2009 NISSAN LATIO ignition

P0116 ECT SENSOR
EC-165
< COMPONENT DIAGNOSIS >
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P0116 ECT SENSOR
Description INFOID:0000000004780447
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 38
(Engine coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output vo ltage. Doing so may result in damage to the ECM's transis-
tor. Use a ground other than ECM terminals, such as the ground.
DTC Logic INFOID:0000000004780084
DTC DETECTION LOGIC NOTE:
If DTC P0116 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117,
P0118. Refer to EC-167, " DTC Logic " .
DTC CONFIRMATION PROCEDURE 1.
PRECONDITIONING
If DTC confirmation procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
>> GO TO 2. 2.
PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and warm it up to normal operating temperature.
2. Rev engine up to 2,000 rpm for more than 10 minutes.
3. Move the vehicle to a cool place, then stop engine and turn ignition switch OFF.
4. Check resistance between “fuel level s ensor unit and fuel pump” terminals 4 and 5. SEF594K
Engine coolant temperature
[° C ( °F)] Voltage* (V) Resistance (k
Ω)
–10 (14) 4.4 7.0 - 11.4 20 (68) 3.5 2.37 - 2.63
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
P0116 Engine coolant temperature
sensor circuit range/perfor-
mance Engine coolant temperature signal from engine
coolant temperature sensor does not fluctuate,
even when some time has passed after starting
the engine with pre-warming up condition. • Harness or connectors
(High or low resistance in the circuit)
• Engine coolant temperature sensor

P0117, P0118 ECT SENSOR
EC-167
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P0117, P0118 ECT SENSOR
Description INFOID:0000000004780087
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 38
(Engine coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output vo ltage. Doing so may result in damage to the ECM's transis-
tor. Use a ground other than ECM terminals, such as the ground.
DTC Logic INFOID:0000000004780088
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE 1.
PRECONDITIONING
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
>> GO TO 2. 2.
PERFORM DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON and wait at least 5 seconds.
2. Check DTC.
Is DTC detected? YES >> Go to
EC-168, " Diagnosis Procedure " .
NO >> INSPECTION END SEF594K
Engine coolant temperature
[° C ( °F)] Voltage* (V) Resistance (k
Ω)
–10 (14) 4.4 7.0 - 11.4 20 (68) 3.5 2.37 - 2.63
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 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 Engine coolant temperature
sensor circuit high input An excessively high voltage from the sensor
is sent to ECM.

Diagnosis Procedure " .
>> INSPECTION END
Component Inspection INFOID:0000000004780094THROTTLE VALVE CLOSED POSITION LEARNING : Special Repair Requirement " .
4. Turn ignition switch ON.
5. Set selector lever to D (A/T) or 1st (M/T) position.
6. Check the voltage between ECM harness connector and
ground.
Is the inspection result normal? YES >> INSPECTION END
NO >> GO TO 2. Special Repair Requirement " .
>> INSPECTION END
Special Repair Requirement INFOID:0000000004780095THROTTLE VALVE CLOSED POSITION LE
ARNING : Special Repair Requirement "
>> GO TO 2.
IDLE AIR VOLUME LEARNING : Special Repair Requirement "
>> ENDECM
Ground Condition Voltage
Connector Terminal
F11 33
(TP sensor
1 signal)
GroundAccelerator
pedal Fully released
More than
0.36V
Fully de-
pressed Less than
4.75V
34
(TP sensor 2 signal) Fully released
Less than
4.75V
Fully de-
pressed More than
0.36V

P0125 ECT SENSOR
EC-175
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P0125 ECT SENSOR
Description INFOID:0000000004780096
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 38
(Engine coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output vo ltage. Doing so may result in damage to the ECM's transis-
tor. Use a ground other than ECM terminals, such as the ground.
DTC Logic INFOID:0000000004780097
DTC DETECTION LOGIC NOTE:
• If DTC P0125 is displayed with P0 116, first perform the trouble diagnosis for DTC P0116. Refer to EC-165, " DTC Logic " .
• If DTC P0125 is displayed with P0117 or P0118, fi rst perform the trouble diagnosis for DTC P0117 or
P0118. Refer to EC-167, " DTC Logic " .
DTC CONFIRMATION PROCEDURE 1.
PRECONDITIONING
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
>> GO TO 2. 2.
CHECK ENGINE COOLANT TEMPERATURE SENSOR FUNCTION
With CONSULT-III
1. Turn ignition switch ON. SEF594K
Engine coolant temperature
[° C ( °F)] Voltage* (V) Resistance (k
Ω)
–10 (14) 4.4 7.0 - 11.4 20 (68) 3.5 2.37 - 2.63
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 Insufficient engine coolant
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-178< COMPONENT DIAGNOSIS >
[HR16DE]
P0127 IAT SENSOR
P0127 IAT SENSOR
Description INFOID:0000000004780100
The intake air temperature sensor is built-into mass air flow sensor
(1). The sensor detects intake air temperature and transmits a signal
to the ECM.
The temperature sensing unit uses a thermistor which is sensitive to
the change in temperature. Electrical resistance of the thermistor
decreases in response to the temperature rise.

*: These data are reference values and are measured between ECM terminal 46
(Intake air temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing
so may result in damage to the ECM's transistor. Use a ground other than ECM
terminals, such as the ground.
DTC Logic INFOID:0000000004780101
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE 1.
PRECONDITIONING
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
This test may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road
test is expected to be easier, it is unnecessary to lift the vehicle.
>> GO TO 2. 2.
PERFORM DTC CONFIRMATION PROCEDURE
With CONSULT-III
1. Wait until engine coolant temperature is less than 96 °C (205 °F)
- Turn ignition switch ON.
- Select “DATA MONITOR” mode with CONSULT-III.
- Check the engine coolant temperature.
- If the engine coolant temperature is not less than 96 °C (205 °F), turn ignition switch OFF and cool down
engine. PBIA9559J
Intake air temperature
[° C ( °F)] Voltage* (V) Resistance (k
Ω)
25 (77) 3.3 1.800 - 2.200
80 (176) 1.2 0.283 - 0.359 SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0127 Intake air temperature
too high Rationally incorrect voltage from the sensor is
sent to ECM, compared with the voltage signal
from engine coolant temperature sensor. • Harness or connectors
(The sensor circuit is open or shorted)
• Intake air temperature sensor

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NOTE:
Perform the following steps before engine coolant temperature is above 96 °C (205 °F).
2. Turn ignition switch ON.
3. Select “DATA MONITOR” mode with CONSULT-III.
4. Start engine.
5. Hold vehicle speed at more than 70 km/h (43 MPH) for 95 consecutive seconds.
CAUTION:
Always drive vehicle at a safe speed.
6. Check 1st trip DTC.
With GST
Follow the procedure “With CONSULT-III” above.
Is 1st trip DTC detected? YES >> Go to
EC-179, " Diagnosis Procedure " .
NO >> INSPECTION END
Diagnosis Procedure INFOID:0000000004780102Ground Inspection " .
Is the inspection result normal? YES >> GO TO 2.
NO >> Repair or replace ground connection. Component Inspection " .
Is the inspection result normal? YES >> GO TO 3.
NO >> Replace mass air flow sensor ( with intake air temperature sensor).Diagnosis Procedure " .
>> INSPECTION END
Component Inspection INFOID:0000000004780103YES >> INSPECTION END
NO >> Replace mass air flow sensor ( with intake air temperature sensor).

P0128 THERMOSTAT FUNCTION
EC-181
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Is the inspection result normal? YES >> GO TO 2.
NO >> Replace engine coolant temperature sensor. 2.
CHECK THERMOSTAT
Refer to CO-23, " Inspection " .
Is the inspection result normal? YES >> INSPECTION END
NO >> Replace thermostat.
Component Inspection INFOID:00000000047801061.
CHECK ENGINE COOLANT TEMPERATURE SENSOR
1. Turn ignition switch OFF.
2. Disconnect engine coolant temperature sensor harness connector.
3. Remove engine coolant temperature sensor.
4. Check resistance between engine coolant temperature sensor terminals by heating with hot water as shown in the figure.
Is the inspection result normal? YES >> INSPECTION END
NO >> Replace engine coolant temperature sensor. Terminals Condition Resistance
1 and 2 Temperature [ °C ( °F)] 20 (68) 2.37 - 2.63 k
Ω
50 (122) 0.68 - 1.00 k Ω
90 (194) 0.236 - 0.260 k Ω PBIB2005E

EC-186< COMPONENT DIAGNOSIS >
[HR16DE]
P0130 A/F SENSOR 1
YES >> GO TO 2.
NO >> Repair or replace ground connection. 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.
3. Check the voltage between A/F sensor 1 harness connector and
ground.
Is the inspection result normal? YES >> GO TO 4.
NO >> GO TO 3. 3.
DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors E8, F8
• IPDM E/R harness connector E45
• 10 A fuse (No. 54)
• Harness for open or short between A/F sensor 1 and fuse
>> Repair or replace harness or connectors. 4.
CHECK A/F SENSOR 1 INPUT SIGN AL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
4. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector
and ground.
5. Also check harness for short to power.
Is the inspection result normal? YES >> GO TO 5.
NO >> Repair open circuit or short to ground or short to power in harness or connectors. 5.
CHECK INTERMITTENT INCIDENT
Perform EC-120, " Diagnosis Procedure " .
A/F sensor 1
Ground Voltage
Connector Terminal
F12 4 Ground Battery voltage PBIB3308E
A/F sensor 1 ECM
Continuity
Connector Terminal Connector Terminal
F12 1
F11 49
Existed
2 53
A/F sensor 1 Ground Continuity
Connector Terminal
F12 1
Ground Not existed
2
ECM Ground Continuity
Connector Terminal
F11 49
Ground Not existed
53