Nissan Primera P11. Instruction — part 90
COMPONENT INSPECTION
Mass air flow sensor
1. Turn ignition switch to “ON” position.
2. Start engine and warm it up sufficiently.
3. Check voltage between mass air flow sensor connector ter-
minal
p
5
and ground.
Conditions
Voltage V
Ignition switch “ON” position (Engine stopped.)
Approximately 1.0
Idle (Engine is warmed-up sufficiently.)
1.9 - 2.3
4. If NG, remove mass air flow sensor from air duct. Check hot
film for damage or dust.
NEF792
Mass air flow sensor
connector
NEF669
TROUBLE DIAGNOSIS 1
CD20T
Mass Air Flow Sensor (MAFS) (Cont’d)
EC-65
Engine Coolant Temperature (ECT) Sensor
The engine coolant temperature sensor is used to detect the
engine coolant temperature. The sensor modifies a voltage sig-
nal 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
thermistor
decreases
as
temperature
increases.
<Reference data>
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)
2.3
0.68 - 1.00
90 (194)
1.0
0.236 - 0.260
Malfunction is detected when ...
Check Items
(Possible Cause)
●
An excessively high or low voltage from the sensor is
entered to ECM.
●
Harness or connectors
(The sensor circuit is open or shorted.)
●
Engine coolant temperature sensor
DIAGNOSTIC TROUBLE CONFIRMATION
PROCEDURE
1)
Turn ignition switch to “ON” position.
2)
Select “DATA MONITOR” mode with CONSULT-II.
3)
Wait at least 5 seconds.
SEF594K
SEF012P
TROUBLE DIAGNOSIS 2
CD20T
EC-66
YEC800
ENGINE COOLANT
TEMPERATURE
SENSOR
: Detectable line for DTC
: Non-detectable line for DTC
ECM
TROUBLE DIAGNOSIS 2
CD20T
Engine Coolant Temperature (ECT) Sensor
(Cont’d)
EC-67
DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY.
1. Turn ignition switch to “LOCK” posi-
tion.
2. Disconnect engine coolant tempera-
ture sensor harness connector.
3. Turn ignition switch to “ON” position.
4. Check voltage between engine cool-
ant temperature sensor connector
terminal
p
2
and ground with CON-
SULT-II or tester.
Voltage:
Approximately 4.9V
OK
E
NG
Repair harness or con-
nectors.
CHECK GROUND CIRCUIT.
1. Turn ignition switch to “LOCK” posi-
tion.
2. Check harness continuity between
engine coolant temperature sensor
connector terminal
p
1
and engine
ground.
Continuity should exist.
If OK, check harness for short-cir-
cuit.
OK
E
NG
Repair harness or con-
nectors.
CHECK COMPONENT
(Engine coolant temperature sensor).
Refer to “COMPONENT INSPECTION”
on next page.
OK
E
NG
Replace engine coolant
temperature sensor.
Disconnect and reconnect harness
connectors in the circuit. Then retest.
Trouble is not fixed.
Check ECM pin terminals for damage
and check the connection of ECM har-
ness connector. Reconnect ECM har-
ness connector and retest.
INSPECTION END
NEF401
.
RH strut tower
.
Engine coolant temperature
sensor harness connector
NEF193A
Engine coolant temperature
sensor connector
SEF542P
Engine coolant temperature
sensor connector
H
H
H
H
H
H
TROUBLE DIAGNOSIS 2
CD20T
Engine Coolant Temperature (ECT) Sensor
(Cont’d)
EC-68
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