2002 ISUZU AXIOM check engine

6E±388
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1111 IAT Sensor Circuit Intermittent High Voltage
D06RY00147
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
P1111 will set when the PCM intermittently 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 30 seconds.

Vehicle speed is less than 32 km/h (20 mph).

Engine coolant temperature is above 60
C (140
F).

Mass air flow is less than 20g/second.

IAT signal voltage indicates and intake air temperature
intermittently less than ±39
C (±38
F) (about 5 volts)
for approximately 2.5 seconds over a 25-second
period of time.
Action Taken When the DTC Sets

The PCM will substitute a default value for intake air
temperature.
The PCM will store conditions which were present
when the DTC set as Failure Records data only. This
information will not be stored as Freeze Frame data.

DTC P1111 does not illuminate the MIL.
Conditions for Clearing the MIL/DTC

A history DTC P1111 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

D T C P 1111 can be cleared by using the Tech 2 ªClear
Infoº 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
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 DTC to be set occurs. This
may assist in diagnosing the condition.

6E±390
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P1111 ±IAT Sensor Circuit Intermittent High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Is DTC P0113 also set?
Ð
Go to DTC
P0113
chart
first
Go to Step 3
3Is DTC P1115, also set?ÐGo to Step 6Go to Step 4
41. 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?
ÐVerify repairGo to Step 5
51. 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?
ÐVerify repairGo to Step 6
61. Check the IAT signal circuit between the IAT sensor
connector and the PCM for an intermittent open.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 7
71. Check the IAT signal circuit between the IAT sensor
connector and the PCM for an intermittent short to
voltage.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 8
81. Check for a poor sensor ground circuit terminal
connection at the PCM.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 9
91. 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?
ÐVerify repair
Refer to
Diagnostic
Aids

6E±391
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1112 IAT Sensor Circuit Intermittent Low Voltage
D06RY00147
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
becomes lower, causing the PCM to monitor a lower
voltage. DTC P1112 will set when the PCM intermittently
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 15 seconds.

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

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

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

The PCM will store conditions which were present
when the DTC was set as Failure Records data only.
This information will not be stored as Freeze Frame
data.

The PCM will substitute a default value for intake air
temperature.
Conditions for Clearing the MIL/DTC

A history DTC P1112 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1112 can be cleared by using the Tech 2 ªClear
Infoº 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
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 DTC to be set occurs. This
may assist in diagnosing the condition.

6E±392
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
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
ªTemperature vs. Resistance Value Chartº. The
chart may be used to test the IAT sensor at various
temperatures to evaluate the possibility of a
ªshiftedº 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
FOHMS
Temperature vs. Resistance Values
(approximate)
100212177
80176332
60140667
4511 31188
35951802
25772796
15594450
5417280
±52312300
±15521450
±30±2252700
±40±40100700
DTC P1112 ± IAT Sensor Circuit Intermittent Low Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Is DTC P0112 also set?
Ð
Go to DTC
P0112
firstGo to Step 3
31. 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?
ÐVerify repair
Refer to
Diagnostic
Aids

6E±393
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1114 ECT Sensor Circuit Intermittent Low Voltage
060R200053
Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted in the engine coolant stream. The
powertrain control module (PCM) 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 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. If the PCM detects an
ECT signal that is intermittently below the range of the
ECT sensor, DTC P1114 will set.
Conditions for Setting the DTC

Engine run time longer than 120 seconds.

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

The PCM will not illuminate the malfunction indicator
lamp (MIL).
The PCM will store conditions which were present
when the DTC set as Failure Records data only. This
information will not be stored as Freeze Frame data.
Conditions for Clearing the MIL/DTC

A history DTC P1114 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1114 can be cleared by using the Tech 2 ªClear
Infoº 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.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often

6E±394
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Engine Coolant Temperature Sensor

C
FOHMS
Temperature vs. Resistance Values
(approximate)
100212177
80176332
60140667
4511 31188
35951802
25772796
15594450
5417280
±52312300
±15521450
±30±2252700
±40±40100700
DTC P1114 ± ECT Circuit Intermittent Low Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Is DTC P0117 also set?
Ð
Go to DTC
P0117
firstGo to Step 3
31. Check the ECT signal circuit between the ECT
sensor connector and the PCM for an intermittent
short to ground.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repair
Refer to
Diagnostic
Aids

6E±395
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P1115 ECT Sensor Circuit Intermittent High Voltage
060R200053
Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted in the engine coolant stream. The
powertrain control module (PCM) 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 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. If the PCM detects an
ECT signal that is intermittently above the range of the
ECT sensor, DTC P1115 will set.
Conditions for Setting the DTC

Engine running time longer than 90 seconds.

The ECT sensor signal is intermittently greater than
±39
C (±38
F) (about 5 volts) for a total of 10 seconds
over a 100-second period.
Action Taken When the DTC Sets

The PCM will not illuminate the malfunction indicator
lamp (MIL).
The PCM will store conditions which were present
when the DTC was set as Failure Records data only.
This information will not be stored as Freeze Frame
data.
Conditions for Clearing the MIL/DTC

A history DTC P1115 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1115 can be cleared by using the Tech 2 ªClear
Infoº 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.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often

6E±397
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P1115 ± ECT Sensor Circuit Intermittent High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Is DTC P0118 also set?
Ð
Go to DTC
P0118
chart
first
Go to Step 3
3Is DTC P1111 also set?ÐGo to Step 8Go to Step 4
41. Check for a poor sensor ground circuit terminal
connection at the ECT sensor.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 5
51. Check for a poor ECT signal circuit terminal
connection at the ECT sensor.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 6
61. Check the ECT signal circuit between the ECT
sensor connector and the PCM for an intermittent
open.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 7
71. Check the ECT signal circuit between the ECT
sensor connector and the PCM for an intermittent
short to voltage.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 8
81. Check for a poor sensor ground circuit terminal
connection at the PCM.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 9
91. 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?
ÐVerify repair
Refer to
Diagnostic
Aids