2001 NISSAN ALMERA ignition

Main Power Supply and Ground Circuit
ECM TERMINALS AND REFERENCE VALUENJEC0639Remarks: Specification 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.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA(DC Voltage)
104
105
106B
B
BECM ground[Engine is running]
+Idle speedApproximately 0V
107
108
109R
R
RPower supply for ECM[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
325 G ECM relay (Self-shutoff)[Ignition switch ªONº]
[Ignition switch ªOFFº]
+For a few seconds after turning ignition switch
ªOFFºApproximatley 0.25V
[Ignition switch ªOFFº]
+A few seconds passed after turning ignition
switch ªOFFºBATTERY VOLTAGE
(11 - 14V)
507 W/R Ignition switch[Ignition switch ªOFFº]0V
[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
TROUBLE DIAGNOSIS FOR POWER SUPPLYYD
Main Power Supply and Ground Circuit
EC-666

DIAGNOSTIC PROCEDURENJEC0641
1 INSPECTION START
Start engine.
Is engine running?
YesorNo
Ye s©GO TO 13.
No©GO TO 2.
2 CHECK ECM POWER SUPPLY CIRCUIT-I
1. Turn ignition switch ªONº.
2. Check voltage between ECM terminal 507 and ground with CONSULT-II or tester.
SEF895Y
OK or NG
OK©GO TO 4.
NG©GO TO 3.
3 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors M21, E106 or M160, E175 (Sedan models and hatchback models with ECM in engine compart-
ment)
+Harness connectors E75, F36 (Sedan models and hatchback models with ECM in engine compartment)
+Harness connectors M74, F112 (Hatchback models with ECM in cabin)
+Fuse block (J/B) connector M1
+10A fuse
+Harness for open or short between ECM and fuse
©Repair open circuit or short to ground or short to power in harness or connectors.
4 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals 104, 105, 106 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 5.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
TROUBLE DIAGNOSIS FOR POWER SUPPLYYD
Main Power Supply and Ground Circuit (Cont'd)
EC-669

5 CHECK ECM POWER SUPPLY CIRCUIT-II
1. Reconnect ECM harness connector.
2. Turn ignition switch ªONº and then ªOFFº.
3. Check voltage between ECM terminals 107, 108, 109 and ground with CONSULT-II or tester.
SEF896Y
OK or NG
OK©Check electronic control fuel injection pump power supply circuit. Refer to ªDiagnostic
Procedureº, EC-790.
NG (Battery voltage
does not exist.)©GO TO 6.
NG (Battery voltage
exists for more than a
few seconds.)©GO TO 10.
6 CHECK ECM POWER SUPPLY CIRCUIT-III
1. Disconnect ECM relay. (For ECM relay location, refer to ªEngine Control Component Parts Locationº.)
2. Check voltage between relay terminals 1, 6 and ground with CONSULT-II or tester.
SEF399Y
OK or NG
OK©GO TO 8.
NG©GO TO 7.
7 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E75, F36 (Sedan models and hatchback models with ECM in engine compartment)
+20A fuse
+Harness for open or short between ECM relay and battery
©Repair open circuit or short to ground or short to power in harness or connectors.
TROUBLE DIAGNOSIS FOR POWER SUPPLYYD
Main Power Supply and Ground Circuit (Cont'd)
EC-670

13 CHECK ECM POWER SUPPLY CIRCUIT-V
1. Turn ignition switch ªOFFº.
2. Disconnect ECM relay. (For ECM relay location, refer to ªEngine Control Component Parts Locationº.)
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM terminals 107, 108, 109 and ECM relay terminal 7. Refer to Wiring Diagram.
Continuity should exist.
5. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 15.
NG©GO TO 14.
14 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E75, F36 (New H/B)
+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.
15 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminals 104, 105, 106 and engine ground. 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©Repair open circuit or short to ground or short to power in harness or connectors.
16 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-665.
©INSPECTION END
TROUBLE DIAGNOSIS FOR POWER SUPPLYYD
Main Power Supply and Ground Circuit (Cont'd)
EC-672

SEF987W
Component DescriptionNJEC0642The mass air flow sensor (MAFS) is placed in the stream of intake
air. It measures the intake air flow rate by measuring a part of the
entire intake air flow. It consists of a hot film that is supplied with
electric current from the ECM. The temperature of the hot film is
controlled by the ECM a certain amount. The heat generated by the
hot film 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 film as air flow increases. The ECM
detects the air flow by means of this current change.
CONSULT-II Reference Value in Data Monitor
Mode
NJEC0643Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
MAS AIR/FL SE+Engine: After warming up
+Air conditioner switch: ªOFFº
+Shift lever: Neutral position
+No-loadIdle 1.5 - 2.0V
ECM Terminals and Reference ValueNJEC0644Specification 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)
218 B Sensor's ground[Engine is running]
+Warm-up condition
+Idle speedApproximately 0V
223 WMass air flow sensor
power supply[Ignition switch ªONº]Approximately 5V
224 R Mass air flow sensor[Engine is running]
+Warm-up condition
+Idle speed1.5 - 2.0V
On Board Diagnosis LogicNJEC0645
DTC Malfunction is detected when ... Check Items (Possible Cause)
P0100
0102+An excessively high or low voltage from the sen-
sor is sent to ECM.+Harness or connectors
(The sensor circuit is open or shorted.)
+Mass air flow sensor
SEF817Y
DTC Confirmation ProcedureNJEC0646WITH CONSULT-IINJEC0646S011) Turn ignition switch ªONº, and wait at least 6 seconds.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and wait at least 3 seconds.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-677.
WITHOUT CONSULT-IINJEC0646S021) Turn ignition switch ªONº, and wait at least 6 seconds.
2) Start engine and wait at least 3 seconds.
DTC P0100 MASS AIR FLOW SENYD
Component Description
EC-673

3) Turn ignition switch ªOFFº, wait at least 5 seconds and then
turn ªONº.
4) Perform ªDiagnostic Test Mode II (Self-diagnostic results)º with
ECM.
5) If DTC is detected, go to ªDiagnostic Procedureº, EC-677.
DTC P0100 MASS AIR FLOW SENYD
DTC Confirmation Procedure (Cont'd)
EC-674

Diagnostic ProcedureNJEC0648
1 CHECK MAFS POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect mass air flow sensor harness connector.
SEF884Y
3. Turn ignition switch ªONº.
4. Check voltage between mass air flow sensor terminals 2, 4 and ground with CONSULT-II or tester.
SEF297X
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E75, F36 (Sedan models and hatchback models with ecm in engine compartment)
+Harness for open or short between mass air flow sensor and ECM
+Harness for open or short between mass air flow sensor and ECM relay
©Repair open circuit or short to ground or short to power in harness or connector.
DTC P0100 MASS AIR FLOW SENYD
Diagnostic Procedure
EC-677

3 CHECK MAFS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
SEF380Y
3. Check harness continuity between mass air flow sensor terminal 3 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 5.
NG©GO TO 4.
4 DETECT MALFUNCTIONING PART
Check harness for open or short between mass air flow sensor and ECM.
©Repair open circuit or short to ground or short to power in harness or connectors.
5 CHECK MAFS INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between mass air flow sensor terminal 1 and ECM terminal 224. 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©Repair open circuit or short to ground or short to power in harness or connectors.
DTC P0100 MASS AIR FLOW SENYD
Diagnostic Procedure (Cont'd)
EC-678