engine coolant INFINITI FX35 2005 Service Manual

DTC P0011, P0021 IVT CONTROL EC-865
[VK45DE]
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Revision: 2005 July 2005 FX
DTC P0011, P0021 IVT CONTROLPFP:23796
DescriptionABS007IO
SYSTEM DESCRIPTION
*: This signal is sent to the ECM through CAN communication line
This mechanism hydraulically controls cam phases continuously with the fixed operating angle of the intake
valve.
The ECM receives signals such as crankshaft position, camshaft position, engine speed, and engine coolant
temperature. Then, the ECM sends ON/OFF pulse duty signals to the intake valve timing (IVT) control sole-
noid valve depending on driving status. This makes it possible to control the shut/open timing of the intake
valve to increase engine torque in low/mid speed range and output in high-speed range.
COMPONENT INSPECTION
Intake Valve Timing Control Solenoid Valve
Intake Valve Timing (IVT) control solenoid valve is activated by ON/
OFF pulse duty (ratio) signals from the ECM.
The IVT control solenoid valve changes the oil amount and direction
of flow through intake valve timing control unit or stops oil flow.
The longer pulse width advances valve angle.
The shorter pulse width retards valve angle.
When ON and OFF pulse widths become equal, the solenoid valve
stops oil pressure flow to fix the intake valve angle at the control
position.
Sensor Input signal to ECM function ECM Actuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed
Intake valve
timing control Intake valve timing control
solenoid valve
Intake valve timing control position sensor Intake valve timing signal
Engine coolant temperature sensor Engine coolant temperature
Wheel sensor* Vehicle speed
PBIB1102E
PBIB1842E

DTC P0031, P0032, P0051, P0052 HO2S1 HEATER EC-877
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Revision: 2005 July 2005 FX
DTC P0031, P0032, P0051, P0052 HO2S1 HEATERPFP:22690
DescriptionABS007IW
SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the heated oxygen sensor 1 heater corresponding to the engine speed
and engine coolant temperature. The duty percent varies with engine coolant temperature when engine is
started.
OPERATION
CONSULT-II Reference Value in Data Monitor ModeABS007IX
Specification data are reference values.
On Board Diagnosis LogicABS007IY
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS) Engine speed
Heated oxygen sensor 1
heater control Heated oxygen sensor 1 heater
Engine coolant temperature sensor Engine coolant temperature
Engine speed rpm Heated oxygen sensor 1 heater
Above 3,000 OFF
Below 3,000 after warming up ON
MONITOR ITEM CONDITION SPECIFICATION
HO2S1 HTR (B1)
HO2S1 HTR (B2)

Engine: After warming up

Engine speed: Below 3,000 rpm ON

Engine speed: Above 3,000 rpm OFF
DTC No.
Trouble diagnosis
name DTC detecting condition Possible cause
P0031
0031
(Bank 1) Heated oxygen
sensor 1 heater
control circuit low The current amperage in the heated oxygen
sensor 1 heater circuit is out of the normal
range.
(An excessively low voltage signal is sent to
ECM through the heated oxygen sensor 1
heater.)

Harness or connectors
(The heated oxygen sensor 1 heater circuit is
open or shorted.)

Heater oxygen sensor 1 heater
P0051
0051
(Bank 2)
P0032
0032
(Bank 1) Heated oxygen
sensor 1 heater
control circuit high The current amperage in the heated oxygen
sensor 1 heater circuit is out of the normal
range.
(An excessively high voltage signal is sent to
ECM through the heated oxygen sensor 1
heater.)

Harness or connectors
(The heated oxygen sensor 1 heater circuit is
shorted.)

Heater oxygen sensor 1 heater
P0052
0052
(Bank 2)

DTC P0037, P0038, P0057, P0058 HO2S2 HEATER EC-885
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Revision: 2005 July 2005 FX
DTC P0037, P0038, P0057, P0058 HO2S2 HEATERPFP:226A0
DescriptionABS007J4
SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the heated oxygen sensor 2 heater corresponding to the engine speed,
amount of intake air and engine coolant temperature.
OPERATION
CONSULT-II Reference Value in Data Monitor ModeABS007J5
Specification data are reference values.
On Board Diagnosis LogicABS007J6
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS) Engine speed
Heated oxygen sensor 2
heater control Heated oxygen sensor 2 heater
Engine coolant temperature sensor Engine coolant temperature
Mass air flow sensor Amount of intake air
Engine speed rpm Heated oxygen sensor 2 heater
Above 3,600 OFF
Below 3,600 rpm after the following conditions are met.

Engine: After warming up

Keeping the engine speed between 3,500 and 4,000 rpm for 1
minute and at idle for 1 minute under no load ON
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 HTR (B1)
HO2S2 HTR (B2)

Engine speed: Below 3,600 rpm after the following conditions are met.
–Engine: After warming up
–Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and
at idle for 1 minute under no load ON

Engine speed: Above 3,600 rpm OFF
DTC No.
Trouble diagnosis
name DTC detecting condition Possible cause
P0037
0037
(Bank 1) Heated oxygen
sensor 2 heater
control circuit low The current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)

Harness or connectors
(The heated oxygen sensor 2 heater circuit is
open or shorted.)

Heater oxygen sensor 2 heater
P0057
0057
(Bank 2)
P0038
0038
(Bank 1) Heated oxygen
sensor 2 heater
control circuit high The current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to
ECM through the heated oxygen sensor 2
heater.)

Harness or connectors
(The heated oxygen sensor 2 heater circuit is
shorted.)

Heater oxygen sensor 2 heater
P0058
0058
(Bank 2)

EC-914
[VK45DE]
DTC P0117, P0118 ECT SENSOR
Revision: 2005 July 2005 FX
DTC P0117, P0118 ECT SENSORPFP:22630
Component DescriptionABS007K0
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.

*: These data are reference values and are 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 LogicABS007K1
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 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.
Detected items Engine operating condition in fail-safe mode
Engine coolant temper- ature 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-917
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Revision: 2005 July 2005 FX
Diagnostic ProcedureABS007K4
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-861, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2. CHECK ECT SENSOR POWER SUPPLY CIRCUIT
1. Disconnect engine coolant temperature (ECT) sensor harness connector.
2. Turn ignition switch ON.
3. Check voltage between ECT sensor terminal 1 and ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. DETECT MALFUNCTIONING RART
Check the following.

Harness connector F261, F24

Harness for open or short between ECM and engine coolant temperature sensor
>> Repair open circuit or short to ground or short to power in harness or connectors.
PBIB2195E
Voltage: Approximately 5V
PBIB1515E
PBIB0080E

EC-918
[VK45DE]
DTC P0117, P0118 ECT SENSOR
Revision: 2005 July 2005 FX
4. CHECK ECT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECT sensor terminal 2 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 6.
NG >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.

Harness connector F261, F24

Harness for open and short between ECT sensor and ECM
>> Repair open circuit or short to ground or short to power in harness or connectors.
6. CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-919, "
Component Inspection" .
OK or NG
OK >> GO TO 7.
NG >> Replace engine coolant temperature sensor.
7. CHECK INTERMITTENT INCIDENT
Refer to EC-854, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>> INSPECTION END
Continuity should exist.

DTC P0117, P0118 ECT SENSOR EC-919
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Revision: 2005 July 2005 FX
Component InspectionABS007K5
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.

2. If NG, replace engine coolant temperature sensor.
Removal and InstallationABS007K6
ENGINE COOLANT TEMPERATURE SENSOR
Refer to EM-229, "CYLINDER HEAD" .
PBIB2005E
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

DTC P0125 ECT SENSOR EC-927
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Revision: 2005 July 2005 FX
DTC P0125 ECT SENSORPFP:22630
Component DescriptionABS007KF
NOTE:
If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or
P0118. Refer to EC-914
.
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.

*: These data are reference values and are 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 LogicABS007KG
This self-diagnosis has the one trip detection logic.
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
P0125
0125 Insufficient engine cool-
ant temperature for
closed loop fuel control

Voltage sent to ECM from the sensor is not
practical, even when some time has passed
after starting the engine.

Engine coolant temperature is insufficient for
closed loop fuel control.

Harness or connectors
(High resistance in the circuit)

Engine coolant temperature sensor

Thermostat

EC-928
[VK45DE]
DTC P0125 ECT SENSOR
Revision: 2005 July 2005 FX
DTC Confirmation ProcedureABS007KH
CAUTION:
Be careful not to overheat engine.
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. Check that “COOLAN TEMP/S” is above 10 °C (50 °F).
If it is above 10 °C (50 °F), the test result will be OK.
If it is below 10 °C (50 °F), go to following step.
4. Start engine and run it for 65 minutes at idle speed. If “COOLAN TEMP/S” increases to more than 10 °C (50 °F)
within 65 minutes, stop engine because the test result will
be OK.
5. If DTC is detected, go to EC-928, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnostic ProcedureABS007KI
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-861, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2. CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-929, "
Component Inspection" .
OK or NG
OK >> GO TO 3.
NG >> Replace engine coolant temperature sensor.
SEF174Y
PBIB2195E

DTC P0125 ECT SENSOR EC-929
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Revision: 2005 July 2005 FX
3. CHECK THERMOSTAT OPERATION
When the engine is cold [lower than 70 °C (158 °F)] condition, grasp lower radiator hose and confirm the engine
coolant does not flow.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace thermostat. Refer to CO-53, "
THERMOSTAT AND WATER CONTROL VALVE" .
4. CHECK INTERMITTENT INCIDENT
Refer to EC-854, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
Refer to EC-916, "
Wiring Diagram" .
>> INSPECTION END
Component InspectionABS007KJ
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.

2. If NG, replace engine coolant temperature sensor.
Removal and InstallationABS007KK
ENGINE COOLANT TEMPERATURE SENSOR
Refer to CO-53, "THERMOSTAT AND WATER CONTROL VALVE" .
PBIB2005E
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