Page 737 of 2267

4 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M70, E125
I10A fuse
I40A fusible link
IHarness for open or short between cooling fan relay and fuse
IHarness for open or short between cooling fan relay and battery
©Repair open circuit or short to ground or short to power in harness or connectors.
5 CHECK GROUND CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect cooling fan motor-1 harness connector and cooling fan motor-2 harness connector.
SEF113X3. Check harness continuity between relay terminal 5 and motor-1 terminal 1, motor-1 terminal 2 and body ground. Refer to wiring dia-
gram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
5. Check harness continuity between relay terminal 5 and motor-2 terminal 1, motor-2 terminal 2 and body ground. Refer to wiring dia-
gram.
Continuity should exist.
6. 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 OUTPUT SIGNAL CIRCUIT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 13 and relay terminal 1. 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 8.
NG©GO TO 7.
7 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E42, F4
IHarness for open or short between cooling fan relay and ECM
©Repair open circuit or short to ground or short to power in harness or connectors.
DTC P1217 OVERHEAT (COOLING SYSTEM)QG16I18DE
Diagnostic Procedure (Cont'd)
EC-295
Page 738 of 2267
8 CHECK COOLING FAN RELAY
Refer to ªComponent Inspectionº, EC-QG-299.
OK or NG
OK©GO TO 9.
NG©Replace cooling fan relay.
9 CHECK COOLING FAN MOTORS-1 AND -2
Refer to ªComponent Inspectionº, EC-QG-299.
OK or NG
OK©GO TO 10.
NG©Replace cooling fan motors.
10 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-QG-102.
©INSPECTION END
11 CHECK COOLING SYSTEM FOR LEAK
Apply pressure to the cooling system with a tester, and check if the pressure drops.
Testing pressure: 157 kPa (1.57 bar, 1.6 kg/cm2, 23 psi)
CAUTION:
Higher than the specified pressure may cause radiator damage.
SLC754APressure should not drop.
OK or NG
OK©GO TO 12.
NG©Check the following for leak
IHose
IRadiator
IWater pump
Refer to LC section (ªWater Pumpº).
DTC P1217 OVERHEAT (COOLING SYSTEM)QG16I18DE
Diagnostic Procedure (Cont'd)
EC-296
Page 739 of 2267

12 CHECK RADIATOR CAP
Apply pressure to cap with a tester.
SLC755ARadiator cap relief pressure:
59 - 98 kPa (0.59 - 0.98 bar, 0.6 - 1.0 kg/cm2,9-14psi)
OK or NG
OK©GO TO 13.
NG©Replace radiator cap.
13 CHECK THERMOSTAT
1. Check valve seating condition at normal room temperatures.
It should seat tightly.
2. Check valve opening temperature and valve lift.
SLC343Valve opening temperature:
76.5ÉC (170ÉF) [standard]
Valve lift:
More than 8 mm/90ÉC (0.31 in/194ÉF)
3. Check if valve is closed at 5ÉC (9ÉF) below valve opening temperature.
For details, refer to LC section (ªThermostatº).
OK or NG
OK©GO TO 14.
NG©Replace thermostat
14 CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to ªComponent Inspectionº, EC-QG-124.
OK or NG
OK©GO TO 15.
NG©Replace engine coolant temperature sensor.
15 CHECK MAIN 12 CAUSES
If the cause cannot be isolated, go to ªMAIN 12 CAUSES OF OVERHEATINGº, EC-QG-298.
©INSPECTION END
DTC P1217 OVERHEAT (COOLING SYSTEM)QG16I18DE
Diagnostic Procedure (Cont'd)
EC-297
Page 740 of 2267

Main 12 Causes of OverheatingNCEC0492
Engine Step Inspection item Equipment Standard Reference page
OFF 1IBlocked radiator
IBlocked condenser
IBlocked radiator grille
IBlocked bumperIVisual No blocking Ð
2ICoolant mixtureICoolant tester 50 - 50% coolant mixture See ªRECOMMENDED
FLUIDS AND LUBRI-
CANTSº in MA section.
3ICoolant levelIVisual Coolant up to MAX level
in reservoir tank and
radiator filler neckSee ªChanging Engine
Coolantº, ªENGINE
MAINTENANCEº in MA
section.
4IRadiator capIPressure tester 59 - 98 kPa
(0.59 - 0.98 bar, 0.6 - 1.0
kg/cm
2,9-14psi) (Limit)See ªSystem Checkº,
ªENGINE COOLING
SYSTEMº in LC section.
ON*
25ICoolant leaksIVisual No leaks See ªSystem Checkº,
ªENGINE COOLING
SYSTEMº in LC section.
ON*
26IThermostatITouch the upper and
lower radiator hosesBoth hoses should be hot See ªThermostatº and
ªRadiatorº, ªENGINE
COOLING SYSTEMº in
LC section.
ON*
17ICooling fanICONSULT-II Operating See ªTROUBLE DIAG-
NOSIS FOR OVER-
HEATº (EC-QG-289).
OFF 8ICombustion gas leakIColor checker chemical
tester 4 Gas analyzerNegative Ð
ON*
39ICoolant temperature
gaugeIVisual Gauge less than 3/4
when drivingÐ
ICoolant overflow to
reservoir tankIVisual No overflow during driv-
ing and idlingSee ªChanging Engine
Coolantº, ªENGINE
MAINTENANCEº in MA
section.
OFF*
410ICoolant return from
reservoir tank to radia-
torIVisual Should be initial level in
reservoir tankSee ªENGINE MAINTE-
NANCEº in MA section.
OFF 11ICylinder headIStraight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)See ªInspectionº, ªCYLIN-
DER HEADº in EM sec-
tion.
12ICylinder block and pis-
tonsIVisual No scuffing on cylinder
walls or pistonSee ªInspectionº, ªCYLIN-
DER BLOCKº in EM sec-
tion.
*1: Turn the ignition switch ON.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
For more information, refer to ªOVERHEATING CAUSE ANALYSISº in LC section.
DTC P1217 OVERHEAT (COOLING SYSTEM)QG16I18DE
Main 12 Causes of Overheating
EC-298
Page 741 of 2267

Component InspectionNCEC0493COOLING FAN RELAYSNCEC0493S01Check continuity between terminals 3 and 5.
Conditions Continuity
12V direct current supply between terminals 1 and
2Ye s
No current supply No
If NG, replace relay.
COOLING FAN MOTORS-1 AND -2NCEC0493S021. Disconnect cooling fan motor harness connectors.
2. Supply cooling fan motor terminals with battery voltage and
check operation.
Terminals
(+) (þ)
Cooling fan motor 1 2
Cooling fan motor should operate.
If NG, replace cooling fan motor.
REFRIGERANT PRESSURE SENSORNCEC0493S03With the refrigerant pressure sensor installed on the vehicle, start
the engine and while idling, read the voltage at refrigerant pressure
sensor terminals 1 and 2. (Refer to wiring diagram.)
Air conditioner condition Voltage V
OFF More than approx. 0.3V
ON More than approx. 1.5V
ON to OFF Decreasing gradually
If results are NG, check for 5V between refrigerant sensor termi-
nal 3 and ground. If there is 5V, replace sensor.
SEF511P
SEF721Q
DTC P1217 OVERHEAT (COOLING SYSTEM)QG16I18DE
Component Inspection
EC-299
Page 742 of 2267

Component DescriptionNCEC0342The EGR temperature sensor detects temperature changes in the
EGR passageway. When the EGR volume control valve opens, hot
exhaust gases flow, and the temperature in the passageway
changes. The EGR temperature sensor is a thermistor that modi-
fies a voltage signal sent from the ECM. This modified signal then
returns to the ECM as an input signal. As the temperature
increases, EGR temperature sensor resistance decreases. This
sensor is not used to control the engine system.
It is used only for the on board diagnosis.
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
*: These data are reference values and are measured between ECM terminal 72
(EGR temperature sensor) and ground.
When EGR system is operating.
Voltage: 0 - 1.5V
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.
On Board Diagnosis LogicNCEC0343
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P1401
1401A) An excessively low voltage from the EGR tempera-
ture sensor is sent to ECM even when engine cool-
ant temperature is low.IHarness or connectors
(The EGR temperature sensor circuit is shorted.)
IEGR temperature sensor
IMalfunction of EGR function
B) An excessively high voltage from the EGR tempera-
ture sensor is sent to ECM even when engine cool-
ant temperature is high.IHarness or connectors
(The EGR temperature sensor circuit is open.)
IEGR temperature sensor
IMalfunction of EGR function
DTC Confirmation ProcedureNCEC0344Perform ªPROCEDURE FOR MALFUNCTION Aº first. If 1st trip
DTC cannot be confirmed, perform ªPROCEDURE FOR MAL-
FUNCTION Bº.
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.
SEF599K
SEF068X
DTC P1401 EGR TEMPERATURE SENSOR
(IF SO EQUIPPED)QG16I18DE
Component Description
EC-300
Page 743 of 2267

PROCEDURE FOR MALFUNCTION A=NCEC0344S01With CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Verify that engine coolant temperature is less than 50ÉC
(122ÉF).
If the engine coolant temperature is above the range, cool
the engine down.
4) Start engine and let it idle for at least 5 seconds.
5) If 1st trip DTC is detected, go to ªDiagnostic Procedureº, EC-
QG-303.
With GST
Follow the procedure ªWith CONSULT-IIº above.
PROCEDURE FOR MALFUNCTION BNCEC0344S02CAUTION:
Always drive vehicle at a safe speed.
TESTING CONDITION:
Always perform the test at a temperature above þ10ÉC (14ÉF).
With CONSULT-II
1) Start engine and warm it up to above 80ÉC (176ÉF).
2) Select ªEGR VOL CONT/Vº in ªACTIVE TESTº mode with
CONSULT.
3) Hold engine speed at 1,500 rpm.
4) Touch ªQuº and set the EGR volume control valve opening to
50 step and check EGR TEMP SEN.
EGR TEMP SEN should decrease to less than 1.0V.
If the check result is NG, go to ªDiagnostic Procedureº, EC-
QG-303.
If the check result is OK, go to the following step.
5) Turn ignition switch ªOFFº and wait at least 9 seconds.
6) Start engine and maintain the following conditions for at least
5 consecutive seconds.
ENG SPEED Above 2,400 rpm
VHCL SPEED SE Above 90 km/h (56 MPH) or more
B/FUEL SCHDL 4.0 - 4.8 msec
Selector lever 4th or 5th
7) If 1st trip DTC is detected, go to ªDiagnostic Procedureº, EC-
QG-303.
With GST
Follow the procedure ªWith CONSULT-IIº above.
NEF113A
NEF114A
DTC P1401 EGR TEMPERATURE SENSOR
(IF SO EQUIPPED)QG16I18DE
DTC Confirmation Procedure (Cont'd)
EC-301
Page 744 of 2267
Wiring DiagramNCEC0346
YEC074A
DTC P1401 EGR TEMPERATURE SENSOR
(IF SO EQUIPPED)QG16I18DE
Wiring Diagram
EC-302