Diagnostic ProcedureNJEC0077
1 CHECK POWER SUPPLY
1. Turn ignition switch ªOFFº.
2. Disconnect engine coolant temperature sensor harness connector.
SEF999W
3. Turn ignition switch ªONº.
4. Check voltage between terminal 1 and ground with CONSULT-II or tester.
SEF301X
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the harness for open or short between ECM and engine coolant temperature sensor.
©Repair harness or connectors.
3 CHECK GROUND CIRCUIT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between engine coolant temperature sensor harness connector terminal 2 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.
DTC P0115 ENGINE COOLANT TEMPERATURE SENSOR (ECTS)
(CIRCUIT)
QG
Diagnostic Procedure
EC-166
4 DETECT MALFUNCTIONING PART
Check the following.
+Joint connector-6
+Harness for open or short between ECM and engine coolant temperature sensor
+Harness for open or short between engine coolant temperature sensor and TCM (Transmission Control Module)
©Repair open circuit or short to ground or short to power in harness or connectors.
5 CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to ªComponent Inspectionº, EC-167.
OK or NG
OK©GO TO 6.
NG©Replace engine coolant temperature sensor.
6 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-144.
©INSPECTION END
SEF152P
SEF012P
Component InspectionNJEC0078ENGINE COOLANT TEMPERATURE SENSORNJEC0078S01Check resistance as shown in the figure.
Temperature ÉC (ÉF) Resistance kW
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
If NG, replace engine coolant temperature sensor.
DTC P0115 ENGINE COOLANT TEMPERATURE SENSOR (ECTS)
(CIRCUIT)
QG
Diagnostic Procedure (Cont'd)
EC-167
DescriptionNJEC0227SYSTEM DESCRIPTIONNJEC0227S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
EGR vol-
ume controlEGR volume control 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
Ignition switch Start signal
Throttle position sensor Throttle position
Vehicle speed sensor Vehicle speed
Battery Battery voltage
Air conditioner switch Air conditioner operation
Power steering oil pressure switch Power steering load signal
Electrical load Electrical load signal
PNP switch Park/Neutral position signal
This system controls flow rate of EGR led from exhaust manifold
to intake manifold. The opening of the EGR by-pass passage in the
EGR volume control valve changes to control the flow rate. A
built-in step motor moves the valve in steps corresponding to the
ECM output pulses. The opening of the valve varies for optimum
engine control. The optimum value stored in the ECM is determined
by considering various engine conditions. The EGR volume control
valve remains close under the following conditions.
+Low engine coolant temperature
+Engine starting
+High-speed engine operation
+Extremely light load engine operation
+Engine idling
+Excessively high engine coolant temperature
+Wide open throttle
+Mass air flow sensor malfunction
+Low battery voltage
SEF551W
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG
Description
EC-285
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0400
0400+No EGR flow is detected under conditions that call for
EGR.+Harness or connectors
(EGR volume control valve circuit is open or
shorted.)
+EGR volume control valve stuck closed
+Dead (Weak) battery
+EGR passage clogged
+EGR temperature sensor and circuit
+Exhaust gas leaks
SEF013Y
SEF845Y
SEF846Y
SEF235Y
DTC Confirmation ProcedureNJEC0229CAUTION:
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.
+P0400 will not be displayed at ªSELF-DIAG RESULTSº mode
with CONSULT-II even though DTC work support test result is
ªNGº.
TESTING CONDITION:
+Before performing the following procedure, confirm bat-
tery voltage is more than 10V at idle, then stop engine
immediately.
+For best result, perform the test at a temperature of 0ÉC
(32ÉF) or higher.
With CONSULT-II
1) Turn ignition switch ªOFFº and wait at least 9 seconds.
2) Turn ignition switch ªONº.
3) Check ªCOOLAN TEMP/Sº in ªDATA MONITORº mode with
CONSULT-II and confirm it is within the range listed below.
COOLAN TEMP/S: Less than 40ÉC (104ÉF)
If the value is out of range, park the vehicle in a cool place and
allow the engine temperature to stabilize. Do not attempt to
lower the engine coolant temperature with a fan or means
other than ambient air. Doing so may produce an inaccurate
diagnostic result.
4) Start engine and let it idle monitoring ªCOOLAN TEMP/Sº
value. When the ªCOOLAN TEMP/Sº value reaches 70ÉC
(158ÉF), immediately go to the next step.
5) Select ªEGR SYSTEM P0400º of ªEGR SYSTEMº in ªDTC
WORK SUPPORTº mode with CONSULT-II.
6) Touch ªSTARTº.
7) Accelerate vehicle to a speed of 40 km/h (25 MPH) once and
then stop vehicle with engine running.
If ªCOMPLETEDº appears on CONSULT-II screen, go to step
9.
If ªCOMPLETEDº does not appear on CONSULT-II screen, go
to the following step.
8) When the following conditions are met, ªTESTINGº will be dis-
played on the CONSULT-II screen. Maintain the conditions
until ªTESTINGº changes to ªCOMPLETEDº. (It will take
approximately 45 seconds or more.)
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG
On Board Diagnosis Logic (Cont'd)
EC-287
ENG SPEED Above 2,400 rpm
Vehicle speed Above 90 km/h (56 MPH)
B/FUEL SCHDL 4.0 - 8.0 msec
Selector lever 4th or 5th
If ªTESTINGº is not displayed after 5 minutes, retry from
step 2.
9) Make sure that ªOKº is displayed after touching ªSELF-DIAG
RESULTSº. If ªNGº is displayed, refer to ªDiagnostic
Procedureº, EC-290.
With GST
1) Turn ignition switch ªONº.
2) Check engine coolant temperature in MODE 1 with GST.
Engine coolant temperature: Less than 40ÉC (104ÉF)
If the value is out of range, park the vehicle in a cool place and
allow the engine temperature to stabilize. Do not attempt to
lower the engine coolant temperature with a fan or means
other than ambient air. Doing so may produce an inaccurate
diagnostic result.
3) Start engine and let it idle monitoring the value of ªCOOLAN
TEMP/Sº. When the engine coolant temperature reaches 70ÉC
(158ÉF), immediately go to the next step.
4) Maintain the following conditions for at least 1 minute.
Engine speed Above 2,400 rpm
Vehicle speed Above 90 km/h (56 MPH)
Selector lever 4th or 5th
5) Stop vehicle.
6) Turn ignition switch ªOFFº and wait at least 9 seconds, then
turn ªONº.
7) Repeat step 2 to 4.
8) Select ªMODE 3º with GST.
9) If DTC is detected, go to ªDIAGNOSTIC PROCEDUREº,
EC-290.
+When using GST, ªDTC CONFIRMATION PROCEDUREº
should be performed twice as much as when using CON-
SULT-II because GST cannot diaplay MODE 7 (1st trip
DTC) concerning this diagnosis. Therefore, using CON-
SULT-II is recommended.
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG
DTC Confirmation Procedure (Cont'd)
EC-288
DescriptionNJEC0504SYSTEM DESCRIPTIONNJEC0504S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
EGR vol-
ume controlEGR volume control 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
Ignition switch Start signal
Throttle position sensor Throttle position
Vehicle speed sensor Vehicle speed
Battery Battery voltage
Air conditioner switch Air conditioner operation
Power steering oil pressure switch Power steering load signal
Electrical load Electrical load signal
PNP switch Park/Neutral position signal
This system controls flow rate of EGR led from exhaust manifold
to intake manifold. The opening of the EGR by-pass passage in the
EGR volume control valve changes to control the flow rate. A
built-in step motor moves the valve in steps corresponding to the
ECM output pulses. The opening of the valve varies for optimum
engine control. The optimum value stored in the ECM is determined
by considering various engine conditions. The EGR volume control
valve remains close under the following conditions.
+Low engine coolant temperature
+Engine starting
+High-speed engine operation
+Extremely light load engine operation
+Engine idling
+Excessively high engine coolant temperature
+Wide open throttle
+Mass air flow sensor malfunction
+Low battery voltage
SEF551W
DTC P0403 EGR VOLUME CONTROL VALVE (CIRCUIT)
(WHERE FITTED)
QG
Description
EC-293
DescriptionNJEC0248SYSTEM DESCRIPTIONNJEC0248S01
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)
Fuel tank temperature sensor* Fuel temperature in fuel tank
Vehicle speed sensor Vehicle speed
*: If so equipped
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 DESCRIPTIONNJEC0248S02The 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
NJEC0249
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)
QG
Description
EC-304
DescriptionNJEC0279SYSTEM DESCRIPTIONNJEC0279S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
Idle air
controlIACV-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 DESCRIPTIONNJEC0279S02IACV-AAC ValveNJEC0279S0202The 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
QG
Description
EC-313