Page 937 of 2267

Component DescriptionNCEC0079NOTE:
If DTC P0120 (0120) is displayed with DTC P0510 (0510), first perform trouble diagnosis for DTC P0510,
EC-SR-271.
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.
CONSULT-II Reference Value in Data Monitor
Mode
NCEC0080Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
THRTL POS SENIEngine is idling. Throttle valve: fully closed 0.35 - 0.65V
IIgnition switch: ON
(Engine stopped)Throttle valve: fully opened 3.5 - 4.5V
ABSOL TH×P/SIEngine: Idle the engine Throttle valve: fully closed 0.0É
IIgnition switch: ON
(Engine stopped)Throttle valve: fully opened Approx. 80É
YEC118A
DTC P0120 THROTTLE POSITION SENSORSR20DE
Component Description
EC-137
Page 938 of 2267

ECM Terminals and Reference Value=NCEC0081Specification data are reference values and are measured between each terminal and 48 (ECM ground).
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
58 B Sensors' ground[Engine is running]
IWarm up condition
IIdle speedApproximately 0V
92 Y Throttle position sensor[Engine is running]
IAccelerator pedal fully released0.35 - 0.65V
[Ignition switch ªONº]
IAccelerator pedal fully depressedApproximately 4.0V
111 G Sensors' power supply[Ignition switch ªONº]Approximately 5V
On Board Diagnosis LogicNCEC0082
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*.IHarness or connectors
(The throttle position sensor circuit is open or
shorted.)
IThrottle position sensor
*: When this malfunction is detected, the ECM enters fail-safe mode and the MI lights up.
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 ProcedureNCEC0083NOTE:
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:
IBefore performing the following procedure, confirm that
battery voltage is more than 10V at idle.
IThis test may be conducted with the drive wheels lifted in
the shop or by driving the vehicle. If a road test is
expected to be easier, it is unnecessary to lift the vehicle.
DTC P0120 THROTTLE POSITION SENSORSR20DE
ECM Terminals and Reference Value
EC-138
Page 939 of 2267
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-
SR-141.
With GST
Follow the procedure ªWith CONSULT-IIº above.
PEF651U
DTC P0120 THROTTLE POSITION SENSORSR20DE
DTC Confirmation Procedure (Cont'd)
EC-139
Page 940 of 2267
Wiring DiagramNCEC0084
YEC083A
DTC P0120 THROTTLE POSITION SENSORSR20DE
Wiring Diagram
EC-140
Page 941 of 2267
Diagnostic ProcedureNCEC0085
1 RETIGHTEN GROUND SCREWS
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
SEF202X
©GO TO 2.
2 CHECK POWER SUPPLY
1. Disconnect throttle position sensor harness connector.
SEF197X2. Turn ignition switch ªONº.
3. Check voltage between terminal 3 and ground with CONSULT-II or tester.
SEF209WVoltage: Approximately 5V
OK or NG
OK©GO TO 3.
NG©Repair harness or connectors.
3 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 5.
NG©GO TO 4.
Intake manifold
collector
Engine
ground
Throttle position
sensor harness
connector Throttle body
Closed throttle position switch
harness connector (CVT
models)
DTC P0120 THROTTLE POSITION SENSORSR20DE
Diagnostic Procedure
EC-141
Page 942 of 2267

Component InspectionNCEC0086THROTTLE POSITION SENSORNCEC0086S01With CONSULT-II
1) Start engine and warm it up to normal operating temperature.
2) Stop engine (ignition switch OFF).
3) Turn ignition switch ON.
4) Select ªDATA MONITORº mode with CONSULT-II.
5) 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 closed0.35 - 0.65 (a)
Partially openBetween (a) and (b)
Completely open3.5 - 4.5 (b)
If NG, adjust throttle position sensor idle position. Refer to
ªBasic Inspectionº, EC-SR-84.
4 DETECT MALFUNCTIONING PART
Check the following.
IHarness for open or short between ECM and throttle position sensor
IHarness for open or short between throttle position sensor and TCM (Transmission control module)
©Repair open circuit or short to ground or short to power in harness or connectors.
5 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 6.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
6 CHECK THROTTLE POSITION SENSOR
Refer to ªComponent Inspectionº, EC-SR-142.
OK or NG
OK©GO TO 7.
NG©Replace throttle position sensor. To adjust it, perform ªBasic Inspectionº, EC-SR-84.
7 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-SR-114.
©INSPECTION END
NEF069A
DTC P0120 THROTTLE POSITION SENSORSR20DE
Component Inspection
EC-142
Page 943 of 2267
6) If it is impossible to adjust throttle position sensor idle position
in ªBasic Inspectionº, replace throttle position sensor.
Without CONSULT-II
1) Start engine and warm it up to normal operating temperature.
2) Stop engine (ignition switch OFF).
3) Turn ignition switch ON.
4) 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 closed0.35 - 0.65 (a)
Partially openBetween (a) and (b)
Completely openApprox. 4.0 (b)
If NG, adjust throttle position sensor idle position. Refer to
ªBasic Inspectionº, EC-SR-84.
5) If it is impossible to adjust throttle position sensor idle position
in ªBasic Inspectionº, replace throttle position sensor.
SEF007X
DTC P0120 THROTTLE POSITION SENSORSR20DE
Component Inspection (Cont'd)
EC-143
Page 944 of 2267

Component DescriptionNCEC0094The 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
NCEC0095Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S1 (B1)
IEngine: 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 ValueNCEC0096Specification data are reference values and are measured between each terminal and 48 (ECM ground).
TERMI-
NAL NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
62 RHeated oxygen sensor
1 (front)[Engine is running]
IAfter warming up to normal operating tempera-
ture and engine speed is 2,000 rpm0 - Approximately 1.0V
SEF008W
SEF463R
SEF288D
DTC P0130 HEATED OXYGEN SENSOR 1
(FRONT) (CIRCUIT)SR20DE
Component Description
EC-144