sensor NISSAN PRIMERA 1999 Electronic Repair Manual

Component DescriptionNCEC0050The mass air flow sensor is placed in the stream of intake air. It
measures the intake flow rate by measuring a part of the entire
intake flow. It consists of a hot wire that is supplied with electric
current from the ECM. The temperature of the hot wire is controlled
by the ECM a certain amount. The heat generated by the hot wire
is reduced as the intake air flows around it. The more air, the
greater the heat loss.
Therefore, the ECM must supply more electric current to maintain
the temperature of the hot wire as air flow increases. The ECM
detects the air flow by means of this current change.
CONSULT-II Reference Value in Data Monitor
Mode
NCEC0051Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
MAS A/F SE -B1IEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 1.0 - 1.7V
2,500 rpm 1.5 - 2.4V
CAL/LD VALUEIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle Not used
2,500 rpm Not used
MASS AIRFLOWIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2.5 - 5.0 g×m/s
2,500 rpm 7.1 - 12.5 g×m/s
ECM Terminals and Reference ValueNCEC0052Specification data are reference values and are measured between each terminal and 48 (ECM ground).
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
61 B Mass air flow sensor[Engine is running]
IWarm-up condition
IIdle speed1.3 - 1.7V
[Engine is running]
IWarm-up condition
IEngine speed is 2,500 rpm1.8 - 2.4V
73 WMass air flow sensor
ground[Engine is running]
IWarm-up condition
IIdle speedApproximately 0V
On Board Diagnosis LogicNCEC0053
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0100*
0100A) An excessively high voltage from the sensor is sent to
ECM when engine is not running.IHarness or connectors
(The sensor circuit is open or shorted.)
IMass air flow sensor
B) An excessively low voltage from the sensor is sent to
ECM when engine is running.IHarness or connectors
(The sensor circuit is open or shorted.)
IIntake air leaks
IMass air flow sensor
*: When this malfunction is detected, the ECM enters fail-safe mode and the MI lights up.
SEF987W
DTC P0100 MASS AIR FLOW SENSOR (MAFS)SR20DE
Component Description
EC-120

Detected items Engine operating condition in fail-safe mode
Mass air flow sensor circuitEngine speed will not rise more than 2,400 rpm due to the fuel
cut.
DTC Confirmation ProcedureNCEC0054Perform ªPROCEDURE FOR MALFUNCTION Aº first. If the 1st
trip DTC cannot be confirmed, perform ªPROCEDURE FOR
MALFUNCTION Bº.
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 9 seconds
before conducting the next test.
PROCEDURE FOR MALFUNCTION ANCEC0054S05With CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 2 seconds.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº, EC-
SR-123.
With GST
Follow the procedure ªWith CONSULT-IIº above.
PROCEDURE FOR MALFUNCTION BNCEC0054S06With CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and wait 2 seconds at most.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº, EC-
SR-123.
With GST
Follow the procedure ªWith CONSULT-IIº above.
NEF068A
NEF068A
DTC P0100 MASS AIR FLOW SENSOR (MAFS)SR20DE
DTC Confirmation Procedure
EC-121

Wiring DiagramNCEC0056
YEC081A
DTC P0100 MASS AIR FLOW SENSOR (MAFS)SR20DE
Wiring Diagram
EC-122

Diagnostic ProcedureNCEC0057
1 INSPECTION START
Which malfunction (A or B) is duplicated?
Malfunction A or B
A©GO TO 3.
B©GO TO 2.
2 CHECK INTAKE SYSTEM
Check the following for connection.
IAir cut
IVacuum hoses
IIntake air passage between air duct to collector
OK or NG
OK©GO TO 3.
NG©Reconnect the parts.
3 RETIGHTEN GROUND SCREWS
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
SEF202X
©GO TO 4.
Intake manifold
collector
Engine
ground
DTC P0100 MASS AIR FLOW SENSOR (MAFS)SR20DE
Diagnostic Procedure
EC-123

4 CHECK POWER SUPPLY-I
1. Disconnect mass air flow sensor harness connector.
SEF203X2. Turn ignition switch ªONº.
3. Check voltage between terminal 2 and ground with CONSULT-II or tester.
SEF996WVoltage: Battery voltage
OK or NG
OK©GO TO 6.
NG©GO TO 5.
5 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E90, F73
IHarness for open or short between ECM relay and mass air flow sensor
IHarness for open or short between mass air flow sensor and ECM
©Repair harness or connectors.
Mass air flow sensor
harness connector
Air cleaner
DTC P0100 MASS AIR FLOW SENSOR (MAFS)SR20DE
Diagnostic Procedure (Cont'd)
EC-124

6 CHECK POWER SUPPLY-II
Check voltage between terminal 4 and ground with CONSULT-II or tester.
SEF201XVoltage: 5V
OK or NG
OK©GO TO 8.
NG©GO TO 7.
7 DETECT MALFUNCTIONING PART
Check the harness for open or short between mass air flow sensor terminal 4 and ECM terminal 111.
©Repair harness.
8 CHECK GROUND CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between mass air flow sensor harness connector terminal 3 and ECM terminal 73.
Refer to wiring diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 9.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
9 CHECK INPUT SIGNAL CIRCUIT
1. Check harness continuity between mass air flow sensor harness connector terminal 5 and ECM terminal 61.
Refer to wiring diagram.
Continuity should exist.
2. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 10.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
10 CHECK MASS AIR FLOW SENSOR
Refer to ªComponent Inspectionº, EC-SR-126.
OK or NG
OK©GO TO 11.
NG©Replace mass air flow sensor.
11 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-SR-114.
©INSPECTION END
DTC P0100 MASS AIR FLOW SENSOR (MAFS)SR20DE
Diagnostic Procedure (Cont'd)
EC-125

Component InspectionNCEC0058MASS AIR FLOW SENSORNCEC0058S011. Turn ignition switch ªONº.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal 61 (Mass air flow sen-
sor signal) and ground.
Conditions Voltage V
Ignition switch ªONº (Engine stopped.)Less than 1.2
Idle (Engine is warmed-up to normal operating
temperature.)1.3 - 1.7
2,500 rpm (Engine is warmed-up to normal operat-
ing temperature.)1.8 - 2.4
Idle to about 4,000 rpm*1.3 - 1.7 to Approx. 4.0
*: Check for linear voltage rise in response to increases to about 4,000 rpm in
engine speed.
4. If the voltage is out of specification, disconnect mass air flow
sensor harness connector and connect it again. Repeat above
check.
5. If NG, remove mass air flow sensor from air duct. Check hot
film for damage or dust.
SEF993W
SEF987W
DTC P0100 MASS AIR FLOW SENSOR (MAFS)SR20DE
Component Inspection
EC-126

Component DescriptionNCEC0066The intake air temperature sensor is built into the mass air flow
sensor. 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.

Intake air temperature
ÉC (ÉF)Resistance
kW
20 (68) 2.2 - 2.6
80 (176) 0.31 - 0.37
*: These data are reference values and are measured between ECM terminal 64
(Intake air temperature sensor) and ECM terminal 48 (ECM ground).
On Board Diagnosis LogicNCEC0067
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0110
0110An excessively low or high voltage from the sensor is sent
to ECM.IHarness or connectors
(The sensor circuit is open or shorted.)
IIntake air temperature sensor
DTC Confirmation ProcedureNCEC0068NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 9 seconds
before conducting the next test.
With CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 5 seconds.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº, EC-
SR-129.
With GST
Follow the procedure ªWith CONSULT-IIº above.
SEF987W
SEF012P
NEF068A
DTC P0110 INTAKE AIR TEMPERATURE SENSORSR20DE
Component Description
EC-127

Wiring DiagramNCEC0069
YEC830
INTAKE AIR
TEMPERATURE
SENSOR: Detectable line for DTC
: Non-detectable line for DTC
: Hyper CVT models
ECM
DTC P0110 INTAKE AIR TEMPERATURE SENSORSR20DE
Wiring Diagram
EC-128

Diagnostic ProcedureNCEC0070
1 CHECK POWER SUPPLY
1. Turn ignition switch ªOFFº.
2. Disconnect mass air flow sensor harness connector.
SEF203X3. Turn ignition switch ªONº.
4. Check voltage between terminal 1 and ground with CONSULT-II or tester.
NEF228AVoltage: Approximately 5V
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness for open or short between ECM and intake air temperature sensor
©Repair harness or connectors.
Mass air flow sensor
harness connector
Air cleaner
DTC P0110 INTAKE AIR TEMPERATURE SENSORSR20DE
Diagnostic Procedure
EC-129