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
ECM Terminals and Reference Value=NJEC0487Specification 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)
13 LG/R Cooling fan relay[Engine is running]
+Cooling fan is not operatingBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
+Cooling fan is operating0 - 0.6V
23 L/W Air conditioner switch[Engine is running]
+Both air conditioner switch and blower switch are
ªONº (Compressor operates)Approximately 0V
[Engine is running]
+Air conditioner switch is ªOFFºBATTERY VOLTAGE
(11 - 14V)
On Board Diagnosis LogicNJEC0572If the cooling fan or another component in the cooling system malfunctions, engine coolant temperature will
rise.
When the engine coolant temperature reaches an abnormally high temperature condition, a malfunction is
indicated.
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P1217
1217+The engine coolant temperature is extraordinary high,
even when the load is not heavy.+Harness or connectors
(The cooling fan circuit is open or shorted)
+Cooling fan
+Thermostat
+Improper ignition timing
+Engine coolant temperature sensor
+Blocked radiator
+Blocked front end (Improper fitting of nose mask)
+Crushed vehicle frontal area (Vehicle frontal is
collided but not repaired)
+Blocked air passage by improper installation of
front fog lamp or fog lamps.
+Improper mixture ratio of coolant
+Damaged bumper
For more information, refer to ªMAIN 12 CAUSES
OF OVERHEATINGº, EC-345.
CAUTION:
When a malfunction is indicated, be sure to replace the coolant following the procedure in the LC-17,
ªChanging Engine Coolantº. Also, replace the engine oil.
1) Fill radiator with coolant up to specified level with a filling speed of 2 liters per minute. Be sure to use
coolant with the proper mixture ratio. Refer to MA-22, ªAnti-freeze Coolant Mixture Ratioº, ªRECOM-
MENDED FLUIDS AND LUBRICANTSº.
2) After refilling coolant, run engine to ensure that no water-flow noise is emitted.
DTC P1217 OVERHEAT (COOLING SYSTEM)QG
ECM Terminals and Reference Value
EC-335
SEF621WA
SEF646X
SEC163BA
Overall Function CheckNJEC0489Use this procedure to check the overall function of the cooling fan.
During this check, a DTC might not be confirmed.
WARNING:
Never remove the radiator cap when the engine is hot. Serious
burns could be caused by high pressure fluid escaping from
the radiator.
Wrap a thick cloth around cap. Carefully remove the cap by
turning it a quarter turn to allow built-up pressure to escape.
Then turn the cap all the way off.
With CONSULT-II
1) Check the coolant level and mixture ratio (using coolant tester)
in the reservoir tank and radiator.
Allow engine to cool before checking coolant level and
mixture ratio.
+If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-339.
+If the coolant mixture ratio is out of the range of 45 to 55%,
replace the coolant in the following procedure LC-17, ªChang-
ing Engine Coolantº.
2) Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-339.
3) Turn ignition switch ªONº.
4) Perform ªCOOLING FANº in ªACTIVE TESTº mode with CON-
SULT-II.
5) If the results are NG, go to ªDiagnostic Procedureº, EC-339.
Without CONSULT-II
1) Check the coolant level and mixture ratio (using coolant tester)
in the reservoir tank and radiator.
Allow engine to cool before checking coolant level and
mixture ratio.
+If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-339.
+If the coolant mixture ratio is out of the range of 45 to 55%,
replace the coolant in the following procedure LC-17, ªChang-
ing Engine Coolantº.
2) Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-339.
3) Start engine.
Be careful not to overheat engine.
4) Set temperature control lever to full cold position.
5) Turn air conditioner switch ªONº.
6) Turn blower fan switch ªONº.
7) Run engine at idle for a few minutes with air conditioner oper-
ating.
Be careful not to overheat engine.
8) Make sure that cooling fan operates. Refer to ªOPERATIONº
table for cooling fan, EC-334.
If NG, go to ªDiagnostic Procedureº, EC-339.
DTC P1217 OVERHEAT (COOLING SYSTEM)QG
On Board Diagnosis Logic (Cont'd)
EC-336
Main 12 Causes of Overheating=NJEC0492
Engine Step Inspection item Equipment Standard Reference page
OFF 1+Blocked radiator
+Blocked condenser
+Blocked radiator grille
+Blocked bumper+Visual No blocking Ð
2+Coolant mixture+Coolant tester 50 - 50% coolant mixture See MA-20, ªRECOM-
MENDED FLUIDS AND
LUBRICANTSº.
3+Coolant level+Visual Coolant up to MAX level
in reservoir tank and
radiator filler neckSee LC-17, ªChanging
Engine Coolantº.
4+Radiator cap+Pressure tester 59 - 98 kPa
(0.59 - 0.98 bar, 0.6 - 1.0
kg/cm
2,9-14psi) (Limit)See LC-10, ªSystem
Checkº.
ON*
25+Coolant leaks+Visual No leaks See LC-10, ªSystem
Checkº.
ON*
26+Thermostat+Touch the upper and
lower radiator hosesBoth hoses should be
hotSee LC-15, ªThermostatº
and LC-16, ªRadiatorº.
ON*
17+Cooling fan+CONSULT-II Operating See ªTROUBLE DIAG-
NOSIS FOR OVER-
HEATº (EC-334).
OFF 8+Combustion gas leak+Color checker chemi-
cal tester 4 Gas ana-
lyzerNegative Ð
ON*
39+Coolant temperature
gauge+Visual Gauge less than 3/4
when drivingÐ
+Coolant overflow to
reservoir tank+Visual No overflow during driv-
ing and idlingSee LC-17, ªChanging
Engine Coolantº.
OFF*
410+Coolant return from
reservoir tank to radia-
tor+Visual Should be initial level in
reservoir tankSee LC-18, ªRefilling
Engine Coolantº.
OFF 11+Cylinder head+Straight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)See EM-36, ªInspectionº,
ªCYLINDER HEADº.
12+Cylinder block and
pistons+Visual No scuffing on cylinder
walls or pistonSee EM-54, ªInspectionº,
ªCYLINDER BLOCKº.
*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 LC-23, ª OVERHEATING CAUSE ANALYSISº.
SEF745U
Component InspectionNJEC0493COOLING FAN RELAYNJEC0493S01Check continuity between terminals 3 and 5, 6 and 7.
Conditions Continuity
12V direct current supply between terminals 1 and
2Ye s
No current supply No
If NG, replace relay.
DTC P1217 OVERHEAT (COOLING SYSTEM)QG
Main 12 Causes of Overheating
EC-345
DescriptionNJEC1758SYSTEM DESCRIPTIONNJEC1758S01
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 DESCRIPTIONNJEC1758S02IACV-AAC ValveNJEC1758S0201The 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.
IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
QG
Description
EC-418
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA(DC Voltage)
221 LG/B Cooling fan relay (High)[Engine is running]
+Cooling fans are not operating
+Cooling fans are operating at low speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
+Cooling fans are operating at high speedApproximately 0.1V
On Board Diagnosis LogicNJEC0663This diagnosis continuously monitors the engine coolant temperature.
If the cooling fan or another component in the cooling system malfunctions, engine coolant temperature will
rise.
When the engine coolant temperature reaches an abnormally high temperature condition, a malfunction is
indicated.
DTC Malfunction is detected when ... Check Items (Possible Cause)
P1217
0208+Cooling fan does not operate properly (Overheat).
+Cooling fan system does not operate properly
(Overheat).
+Engine coolant was not added to the system using
the proper filling method.+Harness or connectors
(The cooling fan circuit is open or shorted.)
+Cooling fan
+Radiator hose
+Radiator
+Radiator cap
+Water pump
+Thermostat
+Engine coolant temperature sensor
For more information, refer to ªMAIN 12 CAUSES OF
OVERHEATINGº, EC-633.
CAUTION:
When a malfunction is indicated, be sure to replace the coolant following the procedure in the LC-43,
ªChanging Engine Coolantº. Also, replace the engine oil.
1) Fill radiator with coolant up to specified level with a filling speed of 2 liters per minute. Be sure
to use coolant with the proper mixture ratio. Refer to MA-22, ªEngine Coolant Mixture Ratioº.
2) After refilling coolant, run engine to ensure that no water-flow noise is emitted.
DTC P1217 OVER HEATYD
ECM Terminals and Reference Value (Cont'd)
EC-619
AEC640
SEF111X
SEC163BA
MEC475B
Overall Function CheckNJEC0664Use this procedure to check the overall function of the cooling fan.
During this check, a DTC might not be confirmed.
WARNING:
Never remove the radiator cap when the engine is hot. Serious
burns could be caused by high pressure fluid escaping from
the radiator.
Wrap a thick cloth around the cap. Carefully remove the cap
by turning it a quarter turn to allow built-up pressure to
escape. Then turn the cap all the way off.
WITH CONSULT-IINJEC0664S011) Check the coolant level in the reservoir tank and radiator.
Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-622.
2) Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-622.
3) Turn ignition switch ªONº.
4) Perform ªCOOLING FANº in ªACTIVE TESTº mode with CON-
SULT-II and make sure that cooling fans operate when touch-
ing ªHIGHº or ªLOWº.
If NG, go to ªDiagnostic Procedureº, EC-622.
WITHOUT CONSULT-IINJEC0664S021) Check the coolant level in the reservoir tank and radiator.
Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-622.
2) Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to ªDiagnos-
tic Procedureº, EC-622.
3) Start engine.
Be careful not to overheat engine.
4) Set temperature control lever to full cold position.
5) Turn air conditioner switch ªONº.
6) Turn blower fan switch ªONº.
7) Run engine at idle for a few minutes with air conditioner oper-
ating.
Be careful not to overheat engine.
8) Make sure that cooling fans operate at low speed.
9) Turn ignition switch ªOFFº.
10) Turn air conditioner switch and blower fan switch ªOFFº.
11) Disconnect engine coolant temperature sensor harness con-
nector.
12) Connect 150Wresistor to engine coolant temperature sensor
harness connector.
13) Start engine and make sure that cooling fans operate at higher
speed than low speed.
Be careful not to overheat engine.
14) If NG, go to ªDiagnostic Procedureº, EC-622.
DTC P1217 OVER HEATYD
On Board Diagnosis Logic (Cont'd)
EC-620
9 CHECK INTERMITTENT INCIDENT
1. Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-559.
©INSPECTION END
Main 12 Causes of OverheatingNJEC0667
Engine Step Inspection item Equipment Condition Reference page
OFF 1+Blocked radiator
+Blocked radiator grille
+Blocked bumper+Visual No blocking Ð
2+Coolant mixture+Coolant tester 50 - 50% coolant mixture See MA-20, ªRECOM-
MENDED FLUIDS AND
LUBRICANTSº.
3+Coolant level+Visual Coolant up to MAX level
in reservoir tank and
radiator filler neckSee LC-17, ªChanging
Engine Coolantº.
4+Radiator cap+Pressure tester 78 - 98 kPa
(0.78 - 0.98 bar, 0.8 - 1.0
kg/cm
2, 11 - 14 psi)See LC-37, ªSystem
Checkº.
ON*
25+Coolant leaks+Visual No leaks See LC-37, ªSystem
Checkº.
ON*
26+Thermostat+Touch the upper and
lower radiator hosesBoth hoses should be
hotSee LC-40, ªThermostatº
and ªRadiatorº.
ON*
17+Cooling fan+CONSULT-II Operating See Trouble Diagnosis
for DTC P1217, EC-618.
OFF 8+Combustion gas leak+Color checker chemi-
cal tester 4 Gas ana-
lyzerNegative Ð
ON*
39+Coolant temperature
gauge+Visual Gauge less than 3/4
when drivingÐ
+Coolant overflow to
reservoir tank+Visual No overflow during driv-
ing and idlingSee LC-43, ªChanging
Engine Coolantº.
OFF*
410+Coolant return from
reservoir tank to radia-
tor+Visual Should be initial level in
reservoir tankSee LC-43, ªREFILLING
ENGINE COOLANTº.
OFF 11+Cylinder head+Straight gauge feeler
gauge0.1mm (0.004 in) Maxi-
mum distortion (warping)See EM-121, ªInspec-
tionº.
12+Cylinder block and
pistons+Visual No scuffing on cylinder
walls or pistonSee EM-143, ªInspec-
tionº.
*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 LC-46, ªOVERHEATING CAUSE ANALYSISº.
DTC P1217 OVER HEATYD
Diagnostic Procedure (Cont'd)
EC-633