2007 INFINITI QX56 check engine

DTC P0128 THERMOSTAT FUNCTION
EC-223
< SERVICE INFORMATION >
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DTC P0128 THERMOSTAT FUNCTION
On Board Diagnosis LogicINFOID:0000000003531731
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 stuck open.
DTC Confirmation ProcedureINFOID:0000000003531732
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.
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 72°C (162°F).
WITH CONSULT-II
1. Replace thermostat with new one. Refer to CO-20 . Use only a genuine NISSAN thermostat as a replace-
ment. If an incorrect thermostat is used, the MIL may come on.
2. Turn ignition switch ON.
3. Select “COOLAN TEMP/S” in “DATA MONITOR” mode with CONSULT-II.
4. Check that the “COOLAN TEMP/S” is above 72°C (162°F).
If it is below 72°C (162°F), go to following step.
If it is above 72°C (162°F), cool down the engine to less than 72°C (162°F), then retry from step 1.
5. Drive vehicle for 10 consecutive minutes under the following conditions.
If 1st trip DTC is detected, go to EC-223, "
Diagnosis Procedure" .
WITH GST
1. Follow the procedure “WITH CONSULT-II” above.
Diagnosis ProcedureINFOID:0000000003531733
1.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-223, "
Component Inspection" .
OK or NG
OK >>INSPECTION END
NG >> Replace engine coolant temperature sensor.
Component InspectionINFOID:0000000003531734
ENGINE COOLANT TEMPERATURE SENSOR
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0128
0128Thermostat functionThe 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 80 - 120 km/h (50 - 75 MPH)

EC-224
< SERVICE INFORMATION >
DTC P0128 THERMOSTAT FUNCTION
1. Check resistance between engine coolant temperature sensor
terminals as shown in the figure.

2. If NG, replace engine coolant temperature sensor.
Removal and InstallationINFOID:0000000003531735
ENGINE COOLANT TEMPERATURE SENSOR
Refer to CO-20 .
PBIB2005E
Temperature °C (°F) Resistance kΩ
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.0
90 (194) 0.236 - 0.260
SEF012P

DTC P0130, P0150 A/F SENSOR 1
EC-225
< SERVICE INFORMATION >
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DTC P0130, P0150 A/F SENSOR 1
Component DescriptionINFOID:0000000003531736
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).
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003531737
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531738
To judge the malfunction, the diagnosis checks that the A/F signal computed by ECM from the A/F sensor 1
signal fluctuates according to fuel feedback control.
DTC Confirmation ProcedureINFOID:0000000003531739
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 turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
PROCEDURE FOR MALFUNCTION A
PBIB3353E
PBIB3354E
MONITOR ITEM CONDITION SPECIFICATION
A/F SEN1 (B1)
A/F SEN1 (B2)• Engine: After warming upMaintaining engine speed at
2,000 rpmFluctuates around 2.2V
DTC No. Trouble diagnosis name DTC detecting condition Possible Cause
P0130
0130
(Bank 1)
Air fuel ratio (A/F) sensor 1
circuitA)The A/F signal computed by ECM from the A/F
sensor 1 signal is constantly in the 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-226
< SERVICE INFORMATION >
DTC P0130, P0150 A/F SENSOR 1
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Let engine idle for 2 minutes.
4. If 1st trip DTC is detected, go to EC-231, "
Diagnosis Procedure".
With GST
Follow the procedure “With CONSULT-II” above.
PROCEDURE FOR MALFUNCTION B
CAUTION:
Always drive vehicle at a safe speed.
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select “A/F SEN1 (B1)” in “DATA MONITOR” mode with CONSULT-II.
3. Check “A/F SEN1 (B1)” indication.
If the indication is constantly approx. 2.2V and does not fluctuates, go to EC-231, "
Diagnosis Procedure".
If the indication fluctuates around 2.2V, go to next step.
4. Select “A/F SEN1 (B1) P1276” (for DTC P0130) of “A/F SEN1” in “DTC WORK SUPPORT” mode with
CONSULT-II.
5. Touch “START”.
6. When the following conditions are met, “TESTING” will be dis-
played on the CONSULT-II screen.
If “TESTING” is not displayed after 20 seconds, retry from
step 2.
7. Release accelerator pedal fully.
NOTE:
Never apply brake during releasing the accelerator pedal.
SEF174Y
ENG SPEED 850 - 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
SEF576Z
SEF577Z

DTC P0130, P0150 A/F SENSOR 1
EC-227
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8. Make sure that “TESTING” changes to “COMPLETED”.
If “TESTING” changed to “OUT OF CONDITION”, retry from
step 6.
9. Make sure that “OK” is displayed after touching “SELF-DIAG
RESULT”.
If “NG” is displayed, go to EC-231, "
Diagnosis Procedure".
Overall Function CheckINFOID:0000000003531740
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 shift lever to D position, 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. Wait at least 10 seconds and restart engine.
7. Repeat steps 2 and 3 for five times.
8. Stop the vehicle and connect GST to the vehicle.
9. Make sure that no 1st trip DTC is displayed.
If the 1st trip DTC is displayed, go to EC-231, "
Diagnosis Procedure".
SEF578Z

DTC P0130, P0150 A/F SENSOR 1
EC-231
< SERVICE INFORMATION >
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: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis ProcedureINFOID:0000000003531742
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-143, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect A/F sensor 1 harness connector.
2. Turn ignition switch ON.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
16 G/L A/F sensor 1 (bank 2)[Engine is running]
•Warm-up condition
• Engine speed: 2,000 rpmApproximately 1.8V
Output voltage varies with air fuel
ratio.
24
43GR/G
GR/GA/F sensor 1 heater (bank 2)[Engine is running]
•Warm-up condition
• Idle speed
(More than 140 seconds after starting en-
gine)Approximately 2.9 - 8.8V
75 L/P A/F sensor 1 (bank 2)[Ignition switch: ON]Approximately 2.2V
PBIA8148J
BBIA0354E
BBIA0376E

EC-234
< SERVICE INFORMATION >
DTC P0131, P0151 A/F SENSOR 1
DTC P0131, P0151 A/F SENSOR 1
Component DescriptionINFOID:0000000003531744
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).
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003531745
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531746
To judge the malfunction, the diagnosis checks that the A/F signal computed by ECM from the A/F sensor 1
signal is not inordinately low.
DTC Confirmation ProcedureINFOID:0000000003531747
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10.5V at idle.
WITH CONSULT-II
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-II.
PBIB3353E
PBIB3354E
MONITOR ITEM CONDITION SPECIFICATION
A/F SEN1 (B1)
A/F SEN1 (B2)• Engine: After warming upMaintaining engine speed at
2,000 rpmFluctuates around 2.2V
DTC No. Trouble diagnosis name DTC detecting condition Possible Cause
P0131
0131
(Bank 1)
Air fuel ratio (A/F) sensor 1
circuit low voltage• The A/F signal computed by ECM from the A/
F sensor 1 signal is constantly approx. 0V.• Harness or connectors
(The A/F sensor 1 circuit is open or
shorted.)
• Air fuel ratio (A/F) sensor 1 P0151
0151
(Bank 2)

DTC P0131, P0151 A/F SENSOR 1
EC-235
< SERVICE INFORMATION >
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3. Check “A/F SEN1 (B1)” or “A/F SEN1 (B2)” indication.
If the indication is constantly approx. 0V, go to EC-239, "
Diagno-
sis Procedure".
If the indication is not constantly approx. 0V, go to next step.
4. Turn ignition switch OFF, wait at least 10 seconds and then
restart engine.
5. Drive and accelerate vehicle to more than 40 km/h (25 MPH)
within 20 seconds after restarting engine.
6. Maintain the following conditions for about 20 consecutive sec-
onds.
NOTE:
•Keep the accelerator pedal as steady as possible during the cruising.
•If this procedure is not completed within 1 minute after restarting engine at step 4, return to step
4.
7. If 1st trip DTC is displayed, go to EC-239, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
ENG SPEED 1,000 - 3,200 rpm
VHCL SPEED SE More than 40 km/h (25 MPH)
B/FUEL SCHDL 1.5 - 9.0 msec
Gear position Suitable position
SEF581Z