NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR 2.0 DISI i-stop]


id0103d3802300

17

COOLING SYSTEM CONCERNS-OVERHEATING

DESCRIPTION
•  Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE
•  Improper coolant level
•  Coolant leakage (engine internal, external)
•  Improper water/anti-freeze mixture
•  Poor radiator condition
•  Radiator hose damage
•  Improper or damaged radiator cap
•  Coolant overflow system malfunction
•  Fans reverse rotation
•  Blown fuse
•  PCM DTC is stored.
•  Improper operation of A/C system
•  Cooling fan inoperative
•  Drive belt damage
•  Improper drive belt tension
•  Leakage around heater unit in passenger compartment
•  Leakage at coolant hoses and/or radiator
•  Thermostat malfunction
•  Improper indication of low engine coolant temperature indicator light and/or high engine coolant temperature warning light
―  ECT sensor malfunction
―  Instrument cluster malfunction
•  Excessive A/C system pressure

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1
Inspect for the following:
•  Engine coolant level
•  Coolant leakage (around heater unit in passenger compartment, coolant hoses and/or radiator.)
•  Water and anti-freeze mixture
•  Radiator condition
•  Collapsed or restricted radiator hoses
•  Radiator pressure cap
•  Coolant overflow system
•  Fan rotational direction
•  Fuses
Is there any malfunction?
Yes
Service if necessary.
•  Repeat this step.
No
Go to the next step.
2
Connect the M-MDS to the DLC-2.
Switch the ignition to ON (engine off).
Retrieve any DTCs using the M-MDS.
Are any DTCs present?
Yes
Go to the applicable DTC inspection.
No
Go to the next step.
3
Perform the KOEO/KOER self test.
Are any DTCs present?
Yes
Go to the applicable DTC inspection.
No
Go to the next step.
4
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”.
5
Perform the Cooling Fan Control System Inspection.
Does the cooling fan system operate properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
6
Inspect the drive belt.
Is there any malfunction?
Yes
Replace the drive belt.
No
Go to the next step.
7
Inspect for leakage around heater unit in passenger compartment.
Is there any leakage?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
8
Inspect for leakage at coolant hoses and/or radiator.
Is there any leakage?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
9
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.
•  If there is any malfunction:
•  If there is no malfunction:
―  Perform the instrument cluster symptom troubleshooting “NO. 10 LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT/HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLASHES CONTINUOUSLY”.
10
Cool down the engine.
Remove the thermostat.
Inspect the thermostat operation.
Is there any malfunction?
Yes
Replace the thermostat.
No
Reinstall the thermostat.
The engine coolant temperature and thermostat are normal.
•  Inspect the engine block for leakage or blockage.
•  Repair or replace the malfunctioning part according to the inspection results.
11
Verify the test results.
•  If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 2.0 DISI i-stop].)
•  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. (See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].)