2001 NISSAN ALMERA N16 Mass air flow sensor

DescriptionNJEC0227SYSTEM DESCRIPTIONNJEC0227S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
EGR vol-
ume controlEGR volume control valve Camshaft position sensor (PHASE) Engine speed and cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Throttle position sensor Throttle position
Vehicle speed sensor Vehicle speed
Battery Battery voltage
Air conditioner switch Air conditioner operation
Power steering oil pressure switch Power steering load signal
Electrical load Electrical load signal
PNP switch Park/Neutral position signal
This system controls flow rate of EGR led from exhaust manifold
to intake manifold. The opening of the EGR by-pass passage in the
EGR volume control valve changes to control the flow rate. A
built-in step motor moves the valve in steps corresponding to the
ECM output pulses. The opening of the valve varies for optimum
engine control. The optimum value stored in the ECM is determined
by considering various engine conditions. The EGR volume control
valve remains close under the following conditions.
+Low engine coolant temperature
+Engine starting
+High-speed engine operation
+Extremely light load engine operation
+Engine idling
+Excessively high engine coolant temperature
+Wide open throttle
+Mass air flow sensor malfunction
+Low battery voltage
SEF551W
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG
Description
EC-285

DescriptionNJEC0504SYSTEM DESCRIPTIONNJEC0504S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
EGR vol-
ume controlEGR volume control valve Camshaft position sensor (PHASE) Engine speed and cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Throttle position sensor Throttle position
Vehicle speed sensor Vehicle speed
Battery Battery voltage
Air conditioner switch Air conditioner operation
Power steering oil pressure switch Power steering load signal
Electrical load Electrical load signal
PNP switch Park/Neutral position signal
This system controls flow rate of EGR led from exhaust manifold
to intake manifold. The opening of the EGR by-pass passage in the
EGR volume control valve changes to control the flow rate. A
built-in step motor moves the valve in steps corresponding to the
ECM output pulses. The opening of the valve varies for optimum
engine control. The optimum value stored in the ECM is determined
by considering various engine conditions. The EGR volume control
valve remains close under the following conditions.
+Low engine coolant temperature
+Engine starting
+High-speed engine operation
+Extremely light load engine operation
+Engine idling
+Excessively high engine coolant temperature
+Wide open throttle
+Mass air flow sensor malfunction
+Low battery voltage
SEF551W
DTC P0403 EGR VOLUME CONTROL VALVE (CIRCUIT)
(WHERE FITTED)
QG
Description
EC-293

2 CHECK EXHAUST AIR LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust air leak before the three way catalyst.
SEF099P
OK or NG
OK©GO TO 3.
NG©Repair or replace.
3 CHECK INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK©GO TO 4.
NG©Repair or replace.
4 CHECK IGNITION TIMING
Check for ignition timing.
Refer to ªBASIC INSPECTIONº, EC-98.
OK or NG
OK©GO TO 5.
NG©Check camshaft position sensor (PHASE) (EC-278) and crankshaft position sensor
(POS) (EC-272).
DTC P0420 THREE WAY CATALYST FUNCTIONQG
Diagnostic Procedure (Cont'd)
EC-301

DescriptionNJEC0248SYSTEM DESCRIPTIONNJEC0248S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
EVAP can-
ister purge
controlEVAP canister purge volume
control solenoid valve Camshaft position sensor (PHASE) Engine speed and cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Battery Battery voltage
Ignition switch Start signal
Closed throttle position switch* Closed throttle position
Throttle position sensor Throttle position
Heated oxygen sensor 1 (front)Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Fuel tank temperature sensor* Fuel temperature in fuel tank
Vehicle speed sensor Vehicle speed
*: If so equipped
This system controls flow rate of fuel vapor from the EVAP canis-
ter. The opening of the vapor by-pass passage in the EVAP canis-
ter purge volume control solenoid valve changes to control the flow
rate. The EVAP canister purge volume control solenoid valve
repeats ON/OFF operation according to the signal sent from the
ECM. The opening of the valve varies for optimum engine control.
The optimum value stored in the ECM is determined by consider-
ing various engine conditions. When the engine is operating, the
flow rate of fuel vapor from the EVAP canister is regulated as the
air flow changes.
SEF337U
COMPONENT DESCRIPTIONNJEC0248S02The EVAP canister purge volume control solenoid valve uses a
ON/OFF duty to control the flow rate of fuel vapor from the EVAP
canister. The EVAP canister purge volume control solenoid valve
is moved by ON/OFF pulses from the ECM. The longer the ON
pulse, the greater the amount of fuel vapor that will flow through the
valve.
CONSULT-II Reference Value in Data Monitor
Mode
NJEC0249
MONITOR ITEM CONDITION SPECIFICATION
PURG VOL C/V+Engine: After warming up
+No-loadIdle 0%
Revving engine Ð
DTC P0443 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
(CIRCUIT)
QG
Description
EC-304

DescriptionNJEC0349SYSTEM DESCRIPTIONNJEC0349S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
EGR vol-
ume controlEGR volume control valve Camshaft position sensor (PHASE) Engine speed and cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Throttle position sensor Throttle position
Vehicle speed sensor Vehicle speed
Battery Battery voltage
This system controls flow rate of EGR led from exhaust manifold
to intake manifold. The opening of the EGR by-pass passage in the
EGR volume control valve changes to control the flow rate. A
built-in step motor moves the valve in steps corresponding to the
ECM output pulses. The opening of the valve varies for optimum
engine control. The optimum value stored in the ECM is determined
by considering various engine conditions. The EGR volume control
valve remains close under the following conditions.
+Extremely light load engine operation
+Mass air flow sensor malfunction
+Engine idling
+Low engine coolant temperature
+Excessively high engine coolant temperature
+High-speed engine operation
+Wide open throttle
+Low battery voltage
+Engine starting
SEF551W
DTC P1402 EGR FUNCTION (OPEN) (WHERE FITTED)QG
Description
EC-353

SEC500C
Component DescriptionNJEC1737The 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)Voltage*
VResistance
kW
25 (77) 3.3 1.9 - 2.1
80 (176) 1.28 0.31 - 0.37
*: These data are reference values and are measured between ECM terminal 64
(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.
INTAKE AIR TEMPERATURE SENSORQG
Component Description
EC-369

Diagnostic ProcedureNJEC1739
1 CHECK OVERALL FUNCTION
1. Turn ignition switch ªONº.
2. Check voltage between ECM terminal 64 and ground with CONSULT-II or tester.
SEF004YA
OK or NG
OK©INSPECTION END
NG©GO TO 2.
2 CHECK POWER SUPPLY (Models with intake air temperature sensor in mass air flow sensor)
1. Turn ignition switch ªOFFº.
2. Disconnect mass air flow sensor harness connector.
JEF105Y
3. Turn ignition switch ªONº.
4. Check voltage between terminal 1 and ground with CONSULT-II or tester.
SEC503C
OK or NG
OK©GO TO 4.
NG©GO TO 3.
INTAKE AIR TEMPERATURE SENSORQG
Diagnostic Procedure
EC-371

3 DETECT MALFUNCTIONING PART
Check harness for open or short between ECM and intake air temperature sensor.
©Repair harness or connectors.
4 CHECK GROUND CIRCUIT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between mass air flow sensor harness connector terminal 3 and engine ground.
Refer to wiring diagram.
Continuity should exist.
3. 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 harness for open or short between ECM and intake air temperature sensor.
©Repair open circuit or short to ground or short to power in harness or connectors.
6 CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to ªComponent Inspectionº, EC-372.
OK or NG
OK©GO TO 7.
NG©Replace intake air temperature sensor.
7 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-144.
©INSPECTION END
SEC516C
Component InspectionNJEC1740INTAKE AIR TEMPERATURE SENSORNJEC1740S01Check resistance between mass air flow sensor harness connec-
tor terminals 3 and 5.

Intake air temperature
ÉC (ÉF)Resistance kW
25 (77) 1.9 - 2.1
If NG, replace intake air temperature sensor.
INTAKE AIR TEMPERATURE SENSORQG
Diagnostic Procedure (Cont'd)
EC-372