
DescriptionNLEC0248SYSTEM DESCRIPTIONNLEC0248S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
EVAP can-
ister purge
controlEVAP canister purge volume
control solenoid valve Camshaft position sensor (PHASE) Engine speed and cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Battery Battery voltage
Ignition switch Start signal
Closed throttle position switch Closed throttle position
Throttle position sensor Throttle position
Heated oxygen sensor 1 (front)Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Vehicle speed sensor Vehicle speed
This system controls flow rate of fuel vapor from the EVAP canis-
ter. The opening of the vapor by-pass passage in the EVAP canis-
ter purge volume control solenoid valve changes to control the flow
rate. The EVAP canister purge volume control solenoid valve
repeats ON/OFF operation according to the signal sent from the
ECM. The opening of the valve varies for optimum engine control.
The optimum value stored in the ECM is determined by consider-
ing various engine conditions. When the engine is operating, the
flow rate of fuel vapor from the EVAP canister is regulated as the
air flow changes.
SEF337U
COMPONENT DESCRIPTIONNLEC0248S02The EVAP canister purge volume control solenoid valve uses a
ON/OFF duty to control the flow rate of fuel vapor from the EVAP
canister. The EVAP canister purge volume control solenoid valve
is moved by ON/OFF pulses from the ECM. The longer the ON
pulse, the greater the amount of fuel vapor that will flow through the
valve.
CONSULT-II Reference Value in Data Monitor
Mode
NLEC0249
MONITOR ITEM CONDITION SPECIFICATION
PURG VOL C/V+Engine: After warming up
+No-loadIdle 0%
Revving engine Ð
DTC P0443 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
(CIRCUIT)
QG18DE
Description
EC-332

ECM Terminals and Reference Value=NLEC0250Specification 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)
14 GY/LEVAP canister purge vol-
ume control solenoid valve[Engine is running]
+Warm-up condition
+Idle speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
+Warm-up condition
+2,000 rpm5 - 12V
SEF975W
On Board Diagnosis LogicNLEC0251
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0443
0443+An improper voltage signal is sent to ECM through the
valve.+Harness or connectors
(The valve circuit is open or shorted.)
+EVAP canister purge volume control solenoid
valve
DTC Confirmation ProcedureNLEC0252NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 9 seconds
before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm battery
voltage is more than 11V.
SEF058Y
With CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and let it idle for at least 5 seconds.
4) If 1st trip DTC is detected, go to ªDIAGNOSTIC
PROCEDUREº, EC-336.
With GST
Follow the procedure ªWith CONSULT-IIº above.
DTC P0443 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
(CIRCUIT)
QG18DE
ECM Terminals and Reference Value
EC-333

DescriptionNLEC0279SYSTEM DESCRIPTIONNLEC0279S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
Idle air con-
trolIACV-AAC valve Camshaft position sensor (PHASE) Engine speed and cylinder number
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Throttle position sensor Throttle position
PNP switch Park/Neutral position
Air conditioner switch Air conditioner operation
Power steering oil pressure switch Power steering load signal
Battery Battery voltage
Vehicle speed sensor Vehicle speed
Cooling fan Cooling fan operation
Electrical load Electrical load signal
This system automatically controls engine idle speed to a specified
level. Idle speed is controlled through fine adjustment of the
amount of air which by-passes the throttle valve via IACV-AAC
valve. The IACV-AAC valve changes the opening of the air by-pass
passage to control the amount of auxiliary air. This valve is actu-
ated by a step motor built into the valve, which moves the valve in
the axial direction in steps corresponding to the ECM output sig-
nals. One step of IACV-AAC valve movement causes the respec-
tive opening of the air by-pass passage. (i.e. when the step
advances, the opening is enlarged.) The opening of the valve is
varied to allow for optimum control of the engine idling speed. The
crankshaft position sensor (POS) detects the actual engine speed
and sends a signal to the ECM. The ECM then controls the step
position of the IACV-AAC valve so that engine speed coincides with
the target value memorized in ECM. The target engine speed is the
lowest speed at which the engine can operate steadily. The opti-
mum value stored in the ECM is determined by taking into consid-
eration various engine conditions, such as during warm up,
deceleration, and engine load (air conditioner, power steering, cool-
ing fan operation and electrical load).
SEF937W
COMPONENT DESCRIPTIONNLEC0279S02IACV-AAC ValveNLEC0279S0202The IACV-AAC valve is operated by a step motor for centralized
control of auxiliary air supply. This motor has four winding phases
and is actuated by the output signals of ECM which turns ON and
OFF two windings each in sequence. Each time the IACV-AAC
valve opens or closes to change the auxiliary air quantity, the ECM
sends a pulse signal to the step motor. When no change in the
auxiliary air quantity is needed, the ECM does not issue the pulse
signal. A certain voltage signal is issued so that the valve remains
at that particular opening.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
QG18DE
Description
EC-343

SEF505V
Component DescriptionNLEC0287A closed throttle position switch and wide open throttle position
switch are built into the throttle position sensor unit. The wide open
throttle position switch is not used.
When the throttle valve is in the closed position, the closed throttle
position switch sends a voltage signal to the ECM. The ECM only
uses this signal to open or close the EVAP canister purge control
valve when the throttle position sensor is malfunctioning.
CONSULT-II Reference Value in Data Monitor
Mode
NLEC0571Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
CLSD THL/P SW+Engine: IdleThrottle valve: Idle position ON
Throttle valve: Slightly open OFF
ECM Terminals and Reference ValueNLEC0288Specification 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)
40 Y/PUThrottle position switch
(Closed position)[Engine is running]
+Accelerator pedal releasedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
+Accelerator pedal depressedApproximately 0V
On Board Diagnosis LogicNLEC0289
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0510
0510+Battery voltage from the closed throttle position switch is
sent to ECM with the throttle valve opened.+Harness or connectors
(The closed throttle position switch circuit is
shorted.)
+Closed throttle position switch
+Throttle position sensor
SEF197Y
DTC Confirmation ProcedureNLEC0290CAUTION:
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.
With CONSULT-II
1) Start engine and warm it up to normal operating temperature.
2) Turn ignition switch ªOFFº, wait at least 9 seconds and then
start engine.
DTC P0510 CLOSED THROTTLE POSITION SWITCH
(WHERE FITTED)
QG18DE
Component Description
EC-352

3) Select ªCLSD THL/P SWº in ªDATA MONITORº mode. If
ªCLSD THL/P SWº is not available, go to step 5.
4) Check the signal under the following conditions.
Condition Signal indication
Throttle valve: Idle position ON
Throttle valve: Slightly open OFF
If the result is NG, go to ªDiagnostic Procedureº, EC-355.
If OK, go to following step.
5) Select ªDATA MONITORº mode with CONSULT-II.
6) Drive the vehicle for at least 5 consecutive seconds under the
following condition.
THRTL POS SEN More than 2.3V
VHCL SPEED SE More than 4 km/h (2 MPH)
Selector lever Suitable position
Driving pattern Driving vehicle uphill (Increased engine load)
will help maintain the driving conditions
required for this test.
7) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-355.
SEF090X
Overall Function CheckNLEC0291Use this procedure to check the overall function of the closed
throttle position switch circuit. During this check, a 1st trip DTC
might not be confirmed.
Without CONSULT-II
1) Start engine and warm it up to normal operating temperature.
2) Check the voltage between ECM terminal 40 (Closed throttle
position switch signal) and ground under the following condi-
tions.
Condition Voltage
At idle Battery voltage
At 2,000 rpm Approximately 0V
3) If NG, go to ªDiagnostic Procedureº, EC-355.
DTC P0510 CLOSED THROTTLE POSITION SWITCH
(WHERE FITTED)
QG18DE
DTC Confirmation Procedure (Cont'd)
EC-353

Diagnostic ProcedureNLEC0293
1 CHECK POWER SUPPLY
1. Turn ignition switch ªOFFº.
2. Disconnect throttle position switch harness connector.
JEF091Y
3. Turn ignition switch ªONº.
4. Check voltage between terminal 5 and engine ground with CONSULT-II or tester.
SEF837X
Voltage: Battery voltage
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E75, F35
+10A fuse
+Harness for open or short between throttle position switch and fuse
©Repair harness or connectors.
3 CHECK INPUT SIGNAL CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 40 and terminal 4.
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.
DTC P0510 CLOSED THROTTLE POSITION SWITCH
(WHERE FITTED)
QG18DE
Diagnostic Procedure
EC-355

SEF095X
Component DescriptionNLEC0513The valve timing control system is utilized to control intake valve
opening and closing timing. Engine coolant temperature signals,
engine speed and throttle position are used to determine intake
valve timing.
The intake camshaft sprocket position is regulated by oil pressure
controlled by the intake valve timing control.
When ECM sends ON signal to intake valve timing control solenoid
valve, oil pressure is transmitted to camshaft sprocket. Then, intake
side camshaft is advanced.
OperationNLEC0514
Engine operating condition
Intake valve tim-
ing control sole-
noid valveIntake valve
opening and
closing timeValve overlap
Engine coolant
temperatureEngine speed B/FUEL SCHDL Neutral switch
20ÉC (68ÉF) -
70ÉC (158ÉF)
1,150 - 4,600
rpmAbove 3 msec
OFF ON Advance Increased
Above 70ÉC
(158ÉF)Above 7 msec
Conditions other than those above OFF Normal Normal
CONSULT-II Reference Value in Data Monitor
Mode
NLEC0515
MONITOR ITEM CONDITION SPECIFICATION
INT/V SOL-B1+Engine: After warming up
+Lift up vehicle and suitable gear
positionIdle OFF
Revving engine from 2,000 to
3,000 rpmON
ECM Terminals and Reference ValueNLEC0516Specification 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)
1 Y/RIntake valve timing control
solenoid valve[Engine is running]
+Idle speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
+Warm-up condition
+Lift up vehicle and suitable gear position
+Rev engine from 2,000 to 3,000 rpmApproximately 0V
On Board Diagnosis LogicNLEC0517
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P 1111
1111+An improper voltage signal is entered to ECM through
intake valve timing control solenoid valve.+Harness or connectors
(The intake valve timing control solenoid valve
circuit is open or shorted.)
+Intake valve timing control solenoid valve
D T C P 1111INTAKE VALVE TIMING CONTROL
SOLENOID VALVE
QG18DE
Component Description
EC-360

4 CHECK VALVE TIMING CONTROL SOLENOID VALVE
Refer to ªComponent Inspectionº, EC-365.
OK or NG
OK©GO TO 5.
NG©Replace valve timing control solenoid valve.
5 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-145.
©INSPECTION END
SEF159Y
Component InspectionNLEC0521INTAKE VALVE TIMING CONTROL SOLENOID VALVENLEC0521S011. Check oil passage visually for any metal debris.
2. Supply intake valve timing control solenoid valve terminals with
battery voltage.
3. Make sure that inside plunger protrudes.
If NG, replace intake valve timing control solenoid valve.
D T C P 1111INTAKE VALVE TIMING CONTROL
SOLENOID VALVE
QG18DE
Diagnostic Procedure (Cont'd)
EC-365