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Infiniti I30. Emission Control System (2003 year). Manual - part 13

Wiring Diagram

NHEC0753

MEC531D

SEF650XE

IDX

DTC P0102, P0103 MAF SENSOR

Wiring Diagram

EC-193

Diagnostic Procedure

NHEC0754

INSPECTION START

Which malfunction (P0102 or P0103) is duplicated?

P0102 or P0103

P0103

䊳

GO TO 3.

P0102

䊳

GO TO 2.

CHECK INTAKE SYSTEM

Check the following for connection.

쐌

Air duct

쐌

Vacuum hoses

쐌

Intake air passage between air duct to intake manifold collector

OK or NG

䊳

GO TO 3.

䊳

Reconnect the parts.

RETIGHTEN GROUND SCREWS

1. Turn ignition switch “OFF”.
2. Loosen and retighten engine ground screws.

SEC047D

䊳

GO TO 4.

DTC P0102, P0103 MAF SENSOR

Diagnostic Procedure

EC-194

CHECK MAF SENSOR POWER SUPPLY CIRCUIT

1. Disconnect mass air flow (MAF) sensor harness connector.

SEC055D

2. Turn ignition switch “ON”.
3. Check voltage between MAF sensor terminals 2, 4 and ground with CONSULT-II or tester.

SEF297X

OK or NG

䊳

GO TO 6.

䊳

GO TO 5.

DETECT MALFUNCTIONING PART

Check the following.

쐌

Harness connectors E15, F18

쐌

Harness for open or short between ECM relay and mass air flow sensor

쐌

Harness for open or short between mass air flow sensor and ECM

䊳

Repair harness or connectors.

CHECK MAF SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch “OFF”.
2. Disconnect ECM harness connector.
3. Check harness continuity between MAF sensor terminal 3 and ECM terminal 80.

Refer to Wiring Diagram.

Continuity should exist.

4. Also check harness for short to power.

OK or NG

䊳

GO TO 7.

䊳

Repair open circuit or short to power in harness or connectors.

IDX

DTC P0102, P0103 MAF SENSOR

Diagnostic Procedure (Cont’d)

EC-195

CHECK MAF SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Check harness continuity between MAF sensor terminal 1 and ECM terminal 62.

Refer to Wiring Diagram.

Continuity should exist.

2. Also check harness for short to ground and short to power.

OK or NG

䊳

GO TO 8.

䊳

Repair open circuit or short to ground or short to power in harness or connectors.

CHECK MASS AIR FLOW SENSOR

1. Reconnect harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal 62 (Mass air flow sensor signal) and ground.

SEC103D

4. If the voltage is out of specification, disconnect MAF sensor harness connector and connect it again.

Then repeat above check.

OK or NG

䊳

GO TO 9.

䊳

Replace mass air flow sensor.

CHECK INTERMITTENT INCIDENT

Refer to “TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT”, EC-151.

䊳

INSPECTION END

DTC P0102, P0103 MAF SENSOR

Diagnostic Procedure (Cont’d)

EC-196

Component Description

NHEC0848

The absolute pressure sensor is built into ECM. The sensor detects
ambient barometric pressure and sends the voltage signal to the
microcomputer.

On Board Diagnosis Logic

NHEC0849

DTC No.

Trouble diagnosis

name

DTC Detecting Condition

Possible Cause

P0107
0107

Absolute pressure
sensor circuit low
input

An excessively low voltage from the sensor is sent
to ECM.

쐌

Absolute pressure sensor

쐌

ECM

P0108
0108

Absolute pressure
sensor circuit high
input

An excessively high voltage from the sensor is
sent to ECM.

DTC Confirmation Procedure

NHEC0850

NOTE:
If “DTC Confirmation Procedure” has been previously conducted,
always turn ignition switch OFF and wait at least 10 seconds before
conducting the next test.

SEF058Y

With CONSULT-II

Turn ignition switch ON.

Select “DATA MONITOR” mode with CONSULT-II.

Wait at least 6 seconds.

If 1st trip DTC is detected, go to “Diagnostic Procedure”,
EC-198.

With GST

Follow the procedure “With CONSULT-II”.

IDX

DTC P0107, P0108 ABSOLUTE PRESSURE SENSOR

Component Description

EC-197

Diagnostic Procedure

NHEC0851

INSPECTION START

With CONSULT-II

1. Turn ignition switch ON.
2. Select “SELF DIAG RESULTS” mode with CONSULT-II.
3. Touch “ERASE”.
4. Perform “DTC Confirmation Procedure”.

See EC-197.

5. Is the 1st trip DTC P0107 or P0108 displayed again?

With GST

1. Turn ignition switch ON.
2. Select MODE 4 with GST.
3. Touch “ERASE”.
4. Perform “DTC Confirmation Procedure”.

See EC-197.

5. Is the 1st trip DTC P0107 or P0108 displayed again?

Yes or No

Yes

䊳

GO TO 2.

䊳

INSPECTION END

REPLACE ECM

1. Replace ECM.
2. Perform initialization of IVIS (NATS) system and registration of all IVIS (NATS) ignition key IDs. Refer to “IVIS (INFINITI

VEHICLE IMMOBILIZER SYSTEM — NATS)”, EC-90.

3. Perform “Accelerator Pedal Released Position Learning”, EC-71.
4. Perform “Throttle Valve Closed Position Learning”, EC-71.
5. Perform “Idle Air Volume Learning”, EC-71.

䊳

INSPECTION END

DTC P0107, P0108 ABSOLUTE PRESSURE SENSOR

Diagnostic Procedure

EC-198

SEC266C

SEF012P

Component Description

NHEC0852

The intake air temperature sensor is mounted to the air duct hous-
ing. The sensor detects intake air temperature and transmits a sig-
nal to the ECM.
The temperature sensing unit uses a thermistor which is sensitive
to the change in temperature. Electrical resistance of the thermistor
decreases in response to the temperature rise.
<Reference data>

Intake air

temperature

°C (°F)

Voltage*

Resistance

Ω

25 (77)

3.32

1.9 - 2.1

*: These data are reference values and are measured between ECM terminal 66
(Intake air temperature sensor) and body ground.

CAUTION:

Do not use ECM ground terminals when measuring input/
output voltage. Doing so may result in damage to the ECM’s
transistor. Use a ground other than ECM terminals, such as
the ground.

On Board Diagnosis Logic

NHEC0853

DTC No.

Trouble diagnosis

name

DTC Detecting Condition

Possible Cause

P0112
0112

Intake air temperature
sensor circuit low
input

An excessively low voltage from the sensor is sent
to ECM.

쐌

Harness or connectors
(The sensor circuit is open or
shorted.)

쐌

Intake air temperature sensor

P0113
0113

Intake air temperature
sensor circuit high
input

An excessively high voltage from the sensor is
sent to ECM.

DTC Confirmation Procedure

NHEC0854

NOTE:
If “DTC Confirmation Procedure” has been previously conducted,
always turn ignition switch “OFF” and wait at least 10 seconds
before conducting the next test.

SEF058Y

WITH CONSULT-II

NHEC0854S01

Turn ignition switch “ON”.

Select “DATA MONITOR” mode with CONSULT-II.

Wait at least 5 seconds.

If 1st trip DTC is detected, go to “Diagnostic Procedure”,
EC-201.

WITH GST

NHEC0854S02

Follow the procedure “With CONSULT-II” above.

IDX

DTC P0112, P0113 IAT SENSOR

Component Description

EC-199

Wiring Diagram

NHEC0855

MEC532D

DTC P0112, P0113 IAT SENSOR

Wiring Diagram

EC-200

Diagnostic Procedure

NHEC0856

CHECK INTAKE AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT

1. Turn ignition switch “OFF”.
2. Disconnect intake air temperature sensor harness connector.

SEC055D

3. Turn ignition switch “ON”.
4. Check voltage between terminal 5 and ground.

SEC104D

OK or NG

䊳

GO TO 3.

䊳

GO TO 2.

DETECT MALFUNCTIONING PART

Check harness for open or short between ECM and intake air temperature sensor.

䊳

Repair harness or connectors.

CHECK INTAKE AIR TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch “OFF”.
2. Check harness continuity between sensor terminal 3 and engine ground.

Refer to Wiring Diagram.

Continuity should exist.

3. Also check harness for short to power.

OK or NG

䊳

GO TO 5.

䊳

GO TO 4.

DETECT MALFUNCTIONING PART

Check harness for open between ECM and intake air temperature sensor.

䊳

Repair open circuit or short to power in harness or connectors.

IDX

DTC P0112, P0113 IAT SENSOR

Diagnostic Procedure

EC-201

CHECK INTAKE AIR TEMPERATURE SENSOR

Check resistance between intake air temperature sensor terminals 3 and 5 as shown in the figure.

MTBL1143

SEF012P

OK or NG

䊳

GO TO 6.

䊳

Replace intake air temperature sensor.

CHECK INTERMITTENT INCIDENT

Refer to “TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT”, EC-151.

䊳

INSPECTION END

DTC P0112, P0113 IAT SENSOR

Diagnostic Procedure (Cont’d)

EC-202

SEF594K

Component Description

NHEC0857

The engine coolant temperature sensor is used to detect the
engine coolant temperature. The sensor modifies a voltage signal
from the ECM. The modified signal returns to the ECM as the
engine coolant temperature input. The sensor uses a thermistor
which is sensitive to the change in temperature. The electrical
resistance of the thermistor decreases as temperature increases.

SEF012P

<Reference data>

Engine coolant

temperature

°C (°F)

Voltage*

Resistance

Ω

−10 (14)

4.4

7.0 - 11.4

20 (68)

3.5

2.1 - 2.9

50 (122)

2.2

0.68 - 1.00

90 (194)

0.9

0.236 - 0.260

*: These data are reference values and are measured between ECM terminal 93
(Engine coolant temperature sensor) and ground.

CAUTION:

Do not use ECM ground terminals when measuring input/
output voltage. Doing so may result in damage to the ECM’s
transistor. Use a ground other than ECM terminals, such as
the ground.

On Board Diagnosis Logic

NHEC1431

These self-diagnoses have the one trip detection logic.

DTC No.

Trouble diagnosis

name

DTC Detecting Condition

Possible Cause

P0117
0117

Engine coolant tem-
perature sensor cir-
cuit low input

An excessively low voltage from the sensor is sent
to ECM.

쐌

Harness or connectors
(The sensor circuit is open or
shorted.)

쐌

Engine coolant temperature sensor

P0118
0118

Engine coolant tem-
perature sensor cir-
cuit high input

An excessively high voltage from the sensor is
sent to ECM.

FAIL-SAFE MODE

NHEC1431S01

When this malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.

IDX

DTC P0117, P0118 ECT SENSOR

Component Description

EC-203

Detected items

Engine operating condition in fail-safe mode

Engine coolant tem-

perature sensor circuit

Engine coolant temperature will be determined by ECM based on the time after turning ignition switch
“ON” or “START”.
CONSULT-II displays the engine coolant temperature decided by ECM.

Condition

Engine coolant temperature decided (CONSULT-II

display)

Just as ignition switch is turned ON or Start

40°C (104°F)

More than approx. 4 minutes after ignition ON or
Start

80°C (176°F)

Except as shown above

40 - 80°C (104 - 176°F)

(Depends on the time)

When the fail-safe system for engine coolant temperature sensor is activated, the cooling fan operates
while engine is running.

SEF058Y

DTC Confirmation Procedure

NHEC1432

NOTE:
If “DTC Confirmation Procedure” has been previously conducted,
always turn ignition switch “OFF” and wait at least 10 seconds
before conducting the next test.

WITH CONSULT-II

NHEC1432S01

Turn ignition switch “ON”.

Select “DATA MONITOR” mode with CONSULT-II.

Wait at least 5 seconds.

If DTC is detected, go to “Diagnostic Procedure”, EC-206.

WITH GST

NHEC1432S02

Follow the procedure “WITH CONSULT-II” above.

DTC P0117, P0118 ECT SENSOR

On Board Diagnosis Logic (Cont’d)

EC-204

Wiring Diagram

NHEC0860

MEC349E

IDX

DTC P0117, P0118 ECT SENSOR

Wiring Diagram

EC-205

Diagnostic Procedure

NHEC0861

CHECK ECT SENSOR POWER SUPPLY CIRCUIT

1. Turn ignition switch “OFF”.
2. Disconnect engine coolant temperature (ECT) sensor harness connector.

SEC105D

3. Turn ignition switch “ON”.
4. Check voltage between ECT sensor harness connector terminal 1 and ground with CONSULT-II or tester.

SEC106D

OK or NG

䊳

GO TO 3.

䊳

GO TO 2.

DETECT MALFUNCTIONING PART

Check harness for open or short between ECM and engine coolant temperature sensor.

䊳

Repair harness or connectors.

CHECK ECT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch “OFF”.
2. Check harness continuity between ECT sensor terminal 2 and engine ground.

Refer to Wiring Diagram.

Continuity should exist.

3. Also check harness for short to power.

OK or NG

䊳

GO TO 5.

䊳

GO TO 4.

DTC P0117, P0118 ECT SENSOR

Diagnostic Procedure

EC-206

DETECT MALFUNCTIONING PART

Check the following.

쐌

Joint connector-20

쐌

Harness for open between ECM and engine coolant temperature sensor

쐌

Harness for open between TCM (Transmission Control Module) and engine coolant temperature sensor

䊳

Repair open circuit or short to power in harness or connectors.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

Check resistance between engine coolant temperature sensor terminals 1 and 2 as shown in the figure.

SEF304X

OK or NG

䊳

GO TO 6.

䊳

Replace engine coolant temperature sensor.

CHECK INTERMITTENT INCIDENT

Refer to “TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT”, EC-151.

䊳

INSPECTION END

IDX

DTC P0117, P0118 ECT SENSOR

Diagnostic Procedure (Cont’d)

EC-207

PBIB0145E

Component Description

NHEC1333

Electric throttle control actuator consists of throttle control motor,
throttle position sensor, etc. The throttle position sensor responds
to the throttle valve movement.
The throttle position sensor has the two sensors. These sensors
are a kind of potentiometers which transform the throttle valve
position into output voltage, and emit the voltage signal to the ECM.
In addition, these sensors detect the opening and closing speed of
the throttle valve and feed the voltage signals to the ECM. The
ECM judges the current opening angle of the throttle valve from
these signals and the ECM controls the throttle control motor to
make the throttle valve opening angle properly in response to driv-
ing condition.

CONSULT-II Reference Value in Data Monitor
Mode

NHEC1334

Specification data are reference values.

MONITOR ITEM

CONDITION

SPECIFICATION

THRTL SEN2*

쐌

Ignition switch:
ON (Engine stopped)

쐌

Shift lever: D

Accelerator pedal: Released

More than 0.36V

Accelerator pedal: Fully depressed

Less than 4.75V

*: Throttle position sensor 2 signal is converted by ECM internally. Thus, it differs from ECM terminal voltage signal.

On Board Diagnosis Logic

NHEC1455

These self-diagnoses have the one trip detection logic.

DTC No.

Trouble diagnosis

name

DTC Detecting Condition

Possible Cause

P0122
0122

Throttle position sen-
sor 2 circuit low input

An excessively low voltage from the TP sensor 2
is sent to ECM.

쐌

Harness or connectors
(The TP sensor 2 circuit is open or
shorted.)

쐌

Electric throttle control actuator (TP
sensor 2)

P0123
0123

Throttle position sen-
sor 2 circuit high
input

An excessively high voltage from the TP sensor 2
is sent to ECM.

FAIL-SAFE MODE

NHEC1455S01

When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.

Engine operation condition in fail-safe mode

The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within
+10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal condition.
So, the acceleration will be poor.

DTC P0122, P0123 TP SENSOR

Component Description

EC-208

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