Nissan Quest E52. Instruction — part 498

EC-202

< DTC/CIRCUIT DIAGNOSIS >

[VQ35DE]

P0127 IAT SENSOR

Component Inspection

INFOID:0000000009651062

1.

CHECK INTAKE AIR TEMPERATURE SENSOR

1.

Turn ignition switch OFF.

2.

Disconnect mass air flow sensor harness connector.

3.

Check resistance between mass air flow sensor terminals as follows.

Is the inspection result normal?

YES

>> INSPECTION END

NO

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

EM-26, "Exploded

View"

.

Terminals

Condition

Resistance (k

Ω

)

1 and 2

Temperature [

°

C (

°

F)]

25 (77)

1.800 - 2.200

P0128 THERMOSTAT FUNCTION

EC-203

< DTC/CIRCUIT DIAGNOSIS >

[VQ35DE]

C

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EC

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P0128 THERMOSTAT FUNCTION

DTC Logic

INFOID:0000000009651063

DTC DETECTION LOGIC

NOTE:
If DTC P0128 is displayed with DTC P0300, P0301, P0302, P0303, P0304, P0305 or P0306, first perform
the trouble diagnosis for P0300, P0301, P0302, P0303, P0304, P0305, P0306. Refer to

EC-263, "DTC

Logic"

.

Engine coolant temperature has not risen enough to open the thermostat even though the engine has run long
enough.
This is due to a leak in the seal or the thermostat being stuck open.

DTC CONFIRMATION PROCEDURE

NOTE:
Never refuel before and during the following procedure.

1.

PRECONDITIONING-I

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next test.
1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON.

3.

Turn ignition switch OFF and wait at least 10 seconds.

>> GO TO 2.

2.

PRECONDITIONING-II

With CONSULT

1.

Turn ignition switch ON.

2.

Check the following conditions:

3.

Select “DATA MONITOR” mode of “ENGINE” using CONSULT.

4.

Check the following conditions:

Is the condition satisfied?

YES

>> GO TO 3.

NO

>> 1.

Satisfy the condition.

2.

GO TO 3.

3.

PERFORM DTC CONFIRMATION PROCEDURE-I

With CONSULT

1.

Start engine.

2.

Drive the vehicle until the following condition is satisfied.

CAUTION:

Always drive vehicle at safe speed.

-

STEP 1

DTC No.

Trouble diagnosis

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P0128

THERMSTAT FNCTN
[Coolant thermostat (coolant
temperature below thermostat
regulating temperature)]

The engine coolant temperature does not
reach to specified temperature even though
the engine has run long enough.

• Thermostat
• Leakage from sealing portion of ther-

mostat

• Engine coolant temperature sensor

Ambient temperature

−

10

°

C (14

°

F) or more

A/C switch

OFF

Blower fan switch

OFF

COOLAN TEMP/S

−

10

°

C – 46

°

C (14 – 115

°

F)

EC-204

< DTC/CIRCUIT DIAGNOSIS >

[VQ35DE]

P0128 THERMOSTAT FUNCTION

Drive the vehicle under the conditions instructed below until the difference between “COOLAN TEMP/S” and

“FUEL T/TMP SE” becomes at least 24

°

C (43

°

F).

*: Example

-

STEP 2

Drive the vehicle at 50 km/h (32 MPH) or more with the difference between “COOLAN TEMP/S” and “FUEL

T/TMP SE” maintained at 24

°

C (43

°

F) or more.

NOTE:
Keep the accelerator pedal as steady as possible during cruising.

-

STEP 3

Drive the vehicle at 50 km/h (32 MPH) or more until “COOLAN TEMP/S” increases by 6

°

C (11

°

F).

NOTE:
Keep the accelerator pedal as steady as possible during cruising.

Is the condition satisfied?

YES

>> GO TO 4.

NO

>> GO TO 1.

4.

PERFORM DTC CONFIRMATION PROCEDURE-II

With CONSULT

1.

Drive the vehicle until the following condition is satisfied.

CAUTION:

Always drive vehicle at safe speed.

2.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Proceed to

EC-204, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000009651064

1.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

Check engine coolant temperature sensor. Refer to

EC-204, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Replace engine coolant temperature sensor.

2.

CHECK THERMOSTAT

Check thermostat. Refer to

CO-24, "Exploded View"

.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace thermostat. Refer to

CO-24, "Exploded View"

.

Component Inspection

INFOID:0000000009651065

1.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

COOLAN TEMP/S

65

°

C (149

°

F) or less

FUEL T/TMP SE

Less than the value calculated by sub-
tracting 24

°

C (43

°

F) from “COOLAN

TEMP/S”.*

COOLAN TEMP/S

FUEL T/TMP SE

70

°

C (158

°

F)

45

°

C (113

°

F) or less

65

°

C (149

°

F)

40

°

C (104

°

F) or less

60

°

C (140

°

F)

35

°

C (95

°

F) or less

COOLAN TEMP/S

65

°

C (149

°

F) or more

P0128 THERMOSTAT FUNCTION

EC-205

< DTC/CIRCUIT DIAGNOSIS >

[VQ35DE]

C

D

E

F

G

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EC

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P

O

1.

Turn ignition switch OFF.

2.

Disconnect engine coolant temperature sensor harness connector.

3.

Remove engine coolant temperature sensor. Refer to

CO-26, "Exploded View"

.

4.

Check resistance between engine coolant temperature sensor
terminals as per the following.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace engine coolant temperature sensor. Refer to

CO-26, "Exploded View"

.

Terminals

Condition

Resistance (k

Ω

)

1 and 2

Temperature [

°

C (

°

F)]

20 (68)

2.1 - 2.9

50 (122)

0.68 - 1.00

90 (194)

0.236 - 0.260

JMBIA0080ZZ