a
voltage signal that changes relative to throttle blade
angle.
The TP signal is one of the most important inputs used by
the Engine Control Module ECM for fuel volume control
and many of the ECM-controlled outputs.
Action Taken When the DTC Sets
The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
DTC P0123 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM – Inspect harness connectors
for backed-out terminals, improper mating, brokenlocks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
AP sensor display on the Tech 2 while moving
connectors and wiring harnesses related to the TP
sensor. A change in the display will indicate the
location of the fault.
Faulty AP sensor – With the ignition key “ON,” engine
“OFF,” observe the AP sensor display on the Tech 2
while slowly depressing the accelerator to wide open
throttle. If a voltage over 4.88 volts is seen at any point
in normal accelerator travel, replace the AP sensor.
If DTC P0123 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
Test Description
Number (s) below refer to the step number(s) on the
Diagnostic Chart.
8. Components that share the AP sensor 5 volt reference
“A” circuit include the following device: