Content .. 214 215 216 217 ..

Infiniti I35 (A33). Manual - part 216

DETECT MALFUNCTIONING PART

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

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 ECM terminal 80.

Refer to Wiring Diagram.

Continuity should exist.

3. Also check harness for short to power.

OK or NG

GO TO 6.

GO TO 5.

DETECT MALFUNCTIONING PART

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

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

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

GO TO 7.

Replace intake air temperature sensor.

CHECK INTERMITTENT INCIDENT

Refer to “TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT”, EC-152.

INSPECTION END

IDX

DTC P0112, P0113 IAT SENSOR

Diagnostic Procedure (Cont’d)

EC-205

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

*: This data is reference value and is 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.

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

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.

DTC P0117, P0118 ECT SENSOR

Component Description

EC-206

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-209.

WITH GST

NHEC1432S02

Follow the procedure “WITH CONSULT-II” above.

IDX

DTC P0117, P0118 ECT SENSOR

On Board Diagnosis Logic (Cont’d)

EC-207

Wiring Diagram

NHEC0860

MEC632E

DTC P0117, P0118 ECT SENSOR

Wiring Diagram

EC-208

Content .. 214 215 216 217 ..