NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [SKYACTIV-G 2.5T]

id0103q4802300

17

COOLING SYSTEM CONCERNS-OVERHEATING
DESCRIPTION
•  Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE
•  Engine heat generation amount is excessive
?  Engine speed is high and remains high for continuous long periods
•  PCM DTC is stored
•  Improper operation of A/C system
•  Insufficient air blow volume
?  Cooling fan inoperative
?  Fan rotation speed decreases (such as generator malfunction) due to battery voltage decrease
•  Cooling system cap malfunction
•  Cooling fan motor assembly malfunction
•  Cooling fan motor connector malfunction
•  Improper indication of low engine coolant temperature indicator light and/or high engine coolant temperature warning light
?  ECT sensor malfunction
?  Instrument cluster malfunction
•  Blown fuse
•  Engine coolant system malfunction
?  Engine coolant performance deterioration
?  Coolant leakage (engine internal, turbocharger, external)
?  Improper water/anti-freeze mixture
?  Thermostat malfunction (not fully open)
?  Radiator malfunction (clogging)
•  Improper engine coolant level
?  Leakage around heater unit in passenger compartment
•  Drive belt damage

Diagnostic Procedure

STEP

INSPECTION

RESULTS

ACTION
1
INSPECT VEHICLE CONDITION FOR EFFECT ON MALFUNCTION
•  Verify how the customer drives the vehicle by asking the customer the following:
?  Engine speed is high and remains high for continuous long periods like when climbing a long, steep grade.
•  Is the engine generating excessive heat when driven?
Yes
Explain to the customer that the vehicle is normal and give them advice how to use vehicle and provide a specific example of the conditions in which the engine overheats.
No
Go to the next step.
2
VERIFY PCM DTC
•  Retrieve PCM DTCs using the M-MDS.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [PCM (SKYACTIV-G 2.5T)].)
No
Go to the next step.
3
DETERMINE IF MALFUNCTION CAUSE IS A/C SYSTEM OR OTHER
•  Start the engine and run it at idle speed.
•  Turn the A/C switch off.
•  Does the A/C compressor disengaged?
Yes
Go to the next step.
No
Perform the symptom troubleshooting “NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”.
(See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [SKYACTIV-G 2.5T].)
4
INSPECT ECT SENSOR SIGNAL
•  Access the ECT PID using the M-MDS.
•  Compare the ECT PID and low engine coolant temperature indicator light and high engine coolant temperature warning light operation.
•  Is the ECT PID value same as indicator/warning light readings?
Yes
Go to the next step.
No
Inspect the ECT sensor.
(See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [SKYACTIV-G 2.5T].)
•  If there is any malfunction:
?  Replace the ECT sensor.
•  If there is no malfunction:
?  Perform the instrument cluster symptom troubleshooting “LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT/HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLASHES CONTINUOUSLY”.
5
INSPECT COOLING FAN CONTROL SYSTEM OPERATION
•  Perform the Cooling Fan Control System Inspection.
•  Does the cooling fan control system operate properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
6
INSPECT COOLING SYSTEM CAP
•  Inspect the cooling system cap.
•  Is there any malfunction?
Yes
Replace the cooling system cap.
No
Go to the next step.
7
INSPECT RELATED PART CONDITION
•  Inspect the following:
?  Engine coolant performance
?  Coolant leakage (engine internal, external)
?  Water and anti-freeze mixture
?  Thermostat (not fully open)
?  Radiator (clogging)
?  Fuses
•  Is there any malfunction?
Yes
Service if necessary.
•  Repeat this step.
No
Go to the next step.
8
VERIFY IF MALFUNCTION CAUSED BY LACK OF ENGINE COOLANT
•  Inspect the engine coolant level.
•  Is there any malfunction?
Yes
Add engine coolant and verify that there is no engine coolant leakage.
(See ENGINE COOLANT REPLACEMENT [SKYACTIV-G 2.5T].)
(See ENGINE COOLANT LEAKAGE INSPECTION [SKYACTIV-G 2.5T].)
•  If there is any malfunction:
?  Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
9
DETERMINE IF MALFUNCTION CAUSE IS THERMOSTAT OR OTHER
•  Verify the radiator hose tension.
Warning
•  To prevent burns, use a cloth with your hand to verify the tension of the radiator hose.
•  After the engine warms up, does the engine coolant circulate to the radiator hose?
Yes
Go to Step 11.
No
Go to the next step.
10
INSPECT THERMOSTAT
•  Inspect the thermostat.
•  Is the thermostat normal?
Yes
Inspect the water pump.
•  If there is any malfunction:
?  Repair or replace the malfunctioning part according to the inspection results.
No
Replace the thermostat.
(See THERMOSTAT REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
11
INSPECT DRIVE BELT
•  Inspect the drive belt.
•  Is the indicator mark on the drive belt auto tensioner within the normal range?
Yes
Go to the next step.
No
Replace the drive belt.
(See DRIVE BELT REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
12
INSPECT RADIATOR FOR CLOGGING
•  Inspect for clogging in the radiator.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Replace the engine coolant.
(See ENGINE COOLANT REPLACEMENT [SKYACTIV-G 2.5T].)
13
Verify the test results.
•  If normal, return to the diagnostic index to service any additional symptoms.
•  If a malfunction remains, inspect the related Service Information and perform the repair or diagnosis.
?  If the vehicle is repaired, troubleshooting is completed.
?  If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM.