Opel Frontera UE. Manual - part 228

6E1–210

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P1111 – IAT Sensor Circuit Intermittent High Voltage

 

Step

Action

Value(s)

Yes

No

1

Was the ”On–Board Diagnostic (OBD) System Check”
performed?

—

Go to Step  2 

Go to OBD

System

Check 

2

Is DTC P0113 also set?

—

Go to DTC

P0113 chart

first 

Go to Step 3 

3

1. Check for a poor sensor ground circuit terminal

connection at the IAT sensor.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to Step 4 

4

1. Check for a poor IAT signal circuit terminal

connection at the IAT sensor.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to Step 5 

5

1. Check the IAT signal circuit between the IAT sensor

connector and the ECM for an intermittent open.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to Step 6 

6

1. Check the IAT signal circuit between the IAT sensor

connector and the ECM for an intermittent short to
voltage.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to Step 7 

7

1. Check for a poor sensor ground circuit terminal

connection at the ECM.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to Step 8 

8

1. Check for an intermittent open or a faulty splice in

the sensor ground circuit.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Refer to

Diagnostic

Aids 

6E1–211

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P1112 INTAKE AIR TEMPERATURE (IAT)

SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE

D06RX117

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
becomes lower, causing the ECM to monitor a lower
voltage. Diagnostic Trouble Code P1112 will set when the
ECM intermittently detects an excessively low signal
voltage on the intake air temperature sensor signal
circuit.  DTC P1112 is a type D code.

Conditions for Setting the DTC

D

The engine has been running for over 2 minutes.

D

Vehicle speed is greater than 48 km/h (30 mph).

D

IAT signal voltage is greater than 148

°

C (298

°

F)

(about 0.10 volt) for a total of 2.5 seconds over a
25–second period of time.

Action Taken When the DTC Sets

D

The ECM will not illuminate the malfunction indicator
lamp (MIL).

D

The ECM will store conditions which were present
when the Diagnostic Trouble Code set as Failure

Records data only. This information will not be stored
as Freeze Frame data.

D

The ECM will substitute a default value for intake air
temperature.

Conditions for Clearing the DTC

D

A history Diagnostic Trouble Code P1112 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.

D

Diagnostic Trouble Code P1112 can be cleared by
using the Scan Tool’s ”Clear Info” function.

Diagnostic Aids

Check for the following conditions:

D

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.

D

Damaged harness – Inspect the wiring harness for
damage; shorts to ground, shorts to battery positive,
and open circuits. 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.

Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the Diagnostic Trouble Code to

6E1–212

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

be set occurs. This may assist in diagnosing the
condition.

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 P1112 can be repeated only by duplicating

the Failure Records conditions, refer to the
”Temperature vs. Resistance Value Chart.” 

The chart may be used to test the IAT 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 IAT sensor.

Intake Air Temperature Sensor

°

C

°

F

W

Temperature vs. Resistance Values (approximate)

100

212

177

80

176

332

60

140

667

45

113

1188

35

95

1802

25

77

2796

15

59

4450

5

41

7280

–5

23

12300

–15

5

21450

–30

–22

52700

–40

–40

100700

DTC P1112 – IAT Sensor Circuit Intermittent Low Voltage

 

Step

Action

Value(s)

Yes

No

1

Was the ”On–Board Diagnostic (OBD) System Check”
performed?

—

Go to Step  2 

Go to OBD

System

Check 

2

Is DTC P0112 also set?

—

Go to DTC

P0112 chart

first 

Go to Step  3 

3

1. Check the IAT signal circuit between the IAT sensor

connector and the PCM for an intermittent short to
ground.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Refer to

Diagnostic

Aids 

6E1–213

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P1114 ENGINE COOLANT

TEMPERATURE (ECT) SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE

D06RX117

Circuit Description

The engine coolant temperature (ECT) sensor is a
thermistor mounted in the engine coolant stream. The
engine control module (ECM) applies a voltage (about 5.0
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. With a fully warmed up
engine, the ECT signal voltage should measure about 1.5
to 2.0 volts. If the ECM detects an ECT signal that is
intermittently below the range of the ECT sensor,
Diagnostic Trouble Code P1114 will set. DTC P1114 is a
type D code.

Conditions for Setting the DTC

D

Engine run time longer than 2 minutes.

D

The ECT sensor signal is intermittently greater than
150

°

C (302

°

F) (about 0.10 volt) for a total of 10

seconds over a 100–second period.

Action Taken When the DTC Sets

D

The ECM will not illuminate the malfunction indicator
lamp (MIL).

D

The ECM will store conditions which were present
when the Diagnostic Trouble Code set as Failure

Records data only. This information will not be stored
as Freeze Frame data.

Conditions for Clearing the DTC

D

A history Diagnostic Trouble Code P1114 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.

D

Diagnostic Trouble Code P1114 can be cleared by
using the Scan Tool’s ”Clear Info” function.

Diagnostic Aids

Check for the following conditions:

D

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.

D

Damaged harness – Inspect the wiring harness for
damage; shorts to ground, shorts to battery positive,
and open circuits. 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.

Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the Diagnostic Trouble Code to
be set occurs. This may assist in diagnosing the
condition.