2001 NISSAN ALMERA engine

9 CHECK ECM POWER SUPPLY CIRCUIT-II
1. Stop engine.
2. Check voltage between ECM terminal 67 and ground with CONSULT-II or tester.
SEF293X
OK or NG
OK©GO TO 11.
NG©GO TO 10.
10 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E75, F36 (If so equipped)
+Harness for open or short between ECM and fuse
©Repair harness or connectors.
11 CHECK ECM POWER SUPPLY CIRCUIT-III
1. Turn ignition switch ªONº and then ªOFFº.
2. Check voltage between ECM terminals 110, 112 and ground with CONSULT-II or tester.
SEF294X
OK or NG
OK©GO TO 17.
NG (Battery voltage
does not exist.)©GO TO 12.
NG (Battery voltage
exists for more than a
few seconds.)©GO TO 14.
TROUBLE DIAGNOSIS FOR POWER SUPPLYQG
Main Power Supply and Ground Circuit (Cont'd)
EC-184

12 CHECK ECM POWER SUPPLY CIRCUIT-IV
1. Disconnect ECM relay. (For ECM relay location, refer to ªEngine Control Compartment Parts Locationº.)
2. Check voltage between ECM relay terminal 3 or 5 (only ECM relay in relay box) and ground with CONSULT-II or tester.
YEC048A
OK or NG
OK©GO TO 14.
NG©GO TO 13.
13 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E75, F36 (If so equipped)
+Harness for open or short between ECM relay and 10A fuse
©Repair open circuit or short to ground or short to power in harness or connectors.
14 CHECK HARNESS CONTINUITY BETWEEN ECM RELAY AND ECM FOR OPEN AND SHORT
1. Check harness continuity between ECM terminals 110, 112 and ECM relay terminal 5 or 3 (only ECM relay in relay
box).
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 16.
NG©GO TO 15.
15 DETECT MALFUNCTIONING PART
Check the following.
+Joint connector-4 (If so equipped)
+Joint connector-6 (If so equipped)
+Harness connector E75, F36 (If so equipped)
+Harness for open or short between ECM and ECM relay
©Repair open circuit or short to ground or short to power in harness or connectors.
TROUBLE DIAGNOSIS FOR POWER SUPPLYQG
Main Power Supply and Ground Circuit (Cont'd)
EC-185

16 CHECK ECM RELAY
1. Apply 12V direct current between ECM relay terminals 1 and 2.
2. Check continuity between relay terminals 3 and 5, 6 and 7.
SEF296X
OK or NG
OK©GO TO 17.
NG©Replace ECM relay.
17 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals 48, 57, 106, 108 and engine ground.
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 18.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
18 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-177.
©INSPECTION END
TROUBLE DIAGNOSIS FOR POWER SUPPLYQG
Main Power Supply and Ground Circuit (Cont'd)
EC-186

SEF987W
Component DescriptionNJEC0050The 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
NJEC0051Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
MAS A/F SE-B1+Engine: After warming up
+Air conditioner switch: ªOFFº
+Shift lever: ªNº
+No-loadIdle 1.0 - 1.7V
2,500 rpm 1.5 - 2.1V
MASS AIRFLOW+Engine: After warming up
+Air conditioner switch: ªOFFº
+Shift lever: ªNº
+No-loadIdle 1.0 - 4.0 g´m/s
2,500 rpm 5.0 - 10.0 g´m/s
ECM Terminals and Reference ValueNJEC0052Specification data are reference values and are measured between each terminal 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.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
61 G Mass air flow sensor[Engine is running]
+Warm-up condition
+Idle speed1.0 - 1.7V
[Engine is running]
+Warm-up condition
+Engine speed is 2,500 rpm1.5 - 2.1V
73 BMass air flow sensor
ground[Engine is running]
+Warm-up condition
+Idle speedApproximately 0V
On Board Diagnosis LogicNJEC0053
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.+Harness or connectors
(The sensor circuit is open or shorted.)
+Mass air flow sensor
B) An excessively low voltage from the sensor is sent
to ECM* when engine is running.+Harness or connectors
(The sensor circuit is open or shorted.)
+Intake air leaks
+Mass air flow sensor
*: When this malfunction is detected, the ECM enters fail-safe mode and the MI lights up.
DTC P0100 MASS AIR FLOW SENSOR (MAFS)QG
Component Description
EC-187

Fail-safe ModeNJEC0589
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 ProcedureNJEC0054CAUTION:
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.
SEF058Y
PROCEDURE FOR MALFUNCTION ANJEC0054S01With 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-191.
With GST
Follow the procedure ªWith CONSULT-IIº above.
SEF058Y
PROCEDURE FOR MALFUNCTION BNJEC0054S02With 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-191.
With GST
Follow the procedure ªWith CONSULT-IIº above.
DTC P0100 MASS AIR FLOW SENSOR (MAFS)QG
Fail-safe Mode
EC-188

Wiring DiagramNJEC0056SEDAN MODELS AND HATCHBACK MODELS WITH
ECM IN ENGINE COMPARTMENT
NJEC0056S01
HEC781
DTC P0100 MASS AIR FLOW SENSOR (MAFS)QG
Wiring Diagram
EC-189

Diagnostic ProcedureNJEC0057
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.
+Air duct
+Vacuum hoses
+Intake 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.
JEF104Y
©GO TO 4.
DTC P0100 MASS AIR FLOW SENSOR (MAFS)QG
Diagnostic Procedure
EC-191

7 CHECK INPUT SIGNAL CIRCUIT
1. Check harness continuity between mass air flow sensor harness connector terminal 1 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 8.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
8 CHECK MASS AIR FLOW SENSOR
Refer to ªComponent Inspectionº, EC-193.
OK or NG
OK©GO TO 9.
NG©Replace mass air flow sensor.
9 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-177.
©INSPECTION END
SEF993W
SEF987W
Component InspectionNJEC0058MASS AIR FLOW SENSORNJEC0058S011. 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.)1.0 - 1.7
2,500 rpm (Engine is warmed-up to normal oper-
ating temperature.)1.7 - 2.1
Idle to about 4,000 rpm* 1.0 - 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.
DTC P0100 MASS AIR FLOW SENSOR (MAFS)QG
Diagnostic Procedure (Cont'd)
EC-193