Infiniti M35/M45 Y50. Manual - part 613

DTC P0112, P0113 IAT SENSOR

EC-925

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3. 

CHECK INTAKE AIR TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check harness continuity between mass air flow sensor terminal 6 and ECM terminal 67.
Refer to Wiring Diagram.

4.

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

OK or NG

OK

>> GO TO 4.

NG

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

4. 

CHECK INTAKE AIR TEMPERATURE SENSOR

Refer to 

EC-925, "Component Inspection"

 .

OK or NG

OK

>> GO TO 5.

NG

>> Replace mass air flow sensor (with intake air temperature sensor).

5. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-857, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

NBS005CR

INTAKE AIR TEMPERATURE SENSOR

1.

Check resistance between mass air flow sensor (1) terminals 5
and 6 under the following conditions.

2.

If NG, replace mass air flow sensor (with intake air temperature
sensor).

Removal and Installation

NBS005CS

MASS AIR FLOW SENSOR

Refer to 

EM-177, "AIR CLEANER AND AIR DUCT"

 .

Continuity should exist.

Intake air temperature 

°

C (

°

F)

Resistance k

Ω

25 (77)

1.800 - 2.200

PBIA9559J

SEF012P

EC-926

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DTC P0117, P0118 ECT SENSOR

DTC P0117, P0118 ECT SENSOR

PFP:22630

Component Description

NBS005CT

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 ther-
mistor decreases as temperature increases.

<Reference data>

*: This data is reference value and is measured between ECM terminal 73 (Engine
coolant temperature sensor) and ground.

CAUTION:

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

On Board Diagnosis Logic

NBS005CU

These self-diagnoses have the one trip detection logic.

FAIL-SAFE MODE

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

SEF594K

Engine coolant temperature

°

C (

°

F)

Voltage*

V

Resistance

k

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

SEF012P

DTC No.

Trouble Diagnosis Name

DTC Detecting Condition

Possible Cause

P0117
0117

Engine coolant temperature 
sensor circuit 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 temperature 
sensor circuit high input

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

Detected items

Engine operating condition in fail-safe mode

Engine coolant temperature 
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.

DTC P0117, P0118 ECT SENSOR

EC-927

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DTC Confirmation Procedure

NBS005CV

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

1.

Turn ignition switch ON.

2.

Select “DATA MONITOR” mode with CONSULT-II.

3.

Wait at least 5 seconds.

4.

If DTC is detected, go to 

EC-929, "Diagnostic Procedure"

 .

 WITH GST

Follow the procedure “WITH CONSULT-II” above.

SEF058Y

EC-928

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DTC P0117, P0118 ECT SENSOR

Wiring Diagram

NBS005CW

TBWT1018E