1998 OPEL FRONTERA wiring

6E–118
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0112 IAT Sensor Circuit Low Voltage
D06RW026
Circuit Description
The intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The powertrain control module (PCM) 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
PCM will monitor a high signal voltage on the IAT signal
circuit. If the intake air is warm, the sensor resistance is
lower, causing the PCM to monitor a lower voltage. DTC
P0112 will set when the PCM detects an excessively low
signal voltage on the intake air temperature sensor signal
circuit.
Conditions for Setting the DTC
The engine has been running for over 2 minutes.
Vehicle speed is greater than 30 mph (48 km/h) .
IAT signal voltage indicates and intake air temperature
greater than 148C (298F) (about 5 volts) for a total
of 12.5 seconds over a 25-second period of time.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The PCM 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 PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at PCM – Inspect harness connectors
for backed-bout 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.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2. Verifies that the fault is present.

6E–121 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0113 IAT Sensor Circuit High Voltage
D06RW026
Circuit Description
The intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The powertrain control module (PCM) 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
PCM will monitor a high signal voltage on the IAT signal
circuit. If the intake air is warm, the sensor resistance is
lower causing the PCM to monitor a lower voltage. DTC
P0113 will set when the PCM detects an excessively high
signal voltage on the intake air temperature sensor signal
circuit.
Conditions for Setting the DTC
The engine has been running for over 4 minutes.
Vehicle speed is less than 20 mph (32 km/h).
ECT signal temperature is above 60C (140F).
Mass air flow is less then 20 g/second.
IAT signal voltage indicates an intake air temperature
less than –39C (–38F) for total of 12.5 seconds over
a 25-second period.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The PCM 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 PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
The IAT sensor shares a ground with the EGR position
sensor and the TP sensor. Check the ground if these
DTC’s are set.
Poor connection at PCM – 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.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2. Verifies that the fault is present.

6E–124
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0117 ECT Sensor Circuit Low Voltage
060RY00304
Circuit Description
The engine coolant temperature (ETC) sensor is a
thermistor mounted on a coolant crossover pipe at the
rear of the engine. The powertrain control module (PCM)
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
PCM will measure a high signal voltage. As the engine
coolant warms, the sensor resistance becomes lower,
and the ECT signal voltage measured at the PCM drops.
With a fully warmed-up engine, the ECT signal voltage
should measure about 1.5 to 2.0 volts.
Conditions for Setting the DTC
Engine running time is longer than one minute.
The ECT sensor signal indicates an engine coolant
temperature greater than 150C (302F) (about 0.10
V) for a total of 50 seconds over a 100–second period.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The PCM will substitute the ECT reading with a default
engine coolant temperature value. The default value
is based on start-up intake air temperature and running
time.
The PCM 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 PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at PCM – 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 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.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.

6E–127 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0118 ECT Sensor Circuit High Voltage
060RY00304
Circuit Description
The engine coolant temperature (ETC) sensor is a
thermistor mounted in on a coolant crossover pipe at the
rear of the engine. The powertrain control module (PCM)
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
PCM will measure a high signal voltage. As the engine
coolant warms, the sensor resistance becomes less, and
the ECT signal voltage measured at the PCM drops. With
a fully warmed-up engine, the ECT signal voltage should
measure about 1.5 to 2.0 volts.
Conditions for Setting the DTC
Engine running time is longer than 1.5 minutes.
The ECT sensor signal indicates an engine coolant
temperature of –39C (–38F) or less (about 5 volts)
for a total of 50 seconds over a 100-second period.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The PCM will substitute the ECT reading with a default
engine coolant temperature value. The default value
is based on start-up intake air temperature and running
time.
The PCM 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 PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
The ECT shares a ground with the Transmission Fluid
Temperature sensor, the Rough Road sensor, and the
MAP sensor.
Check the ground if these DTCs are also set.
Poor connection at PCM – 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.
If it is determined that the DTC occurs intermittently,
performing the DTC P1115 Diagnostic Chart may isolate
the cause of the fault.

6E–130
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0121 TP System Performance
D06RW028
Circuit Description
The throttle position (TP) sensor circuit provides a voltage
signal that changes relative to throttle blade angle. The
signal voltage will vary from about 0.6 volts at closed
throttle to about 4.5 volts at wide open throttle (WOT).
The TP signal is used by the powertrain control module
(PCM) for fuel control and many of the PCM-controlled
outputs. The PCM monitors throttle position and
compares actual throttle position from the TP sensor to a
predicted TP value calculated from engine speed. If the
PCM detects an out-of-range condition, DTC P0121 will
set.
Conditions for Setting the DTC
The engine is running.
No MAP DTCs, or P0121, P0122, P0123 are set.
MAP reading is below 55 kPa.
Throttle is steady, throttle angle is changing less than
1%.
Predicted throttle angle is not close to actual throttle
angle.
Above conditions are present for a total of 12.5
seconds over a 25-second period of time.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
The PCM will use a default throttle position based on
mass air flow and RPM.
Conditions for Clearing the MIL/DTC
DTC P0121 can be cleared by using the Tech 2 “Clear
info ” function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
Skewed MAP signal or faulty Map sensor – An
incorrect MAP signal may cause the PCM to incorrectly
calculate the predicted TP sensor value during high
engine load situations. Check for an unusually low
MAP reading. This condition can cause DTC P0121 to
be set.
Poor connection at PCM – 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–131 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0121 –TP System Performance
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
21. Ignition “ON,” engine not running.
2. Observe the MAP reading on the Tech 2.
Is the MAP reading less than the specified value?
65 kPaGo to Step 3Go to Step 6
31. Disconnected the MAP sensor.
2. Connect a test light between the 5 volt reference “A”
circuit and the MAP signal circuit at the MAP sensor
harness connector.
3. Observe the MAP reading on the Tech 2.
Is the MAP reading less than the specified value?
65 kPaGo to Step 5Go to Step 4
41. Check the MAP signal circuit between the PCM and
the MAP sensor for an open, short to ground, or
short to the MAP ground circuit.
2. If the MAP signal circuit is open or shorted, repair it
as necessary.
Was the MAP signal circuit open or shorted?
—Verify repairGo to Step 12
5Replace the MAP sensor.
Is the action complete?
—Verify repair—
6Observe the TP angle reading on the Tech 2 while
slowly opening the throttle.
Does the TP angle increase steadily and evenly from
the closed throttle value to the wide open throttle
value?Closed
throttle = 0%
Wide open
throttle =
100%
Refer to
Diagnostic
Aids
Go to Step 7
71. Disconnect the TP sensor.
2. Observe the TP sensor reading on the Tech 2.
Is the TP sensor reading near the specified value?
0 VGo to Step 8Go to Step 9
81. Connect a test light between the 5 volt reference “A”
circuit and the TP sensor signal circuit at the TP
sensor harness connector.
2. Observe the TP sensor reading on the Tech 2.
Is the TP sensor reading at the specified value?
5 VGo to Step 11Go to Step 10
9Check the following items:
1. TP signal circuit for a short to voltage.
2. TP sensor ground circuit for high resistance
between the PCM and the TP sensor.
3. TP sensor ground circuit for a poor connection.
4. If a problem is found, repair wiring harness as
necessary.
Was a problem found?
—Verify repairGo to Step 12

6E–132
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0121 –TP System Performance
StepNo Ye s Va l u e ( s ) Action
10Check the following items:
1. TP signal circuit or 5 volt reference “A” circuit for a
poor connection.
2. TP signal circuit or 5 volt reference “A” circuit for
high resistance between the PCM and the TP
sensor.
3. If a problem is found, repair wiring harness as
necessary.
Was a problem found?
—Verify repairGo to Step 12
11Replace the TP sensor.
Is the action complete?
—Verify repair—
12Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—

6E–133 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0122 TP Sensor Circuit Low Voltage
D06RW028
Circuit Description
The throttle position (TP) sensor circuit provides a voltage
signal that changes relative to throttle blade angle. The
signal voltage will vary from below 0.6 volts at closed
throttle to about 4.5 volts at wide open throttle (WOT).
The TP signal is used by the powertrain control module
(PCM) for fuel control and many of the PCM–controlled
outputs.
Conditions for Setting the DTC
The ignition is “ON.”
TP sensor signal voltage is less than 0.22 volt for a total
of 0.78 second over a 1.5-second period.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
The PCM will use a default throttle position based on
mass air flow and RPM.
Conditions for Clearing the MIL/DTC
DTC P0122 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
Check intermittent codes.
The TP sensor shares a 5 Volt reference with the EGR
position sensor. Check the 5 Volt reference if these
DTCs are also set.
The TP sensor shares a ground with the IAT sensor,
the EGR position sensor.
Poor connection at PCM – 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.