Page 689 of 2267

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 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-QG-249.
IWhen using GST, ªDTC CONFIRMATION PROCEDUREº
should be performed twice as much as when using CON-
SULT-II or ECM (Diagnostic Test Mode II) because GST
cannot display MODE 7 (1st trip DTC) concerning this
diagnosis. Therefore, using CONSULT-II or ECM (Diagnos-
tic Test Mode II) is recommended.
DTC P0400 EGR FUNCTION (CLOSE) (IF SO EQUIPPED)QG16I18DE
DTC Confirmation Procedure (Cont'd)
EC-247
Page 690 of 2267
Wiring DiagramNCEC0231
YEC072A
DTC P0400 EGR FUNCTION (CLOSE) (IF SO EQUIPPED)QG16I18DE
Wiring Diagram
EC-248
Page 691 of 2267
Diagnostic ProcedureNCEC0232
1 CHECK EXHAUST SYSTEM
1. Start engine.
2. Check exhaust pipes and muffler for leaks.
SEF099P
OK or NG
OK (With CONSULT-II)©GO TO 2.
OK (Without CONSULT-II)©GO TO 3.
NG©Repair or replace exhaust system.
2 CHECK POWER SUPPLY
1. Disconnect EGR volume control valve harness connector.
2. Turn ignition switch ªONº.
3. Check voltage between terminals 2, 5 and ground with CONSULT-II or tester.
DISCONNECT
SEF556WAVoltage: Battery voltage
OK or NG
OK©GO TO 3.
NG©Check the following.
IHarness or connectors E90, F73
IHarness for open or short between EGR volume control valve and engine control
module relay
If NG, repair harness or connectors.
DTC P0400 EGR FUNCTION (CLOSE) (IF SO EQUIPPED)QG16I18DE
Diagnostic Procedure
EC-249
Page 692 of 2267

3 CHECK OUTPUT SIGNAL CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between
ECM terminal 8 and EGR volume control valve terminal 1,
ECM terminal 9 and EGR volume control valve terminal 4,
ECM terminal 17 and EGR volume control valve terminal 3,
ECM terminal 18 and EGR volume control valve terminal 6.
Refer to wiring diagram.
Continuity should exist.
If OK, check harness for short to ground and short to power.
OK or NG
OK©GO TO 4.
NG©Repair open circuit, short to ground or short to power in harness connectors.
4 CHECK EGR PASSAGE
Check EGR passage for clogging and cracks.
OK or NG
OK©GO TO 5.
NG©Repair or replace EGR passage.
5 CHECK EGR TEMPERATURE SENSOR
Refer to ªTROUBLE DIAGNOSIS FOR DTC P1401º, EC-QG-300.
OK or NG
OK©GO TO 6.
NG©Replace EGR temperature sensor.
6 CHECK EGR VOLUME CONTROL VALVE
Refer to ªComponent Inspectionº, EC-QG-251.
OK or NG
OK©GO TO 7.
NG©Replace EGR volume control valve.
7 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-QG-102.
©INSPECTION END
DTC P0400 EGR FUNCTION (CLOSE) (IF SO EQUIPPED)QG16I18DE
Diagnostic Procedure (Cont'd)
EC-250
Page 693 of 2267

Component InspectionNCEC0233EGR VOLUME CONTROL VALVENCEC0233S01With CONSULT-II
1) Disconnect EGR volume control valve harness connector.
2) Check resistance between the following terminals.
terminal 2 and terminals 1, 3
terminal 5 and terminals 4, 6
Temperature ÉC (ÉF) ResistanceW
20 (68) 20 - 24
3) Reconnect EGR volume control valve harness connector.
4) Remove EGR volume control valve from cylinder head.
(The EGR volume control valve harness connector should
remain connected.)
5) Turn ignition switch ªONº.
6) Perform ªEGR VOL CONT/Vº in ªACTIVE TESTº mode with
CONSULT-II. Check that EGR volume control valve shaft
moves smoothly forward and backward according to the valve
opening.
If NG, replace the EGR volume control valve.
Without CONSULT-II
1) Disconnect EGR volume control valve harness connector.
2) Check resistance between the following terminals.
terminal 2 and terminals 1, 3
terminal 5 and terminals 4, 6
Temperature ÉC (ÉF) ResistanceW
20 (68) 20 - 24
3) Turn ignition switch ªONº and ªOFFº. Check that EGR volume
control valve shaft moves smoothly forward and backward
according to the ignition switch position.
If NG, replace the EGR volume control valve.
SEF069X
SEF558W
NEF109A
SEF560W
DTC P0400 EGR FUNCTION (CLOSE) (IF SO EQUIPPED)QG16I18DE
Component Inspection
EC-251
Page 694 of 2267

DescriptionNCEC0504SYSTEM DESCRIPTIONNCEC0504S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor Engine speed
EGR control EGR volume control valve 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 or ABS actuator and
electric unit (control unit)Vehicle speed
Battery Battery voltage
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 closed under the following conditions.
ILow engine coolant temperature
IEngine starting
IHigh-speed engine operation
IExtremely light load engine operation
IEngine idling
IExcessively high engine coolant temperature
IWide open throttle
IMass air flow sensor malfunction
ILow battery voltage
COMPONENT DESCRIPTIONNCEC0504S02The EGR volume control valve uses a step motor to control the flow
rate of EGR from exhaust manifold. This motor has four winding
phases. It operates according to the output pulse signal of the
ECM. Two windings are turned ON and OFF in sequence. Each
time an ON pulse is issued, the valve opens or closes, changing
the flow rate. When no change in the flow rate 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.
SEF551W
SEF552W
DTC P0403 EGR VOLUME CONTROL VALVE (CIRCUIT)
(IF SO EQUIPPED)QG16I18DE
Description
EC-252
Page 695 of 2267

CONSULT-II Reference Value in Data Monitor
Mode
NCEC0506Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
EGR VOL CON/VIEngine: After warming up
IShift lever: ªNº
INo-loadIdle 0 step
Revving engine up to 3,000 rpm
quickly10 - 55 step
ECM Terminals and Reference ValueNCEC0507Specification 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 damage 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)
8
9
17
18W/B
SB
G/R
R/YEGR volume control valve[Engine is running]
IWarm-up condition
IRev engine up from 2,000 to 4,000 rpm0 - 14V
On Board Diagnosis LogicNCEC0508
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0403
0403IAn improper voltage signal is sent to ECM through the
valve.IHarness or connectors
(The EGR volume control valve circuit is open or
shorted.)
IEGR volume control valve
DTC Confirmation ProcedureNCEC0509NOTE:
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) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and warm it up to normal operating temperature.
4) Rev engine from idle to 2,000 rpm 20 times.
NEF110A
DTC P0403 EGR VOLUME CONTROL VALVE (CIRCUIT)
(IF SO EQUIPPED)QG16I18DE
CONSULT-II Reference Value in Data Monitor Mode
EC-253
Page 696 of 2267
If 1st trip DTC is detected, go to ªDiagnostic Procedureº, EC-
QG-256.
With GST
Follow the procedure ªWith CONSULT-IIº above.
DTC P0403 EGR VOLUME CONTROL VALVE (CIRCUIT)
(IF SO EQUIPPED)QG16I18DE
DTC Confirmation Procedure (Cont'd)
EC-254