2001 NISSAN PICK-UP Repair Manual

DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0101
0101B) A low voltage from the sensor is sent to ECM* under
heavy load driving condition.+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.
FAIL-SAFE MODENEEC0053S01
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 ProcedureNEEC0054CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch OFF and wait at least 5 seconds before
conducting the next test.
SEF174Y
PROCEDURE FOR MALFUNCTION ANEEC0054S03NOTE:
If engine will not start or stops soon, wait at least 10 seconds
with engine stopped (Ignition switch ªONº) instead of running
engine at idle speed.
With CONSULT-II
1) Turn ignition switch ON.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and warm it up to normal operating temperature.
4) Run engine for at least 10 seconds at idle speed.
5) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-3147.
With GST
Follow the procedure ªWith CONSULT-IIº.
DTC P0101 MAF SENSORKA24DE (EURO OBD)
On Board Diagnosis Logic
EC-3144

SEF243Y
SEF175Y
PROCEDURE FOR MALFUNCTION BNEEC0054S04With CONSULT-II
1) Turn ignition switch ON.
2) Start engine and warm it up to normal operating temperature.
If engine cannot be started, go to ªDiagnostic Procedureº,
EC-3147.
3) Select ªDATA MONITORº mode with CONSULT-II.
4) Check the voltage of ªMAS A/F SE-B1º with ªDATA MONITORº.
5) Increases engine speed to about 4,000 rpm.
6) Monitor the linear voltage rise in response to engine speed
increases.
If NG, go to ªDiagnostic Procedureº, EC-3147.
If OK, go to following step.
7) Maintain the following conditions for at least 10 consecutive
seconds.
ENG SPEED More than 2,000 rpm
THRTL POS SEN More than 3V
Selector lever Suitable position
Driving location Driving vehicle uphill (Increased engine load)
will help maintain the driving conditions
required for this test.
8) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-3147.
SEF534P
Overall Function CheckNEEC0055Use this procedure to check the overall function of the mass air flow
sensor circuit. During this check, a 1st trip DTC might not be con-
firmed.
PROCEDURE FOR MALFUNCTION BNEEC0055S01With GST
1) Turn ignition switch ON.
2) Start engine and warm it up to normal operating temperature.
3) Select ªMODE 1º with GST.
4) Check the mass air flow sensor signal with ªMODE 1º.
5) Check for linear mass air flow rise in response to increases to
about 4,000 rpm in engine speed.
6) If NG, go to ªDiagnostic Procedureº, EC-3147.
DTC P0101 MAF SENSORKA24DE (EURO OBD)
DTC Confirmation Procedure
EC-3145

Wiring DiagramNEEC0056
GEC237A
DTC P0101 MAF SENSORKA24DE (EURO OBD)
Wiring Diagram
EC-3146

Diagnostic ProcedureNEEC0057
1 INSPECTION START
Which malfunction (A, B, C or D) is duplicated?
MTBL1305
Type I or Type II
Type I©GO TO 3.
Type II©GO TO 2.
2 CHECK INTAKE SYSTEM
Check the followings for connection.
+Air duct
+Air cleaner
+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 OFF.
2. Loosen and retighten engine ground screws.
SEC309D
©GO TO 4.
DTC P0101 MAF SENSORKA24DE (EURO OBD)
Diagnostic Procedure
EC-3147

4 CHECK POWER SUPPLY
1. Disconnect mass air flow sensor harness connector.
AEC131A
2. Turn ignition switch ON.
3. Check voltage between terminal 3 and ground with CONSULT-II or tester.
AEC691
Voltage: Battery voltage
OK or NG
OK©GO TO 6.
NG©GO TO 5.
5 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E101, M5
+Harness for open or short between ECM relay and mass air flow sensor
+Harness for open or short between mass air flow sensor and ECM
©Repair harness or connectors.
6 CHECK GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between mass air flow sensor terminal 2 and ECM terminal 55. Refer to wiring diagram.
Continuity should exist.
4. Also check harness for short to ground or short to power.
OK or NG
OK©GO TO 7.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
DTC P0101 MAF SENSORKA24DE (EURO OBD)
Diagnostic Procedure
EC-3148

7 CHECK INPUT SIGNAL CIRCUIT
1. Check harness continuity between terminal 1 and ECM terminal 54. 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
1. Reconnect all harness connectors disconnected.
2. Turn ignition switch ON.
3. Start engine and warm it up to normal operating temperature.
4. Check voltage between ECM terminal 54 (mass air flow sensor signal) and ground.
SEF326V
MTBL0326
5. If the voltage is out of specification, disconnect mass air flow sensor harness connector and connect it again. Repeat
above check.
6. If NG, remove mass air flow sensor from air duct. Check hot wire for damage or dust.
SEF893J
OK or NG
OK©GO TO 9.
NG©Replace mass air flow sensor.
DTC P0101 MAF SENSORKA24DE (EURO OBD)
Diagnostic Procedure
EC-3149

9 CHECK SHIELD CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect joint connector-3.
3. Check the following.
+Continuity between joint connector-3 terminal 2 and ground
+Joint connector-3
(Refer to ªHARNESS LAYOUTº, in EL section.)
Continuity should exist.
4. Also check harness for short to power.
OK or NG
OK©GO TO 10.
NG©Repair open circuit or short to power in harness or connectors.
10 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-3123.
©INSPECTION END
DTC P0101 MAF SENSORKA24DE (EURO OBD)
Diagnostic Procedure
EC-3150

SEF893J
Component DescriptionNEEC1548The 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
NEEC1549Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
MAS A/F SE-B1+Engine: After warming up
+Air conditioner switch: OFF
+Shift lever: ªNº
+No-loadIdle 0.9 - 1.8V
2,500 rpm 1.9 - 2.3V
CAL/LD VALUE+Engine: After warming up
+Air conditioner switch: OFF
+Shift lever: ªNº
+No-loadIdle 9.5 - 34.0%
2,500 rpm 13.9 - 24.9%
MASS AIRFLOW+Engine: After warming up
+Air conditioner switch: OFF
+Shift lever: ªNº
+No-loadIdle 0.9 - 5.8 g´m/s
2,500 rpm 7.5 - 13.2 g´m/s
ECM Terminals and Reference ValueNEEC1550Specification 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)
54 L Mass air flow sensor[Engine is running]
+Warm-up condition
+Idle speed0.9 - 1.8V
[Engine is running]
+Warm-up condition
+Engine speed is 2,500 rpm1.9 - 2.3V
55 PMass air flow sensor
ground[Engine is running]
+Warm-up condition
+Idle speedApproximately 0V
On Board Diagnosis LogicNEEC1551
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0103
0103An excessively high voltage from the sensor is sent to
ECM.+Harness or connectors
(The sensor circuit is open or shorted.)
+Mass air flow sensor
DTC P0102, P0103 MAF SENSORKA24DE (EURO OBD)
Component Description
EC-3151