Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 842

6E–97

3.2L 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 P0113 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 IAT sensor at various
temperatures to evaluate the possibility of a
“shifted” sensor that may be open above or below a
certain temperature. If this is the case, replace the
IAT sensor. If the IAT sensor appears to be OK, the
fault is intermittent; refer to

Diagnostic Aids.

Intake Air Temperature Sensor

OHMS

Temperature vs. Resistance Values

(approximate)

100

212

177

176

332

140

667

113

1188

1802

2796

4450

7280

–5

12300

–15

21450

–30

–22

52700

–40

100700

DTC P0113 –IAT Sensor Circuit High Voltage

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

Ignition “ON,” engine “OFF.” Observe the “Intake Air
Temp” display on the Tech 2.

Is the “Intake Air Temp” below the specified value?

–38

(–36

Go to

Step 4

Go to

Step 3

1. Ignition “ON,” engine “OFF.”
2. Review and record Tech 2 Failure Records data

parameters.

3. Operate the vehicle within Failure Records

conditions as noted.

4. Using a Tech 2, monitor “ DTC” info for DTC P0113.

Does the Tech 2 indicate DTC P0113 failed?

—

Refer to

Test

Description

Refer to

Diagnostic

Aids

1. Ignition “OFF.”
2. Disconnect the IAT sensor electrical connector.
3. Jumper the IAT signal circuit and the sensor ground

circuit together at the IAT sensor harness
connector.

4. Ignition “ON.”
5. Observe the “Intake Air Temp” display on the Tech

Is the “Intake Air Temp” at the specified value?

140

(284

Go to

Step 6

Go to

Step 5

1. Jumper the IAT signal circuit at the IAT sensor

harness connector to chassis ground.

2. Observe the “Intake Air Temp” display on the Tech

Is the “Intake Air Temp” at the specified value?

140

(284

Go to

Step 7

Go to

Step 8

6E–98

3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0113 –IAT Sensor Circuit High Voltage

(Cont'd)

Step

Yes

Value(s)

Action

Check for poor connections at the IAT sensor and
replace terminals if necessary.

Did any terminals require replacement?

—

Verify repair

Go to

Step 10

1. Ignition “OFF.”
2. Disconnect the ECM, and check the IAT sensor

ground circuit for an open.

3. If the IAT sensor ground circuit is open, repair it as

necessary.

Was the IAT sensor ground circuit open?

—

Verify repair

Go to

Step 9

1. Ignition “OFF.”
2. Disconnect the ECM, and check the IAT signal

circuit for an open.

3. If the IAT sensor signal circuit is open, repair it as

necessary.

Was the IAT signal circuit open?

—

Verify repair

Go to

Step 9

Check for a poor sensor ground or IAT signal circuit
terminal connection at the ECM and replace
terminal(s) if necessary.

Did any of the terminals need to be replaced?

—

Verify repair

Go to

Step 11

Replace the IAT sensor.

Is the action complete?

—

Verify repair

—

Replace the ECM.

Is the action complete?

—

Verify repair

—

6E–99

3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0117 (Flash DTC=14) ECT Sensor Circuit Low

Voltage

060RW072

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.
With a fully warmed-up engine, the ECT signal voltage
should measure about 1.5 to 2.0 volts.

Conditions for Setting the DTC

Ignition SW is ON.

The ECT sensor voltage is under 80m volts.

Above conditions present for at least 5 second.

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 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 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

The ECM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0117 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

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, 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.
If it is determined that the DTC occurs intermittently.

6E–100 3.2L 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 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.

Engine Coolant Temperature Sensor

OHMS

Temperature vs. Resistance Values

(approximate)

100

212

177

176

332

140

667

113

1188

1802

2796

4450

7280

–5

12300

–15

21450

–30

–22

52700

–40

100700

DTC P0117 – ECT Sensor Low Voltage

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

1. Ignition “ON,” engine “OFF.”
2. Observe the “Eng Cool Temp” display on the Tech 2.

Is the “Eng Cool Temp” below the specified value?

139

(282

Go to

Step 4

Go to

Step 3

1. Ignition “ON,” engine “OFF.”
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records

conditions as noted.

4. Using a Tech 2, monitor “ DTC” info for DTC P0117.

Does the Tech 2 indicate DTC P0117 failed this
ignition?

—

Go to

Step 4

Refer to

Diagnostic

Aids

1. Disconnect the ECT sensor electrical connector.
2. Observe the “Eng Cool Temp” display on the Tech 2.

Is the “Eng Cool Temp” at the specified value?

–39

(–38

Go to

Step 6

Go to

Step 5

1. Ignition “OFF.”
2. Disconnect the ECM and check the ECT signal

circuit for a short to ground or a short to the sensor
ground circuit.

3. If the ECT signal circuit is shorted. repair it as

necessary.

Was the ECT signal circuit shorted to ground?

—

Verify repair

Go to

Step 7

Replace the ECT sensor.

Is the action complete?

—

Verify repair

—

Replace the ECM.

Is the action complete?

—

Verify repair

—

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