Nissan Frontier. Manual - part 523

P0128 THERMOSTAT FUNCTION

EC-663

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

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P0128 THERMOSTAT FUNCTION

On Board Diagnosis Logic

INFOID:0000000009481318

NOTE:

If DTC P0128 is displayed with DTC P0300, P0301, P0302, P0303, P0304, P0305 or P0306, first perform

the trouble diagnosis for DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306. Refer to 

EC-730,

"DTC Confirmation Procedure"

.

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

INFOID:0000000009481319

NOTE:

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-

ing 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.

 WITH CONSULT

TESTING CONDITION:

• For best results, perform at ambient temperature of –10

°C (14°F) or higher.

• For best results, perform at engine coolant temperature of –10

°C (14°F) to 58°C (136°F).

• Before performing the following procedure, do not add fuel.
1. Turn A/C switch OFF.
2. Turn blower fan switch OFF.
3. Turn ignition switch ON.
4. Select “COOLAN TEMP/S” in “DATA MONITOR” mode with CONSULT.
5. Check the indication of “COOLAN TEMP/S”.

If it is below 58

°C (136°F), go to following step.

If it is above 58

°C (136°F), cool down the engine to less than 58°C (136°F). Then go to next steps.

6. Start engine and wait at idle for at least 10 minutes under the following conditions.

CAUTION:

Always drive vehicle at a safe speed.

NOTE:

If “COOLAN TEMP/S” increases to more than 71

°C (160°F) within 30 minutes, turn ignition switch

OFF because the test result will be OK.

7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to 

EC-663, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT” above.

Diagnosis Procedure

INFOID:0000000009481320

1.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

Refer to 

EC-664, "Component Inspection"

.

OK or NG

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0128
0128

Thermostat function

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

• Thermostat
• Leakage from sealing portion of thermostat
• Engine coolant temperature sensor

VHCL SPEED SE

More than 56 km/h (35MPH)

EC-664

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

P0128 THERMOSTAT FUNCTION

OK

>> GO TO 2.

NG

>> Replace engine coolant temperature sensor. Refer to 

CO-57, "Exploded View"

.

2.

CHECK THERMOSTAT

Refer to 

CO-55, "Removal and Installation"

.

OK or NG

OK

>> INSPECTION END

NG

>> Replace thermostat.

Component Inspection

INFOID:0000000009481321

ENGINE COOLANT TEMPERATURE SENSOR

1. Check resistance between engine coolant temperature sensor

terminals 1 and 2 as shown in the figure.

<Reference data>

2. If NG, replace engine coolant temperature sensor.

JMBIA0080ZZ

Engine coolant temperature [

°C (°F)]

Resistance (k

Ω)

20 (68)

2.1 - 2.9

50 (122)

0.68 - 1.00

90 (194)

0.236 - 0.260

SEF012P

P0130, P0150 A/F SENSOR 1

EC-665

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

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P0130, P0150 A/F SENSOR 1

Component Description

INFOID:0000000009481322

The air fuel ratio (A/F) sensor 1 is a planar one-cell limit current sen-

sor. The sensor element of the A/F sensor 1 is composed an elec-

trode layer, which transports ions. It has a heater in the element.
The sensor is capable of precise measurement   = 1, but also in the

lean and rich range. Together with its control electronics, the sensor
outputs a clear, continuous signal throughout a wide   range.

The exhaust gas components diffuse through the diffusion layer at

the sensor cell. An electrode layer is applied voltage, and this current

relative oxygen density in lean. Also this current relative hydrocar-

bon density in rich.

Therefore, the A/F sensor 1 is able to indicate air fuel ratio by this

electrode layer of current. In addition, a heater is integrated in the

sensor to ensure the required operating temperature of about 800

°C

(1,472

°F).

On Board Diagnosis Logic

INFOID:0000000009481323

To judge the malfunctions, the diagnosis checks that the A/F signal computed by ECM from the air fuel ratio

(A/F) sensor 1 signal fluctuates according to fuel feedback control.

DTC Confirmation Procedure

INFOID:0000000009481324

Perform PROCEDURE FOR MALFUNCTION A first.

If the DTC cannot be confirmed, perform PROCEDURE FOR MALFUNCTION B.

NOTE:

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-

ing the next step.
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.
TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is more than 11V at idle.

PROCEDURE FOR MALFUNCTION A

1. Start engine and warm it up to normal operating temperature.

2. Let engine idle for 2 minutes.

3. Check 1st trip DTC.

4. If 1st trip DTC is detected, go to 

EC-666, "Diagnosis Procedure"

.

JPBIA4038GB

JPBIA5446GB

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible Cause

P0130
0130
(Bank 1)

Air fuel ratio (A/F) sensor 1 
circuit

A)

The A/F signal computed by ECM from the A/F 
sensor 1 signal is constantly in a range other 
than approx. 2.2V.

• Harness or connectors

(The A/F sensor 1 circuit is open 
or shorted.)

• Air fuel ratio (A/F) sensor 1

P0150
0150
(Bank 2)

B)

The A/F signal computed by ECM from the A/F 
sensor 1 signal is constantly approx. 2.2V.

EC-666

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

P0130, P0150 A/F SENSOR 1

PROCEDURE FOR MALFUNCTION B

CAUTION:

Always drive vehicle at a safe speed.

 With CONSULT

1. Start engine and warm it up to normal operating temperature.

2. Select “A/F SEN1 (B1)” or “A/F SEN1 (B2)” in “DATA MONITOR” mode with CONSULT.

3. Check “A/F SEN1 (B1)” or “A/F SEN1 (B2)” indication.

If the indication is constantly approx. 2.2V and does not fluctuates, go to 

EC-666, "Diagnosis Procedure"

.

If the indication fluctuate around 2.2V, go to next step.

4. Select “A/F SEN1 (B1) P1276” (for DTC P0130) or “A/F SEN1 (B2) P1286” (for DTC P0150) of “A/F

SEN1” in “DTC WORK SUPPORT” mode with CONSULT.

5. Touch “START”.

6. When the following conditions are met, “TESTING” will be displayed on the CONSULT screen.

If “TESTING” is not displayed after 20 seconds, retry from step 2.

7. Release accelerator pedal fully.

NOTE:

Never apply brake when releasing the accelerator pedal.

8. Check that “TESTING” changes to “COMPLETED”.

If “TESTING” changed to “OUT OF CONDITION”, retry from step 6.

9. Check that “OK” is displayed after touching “SELF-DIAG RESULT”. 

If “NG” is displayed, go to 

EC-666, "Diagnosis Procedure"

.

Overall Function Check

INFOID:0000000009481325

PROCEDURE FOR MALFUNCTION B

Use this procedure to check the overall function of the A/F sensor 1 circuit. During this check, a 1st trip DTC

might not be confirmed.

 With GST

1. Start engine and warm it up to normal operating temperature.

2. Drive the vehicle at a speed of 80 km/h (50 MPH) for a few minutes in the suitable gear position.

3. Set D position with “OD” OFF (A/T) or 5th position (M/T), then release the accelerator pedal fully until the

vehicle speed decreases to 50 km/h (30 MPH).

NOTE:

Never apply brake during releasing the accelerator pedal.

4. Repeat steps 2 and 3 for five times.

5. Stop the vehicle and turn ignition switch OFF.

6. Turn ignition switch ON.

7. Turn ignition switch OFF and wait at least 10 seconds.

8. Restart engine.

9. Repeat steps 2 and 3 for five times.

10. Stop the vehicle and connect GST to the vehicle.

11. Check that no 1st trip DTC is displayed.

If the 1st trip DTC is displayed, go to 

EC-666, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000009481326

1.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten three ground screws on the body. Refer to 

EC-617, "Ground Inspection"

.

OK or NG

ENG SPEED

1,100 - 3,200 rpm

VHCL SPEED SE

More than 64 km/h (40 MPH)

B/FUEL SCHDL

1.0 - 8.0 msec

Shift lever

D position with “OD” OFF (A/T)
5th position (M/T)