NISSAN ALMERA 2001 Service Manual

Component DescriptionNJEC0079NOTE:
If DTC P0120 (0120) is displayed with DTC P0510 (0510), first perform trouble diagnosis for DTC P0510,
EC-385.
The throttle position sensor responds to the accelerator pedal movement. This sensor is a kind of potentiom-
eter which transforms the throttle position into output voltage, and emits the voltage signal to the ECM. In
addition, the sensor detects the opening and closing speed of the throttle valve and feeds the voltage signal
to the ECM.
Idle position of the throttle valve is determined by the ECM receiving the signal from the throttle position sen-
sor. This sensor controls engine operation such as fuel cut. On the other hand, the ªWide open and closed
throttle position switchº, which is built into the throttle position sensor unit, is not used for engine control.
NEF308A
CONSULT-II Reference Value in Data Monitor
Mode
NJEC0080Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
THRTL POS SEN+Engine: Idle Throttle valve: fully closed 0.15 - 0.85V
+Ignition switch: ON
(Engine stopped)Throttle valve: fully opened 3.5 - 4.7V
ABSOL TH´P/S+Engine: Idle Throttle valve: fully closed 0.0É
+Ignition switch: ON
(Engine stopped)Throttle valve: fully opened Approx. 80É
DTC P0120 THROTTLE POSITION SENSORQG
Component Description
EC-207

ECM Terminals and Reference Value=NJEC0081Specification 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)
58 B Sensors' ground[Engine is running]
+Warm up condition
+Idle speedApproximately 0V
92 Y Throttle position sensor[Engine is running]
+Accelerator pedal fully released0.15 - 0.85V
[Ignition switch ªONº]
+Accelerator pedal fully depressed3.5 - 4.7V
111 R Sensors' power supply[Ignition switch ªONº]Approximately 5V
On Board Diagnosis LogicNJEC0082
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0120
0120An excessively low or high voltage from the sensor is
sent to ECM* while driving.+Harness or connectors
(The throttle position sensor circuit is open or
shorted.)
+Throttle position sensor
*: When this malfunction is detected, the ECM enters fail-safe mode and the MI lights up.
Fail-safe ModeNJEC0567
Detected items Engine operating condition in fail-safe mode
Throttle position sensor
circuitThrottle position will be determined based on the injected fuel amount and the engine speed.
Therefore, acceleration will be poor.
Condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration
DTC Confirmation ProcedureNJEC0083NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 9 seconds
before conducting the next test.
CAUTION:
Always drive vehicle at a safe speed.
TESTING CONDITION:
+Before performing the following procedure, confirm that
battery voltage is more than 10V at idle.
+This test may be conducted with the drive wheels lifted in
DTC P0120 THROTTLE POSITION SENSORQG
ECM Terminals and Reference Value
EC-208

the shop or by driving the vehicle. If a road test is
expected to be easier, it is unnecessary to lift the vehicle.
SEF175Y
With CONSULT-II
1) Turn ignition switch ªONº and select ªDATA MONITORº mode
with CONSULT-II.
2) Start engine and maintain the following conditions for at least
5 consecutive seconds.
VHCL SPEED SE More than 4 km/h (2 MPH)
Selector lever Suitable position except ªPº or ªNº
position
3) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-212.
With GST
Follow the procedure ªWith CONSULT-IIº above.
DTC P0120 THROTTLE POSITION SENSORQG
DTC Confirmation Procedure (Cont'd)
EC-209

Wiring DiagramNJEC0084SEDAN MODELS AND HATCHBACK MODELS WITH
ECM IN ENGINE COMPARTMENT
NJEC0084S01
HEC784
DTC P0120 THROTTLE POSITION SENSORQG
Wiring Diagram
EC-210

HATCHBACK MODELS WITH ECM IN CABINNJEC0084S02
HEC957
DTC P0120 THROTTLE POSITION SENSORQG
Wiring Diagram (Cont'd)
EC-211

Diagnostic ProcedureNJEC0085
1 RETIGHTEN GROUND SCREWS
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
JEF104Y
©GO TO 2.
2 CHECK POWER SUPPLY
1. Disconnect throttle position sensor harness connector.
NEF309A
2. Turn ignition switch ªONº.
3. Check voltage between terminal 3 and ground with CONSULT-II or tester.
SEF306X
OK or NG
OK©GO TO 4.
NG©GO TO 3.
DTC P0120 THROTTLE POSITION SENSORQG
Diagnostic Procedure
EC-212

3 DETECT MALFUNCTIONING PART
Check the following.
+Joint connector-4 (If so equipped)
+Joint connector (If so equipped)
+Harness for open or short between throttle position sensor terminal 3 and ECM terminal 111
©Repair harness or connectors.
4 CHECK GROUND CIRCUIT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between throttle position sensor harness connector terminal 1 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 the following.
+Joint connector-3 (If so equipped)
+Joint connector-6 (If so equipped)
+Harness for open or short between ECM terminal 58 and throttle position sensor
+Harness for open or short between ECM terminal 58 and TCM (Transmission Control Module)
©Repair open circuit or short to ground or short to power in harness or connectors.
6 CHECK INPUT SIGNAL CIRCUIT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 92 and throttle position sensor harness connector terminal 2.
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 7.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
7 CHECK THROTTLE POSITION SENSOR
Refer to ªComponent Inspectionº, EC-214.
OK or NG
OK©GO TO 8.
NG©Replace throttle position sensor. To adjust it, perform ªBasic Inspectionº, EC-100.
8 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-177.
©INSPECTION END
DTC P0120 THROTTLE POSITION SENSORQG
Diagnostic Procedure (Cont'd)
EC-213

SEF793W
SEF179Y
Component InspectionNJEC0086THROTTLE POSITION SENSORNJEC0086S01Models with Throttle OpenerNJEC0086S0101With CONSULT-II
1) Start engine and warm it up to normal operating temperature.
2) Stop engine (ignition switch OFF).
3) Remove the vacuum hose connected to the throttle opener.
4) Connect suitable vacuum hose to the vacuum pump and the
opener.
5) Apply vacuum [more than þ40.0 kPa (þ400 mbar, þ300 mmHg,
þ11.81 inHg)] until the throttle drum becomes free from the rod
of the throttle opener.
6) Turn ignition switch ON.
7) Select ªDATA MONITORº mode with CONSULT-II.
8) Check voltage of ªTHRTL POS SENº under the following con-
ditions.
NOTE:
Voltage measurement must be made with throttle position
sensor installed in vehicle.
Throttle valve conditions Voltage (V)
Completely closed 0.15 - 0.85 (a)
Partially open Between (a) and (b)
Completely open 3.5 - 4.7 (b)
If NG, adjust closed throttle position switch. Refer to ªBasic
Inspectionº, EC-100.
9) If it is impossible to adjust closed throttle position switch in
ªBasic Inspectionº, replace throttle position sensor.
SEF793W
SEF007X
Without CONSULT-II
1) Start engine and warm it up to normal operating temperature.
2) Stop engine (ignition switch OFF).
3) Remove the vacuum hose connected to the throttle opener.
4) Connect suitable vacuum hose to the vacuum pump and the
opener.
5) Apply vacuum [more than þ40.0 kPa (þ400 mbar, þ300 mmHg,
þ11.81 inHg)] until the throttle drum becomes free from the rod
of the throttle opener.
6) Turn ignition switch ON.
7) Check voltage between ECM terminal 92 (Throttle position
sensor signal) and ground under the following conditions.
NOTE:
Voltage measurement must be made with throttle position
sensor installed in vehicle.
Throttle valve conditions Voltage (V)
Completely closed 0.15 - 0.85 (a)
Partially open Between (a) and (b)
Completely open 3.5 - 4.7 (b)
DTC P0120 THROTTLE POSITION SENSORQG
Component Inspection
EC-214

If NG, adjust closed throttle position switch. Refer to ªBasic
Inspectionº, EC-100.
8) If it is impossible to adjust closed throttle position switch in
ªBasic Inspectionº, replace throttle position sensor.
NEF069A
Models without Throttle OpenerNJEC0086S0102With CONSULT-II
1) Stop engine (ignition switch OFF).
2) Turn ignition switch ON.
3) Select ªDATA MONITORº mode with CONSULT-II.
4) Check voltage of ªTHRTL POS SENº under the following con-
ditions.
NOTE:
Voltage measurement must be made with throttle position
sensor installed in vehicle.
Throttle valve conditions Voltage (V)
Completely closed 0.35 - 0.65 (a)
Partially open Between (a) and (b)
Completely open 3.7 - 4.5 (b)
If NG, adjust closed throttle position switch. Refer to ªBasic
Inspectionº, EC-100.
5) If it is impossible to adjust closed throttle position sensor idle
position in ªBasic Inspectionº, replace throttle position sensor.
SEF007X
Without CONSULT-II
1) Stop engine (ignition switch OFF).
2) Turn ignition switch ON.
3) Check voltage between ECM terminal 92 (Throttle position
sensor signal) and ground under the following conditions.
NOTE:
Voltage measurement must be made with throttle position
sensor installed in vehicle.
Throttle valve conditions Voltage (V)
Completely closed 0.35 - 0.65 (a)
Partially open Between (a) and (b)
Completely open 3.7 - 4.5 (b)
If NG, adjust throttle position sensor idle position. Refer to
ªBasic Inspectionº, EC-100.
4) If it is impossible to adjust throttle position sensor idle position
in ªBasic Inspectionº, replace throttle position sensor.
DTC P0120 THROTTLE POSITION SENSORQG
Component Inspection (Cont'd)
EC-215

SEF463R
SEF288D
Component DescriptionNJEC0094The heated oxygen sensor 1 (front) is placed into the exhaust
manifold. It detects the amount of oxygen in the exhaust gas com-
pared to the outside air. The heated oxygen sensor 1 (front) has a
closed-end tube made of ceramic zirconia. The zirconia generates
voltage from approximately 1V in richer conditions to 0V in leaner
conditions. The heated oxygen sensor 1 (front) signal is sent to the
ECM. The ECM adjusts the injection pulse duration to achieve the
ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical
change from 1V to 0V.
CONSULT-II Reference Value in Data Monitor
Mode
NJEC0095Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S1 (B1)
+Engine: After warming upMaintaining engine speed at 2,000
rpm0 - 0.3V¨Approx. 0.6 - 1.0V
HO2S1 MNTR
(B1)LEAN¨RICH
Changes more than 5 times during
10 seconds.
ECM Terminals and Reference ValueNJEC0096Specification 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)
62 WHeated oxygen sensor
1 (front)[Engine is running]
+After warming up to normal operating tempera-
ture and engine speed is 2,000 rpm0 - Approximately 1.0V
SEF008W
DTC P0130 HEATED OXYGEN SENSOR 1 (FRONT) (CIRCUIT)QG
Component Description
EC-216