Page 745 of 2267

Diagnostic ProcedureNCEC0347
1 CHECK POWER SUPPLY
1. Turn ignition switch ªOFFº.
2. Disconnect EGR temperature sensor harness connector.
SEF127X3. Turn ignition switch ªONº.
4. Check voltage between terminal 2 and ground with CONSULT-II or tester.
SEF128XVoltage: Approximately 5V
OK or NG
OK©GO TO 2.
NG©Repair harness or connectors.
2 CHECK GROUND CIRCUIT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between EGR temperature sensor harness 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 4.
NG©GO TO 3.
3 DETECT MALFUNCTIONING PART
Check the harness for open or short between EGR temperature sensor and ECM.
©Repair open circuit or short to ground or short to power in harness or connector.
4 CHECK EGR TEMPERATURE SENSOR
Refer to ªComponent Inspectionº, EC-QG-304.
OK or NG
OK©GO TO 5.
NG©Replace EGR temperature sensor.
DTC P1401 EGR TEMPERATURE SENSOR
(IF SO EQUIPPED)QG16I18DE
Diagnostic Procedure
EC-303
Page 746 of 2267
5 CHECK EGR VOLUME CONTROL VALVE
Refer to ªComponent Inspectionº, EC-QG-251.
OK or NG
OK©GO TO 6.
NG©Replace EGR volume control valve.
6 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-QG-102.
©INSPECTION END
Component InspectionNCEC0348EGR TEMPERATURE SENSORNCEC0348S01Check resistance change and resistance value.
EGR temperature
ÉC (ÉF)Voltage
VResistance
MW
0 (32) 4.56 0.62 - 1.05
50 (122) 2.25 0.065 - 0.094
100 (212) 0.59 0.011 - 0.015
If NG, replace EGR temperature sensor.
SEF643Q
SEF068X
DTC P1401 EGR TEMPERATURE SENSOR
(IF SO EQUIPPED)QG16I18DE
Diagnostic Procedure (Cont'd)
EC-304
Page 747 of 2267

DescriptionNCEC0349SYSTEM DESCRIPTIONNCEC0349S01
Sensor Input Signal to ECMECM
functionActuator
Crankshaft position sensor (POS) 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 close under the following conditions.
IExtremely light load engine operation
IMass air flow sensor malfunction
IEngine idling
ILow engine coolant temperature
IExcessively high engine coolant temperature
IHigh-speed engine operation
IWide open throttle
ILow battery voltage
IEngine starting
COMPONENT DESCRIPTIONNCEC0349S02EGR Volume Control ValveNCEC0349S0201The 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 P1402 EGR FUNCTION (OPEN) (IF SO EQUIPPED)QG16I18DE
Description
EC-305
Page 748 of 2267

CONSULT-II Reference Value in Data Monitor
Mode
NCEC0539Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
EGR TEMP SENIEngine: After warming up Less than 4.5V
EGR VOL CON/VIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 0 step
Revving engine up to 3,000 rpm
quickly10 - 55 step
ECM Terminals and Reference ValueNCEC0540Specification 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)
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 rpm.0 - 14V
58 B Sensor's ground[Engine is running.]
IWarm-up condition
IIdle speed0V
72 PU EGR temperature sensor[Engine is running.]
IWarm-up condition
IIdle speedLess than 4.5V
[Engine is running.]
IWarm-up condition
IEGR system is operating.0 - 1.0V
On Board Diagnosis LogicNCEC0350If EGR temperature sensor detects EGR flow under the condition
that does not call for EGR, a high-flow malfunction is diagnosed.
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P1402
1402IEGR flow is detected under conditions that do not call for
EGR.IHarness or connectors
(The valve circuit is open or shorted.)
IEGR volume control valve leaking or stuck open
IEGR temperature sensor
SEF073P
DTC P1402 EGR FUNCTION (OPEN) (IF SO EQUIPPED)QG16I18DE
CONSULT-II Reference Value in Data Monitor Mode
EC-306
Page 749 of 2267

DTC Confirmation ProcedureNCEC0351NOTE:
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:
IAlways perform at a temperature above þ10ÉC (14ÉF).
IEngine coolant temperature and EGR temperature must
be verified in ªDATA MONITORº mode with CONSULT-II
before starting DTC WORK SUPPORT test. If it is out of
range below, the test cannot be conducted.
COOLAN TEMP/S: þ10 to 40ÉC (14 to 104ÉF)*
EGR TEMP SEN: Less than 4.8V
If the values are out of the ranges indicated above, park
the vehicle in a cool place and allow the engine tempera-
ture to stabilize. Do not attempt to reduce the engine cool-
ant or EGR temperature with a fan or means other than
ambient air. Doing so may produce an inaccurate diagnos-
tic result.
*: Although CONSULT-II screen displays ªþ10 to 40ÉC (14 to
104ÉF)º as a range of engine coolant temperature, ignore it.
PEF347U
SEF127X
DTC P1402 EGR FUNCTION (OPEN) (IF SO EQUIPPED)QG16I18DE
DTC Confirmation Procedure
EC-307
Page 750 of 2267

With CONSULT-II
1) Turn ignition switch ªOFFº and wait at least 9 seconds, then
turn ignition switch ªONº.
2) Select ªEGR SYSTEM P1402º of ªEGR SYSTEMº in ªDTC
WORK SUPPORTº mode with CONSULT-II.
3) Touch ªSTARTº. Follow instructions of CONSULT-II.
4) Start engine and let it idle until ªTESTINGº on CONSULT-II
screen is turned to ªCOMPLETEDº. (It will take 45 seconds or
more.)
If ªTESTINGº is not displayed after 5 minutes, turn ignition
ªOFFº and cool the engine coolant temperature to the
range of þ10 to 40ÉC (14 to 104ÉF). Retry from step 1.
5) Make sure that ªOKº is displayed after touching ªSELF-DIAG
RESULTSº. If ªNGº is displayed, refer to ªDiagnostic
Procedureº, EC-QG-310.
With GST
1) Turn ignition switch ªONº and select ªMODE 1º with GST.
2) Check that engine coolant temperature is within the range of
þ10 to 40ÉC (14 to 104ÉF).
3) Check that voltage between ECM terminal 72 (EGR tempera-
ture sensor signal) and ground is less than 4.8V.
4) Start engine and let it idle for at least 45 seconds.
5) Stop engine.
6) Perform from step 1 to 4.
7) Select ªMODE 3º with GST.
8) If DTC is detected, go to ªDiagnostic Procedureº, EC-QG-310.
NEF115A
NEF116A
PEF897U
DTC P1402 EGR FUNCTION (OPEN) (IF SO EQUIPPED)QG16I18DE
DTC Confirmation Procedure (Cont'd)
EC-308
Page 751 of 2267
Wiring DiagramNCEC0352
YEC072A
DTC P1402 EGR FUNCTION (OPEN) (IF SO EQUIPPED)QG16I18DE
Wiring Diagram
EC-309
Page 752 of 2267

Diagnostic ProcedureNCEC0353
1 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.
SEF556WVoltage: Battery voltage
OK or NG
OK©GO TO 2.
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.
2 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 3.
NG©Repair open circuit, short to ground or short to power in harness connectors.
3 CHECK EGR TEMPERATURE SENSOR
Refer to ªComponent Inspectionº, EC-QG-304.
OK or NG
OK©GO TO 4.
NG©Replace EGR temperature sensor.
4 CHECK EGR VOLUME CONTROL VALVE
Refer to ªComponent Inspectionº, EC-QG-251.
OK or NG
OK©GO TO 5.
NG©Replace EGR volume control valve.
DTC P1402 EGR FUNCTION (OPEN) (IF SO EQUIPPED)QG16I18DE
Diagnostic Procedure
EC-310