NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR 1.6]

id0103f9802300

17

COOLING SYSTEM CONCERNS—OVERHEATING

DESCRIPTION

•  The engine runs at higher than normal temperature/overheats.

POSSIBLE CAUSE

•  Radiator hose damage

•  Coolant leakage

•  Improper coolant level

•  Fans reverse rotation

•  Fuse malfunction

•  Coolant overflow system malfunction

•  Poor radiator condition

•  Improper or damaged radiator cap

•  Improper water/anti-freeze mixture

•  Continuous memory DTC is stored

•  A/C system operation is improper

•  Excessive A/C system pressure

•  Improper operation of cooling fan control system

•  Drive belt malfunction

•  Leakage around heater unit in passenger compartment

•  Leakage at coolant hoses and/or radiator

•  Thermostat malfunction

•  ECT sensor malfunction

•  PCM malfunction

17	COOLING SYSTEM CONCERNS—OVERHEATING
DESCRIPTION	• The engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE	• Radiator hose damage • Coolant leakage • Improper coolant level • Fans reverse rotation • Fuse malfunction • Coolant overflow system malfunction • Poor radiator condition • Improper or damaged radiator cap • Improper water/anti-freeze mixture • Continuous memory DTC is stored • A/C system operation is improper • Excessive A/C system pressure • Improper operation of cooling fan control system • Drive belt malfunction • Leakage around heater unit in passenger compartment • Leakage at coolant hoses and/or radiator • Thermostat malfunction • ECT sensor malfunction • PCM malfunction

Diagnostic Procedure

STEP	INSPECTION	ACTION
1	Inspect the following: • Collapsed or restricted radiator hoses • Coolant leakage • Engine coolant level • Fan rotational direction • Fuses • Overflow system • Radiator condition • Radiator pressure cap • Water and anti-freeze mixture Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
1		No	Go to the next step.
2	Connect the M-MDS to the DLC-2. Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST [MZR 1.6].) Are any continuous memory DTCs present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [MZR 1.6].)
2		No	Go to the next step.
3	Start the engine and idle it. Turn the A/C switch on. Does the A/C compressor engage?	Yes	Go to Step 5.
3		No	Inspect the following: • A/C magnetic clutch malfunction • Open circuit in wiring harness between A/C relay and PCM terminal 1AT • Refrigerant charging amount • Seized A/C magnetic clutch If there is a malfunction: • Repair or replace the malfunctioning part according to the inspection results. If all items are normal: • Go to the next step.
4	Access the AC_REQ PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.6].) Start the engine and idle it. Turn the A/C switch on. Does the AC_REQ PID read ON?	Yes	Go to the next step.
4		No	Inspect the following: • Climate control unit malfunction ― A/C switch is stuck open ― Open circuit of blower motor fan switch and resistor (if blower motor does not operate) ― Evaporator temperature sensor and A/C amplifier Repair or replace the malfunctioning part according to the inspection results.
5	Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 1.6].) Does the cooling fan control system function properly?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part according to the inspection results.
6	Inspect the drive belt. (See DRIVE BELT INSPECTION [MZR 1.6].) Is there any malfunction?	Yes	Replace the drive belt. (See DRIVE BELT REMOVAL/INSTALLATION [MZR 1.6].)
6		No	Go to the next step.
7	Visually inspect the leakage around heater unit in passenger compartment. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
7		No	Go to the next step.
8	Visually inspect the leakage at coolant hoses and/or radiator. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
8		No	Go to the next step.
9	Cool down the engine. Remove the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 1.6].) Inspect the thermostat operation. (See THERMOSTAT INSPECTION [MZR 1.6].) Is there any malfunction?	Yes	Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.6].) Inspect for both the ECT PID and the low engine coolant temperature indicator light on instrument cluster condition. • If the low engine coolant temperature indicator light on the instrument cluster turns off but the ECT PID is not same as the low engine coolant temperature indicator light condition: ― Inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [MZR 1.6].) ― Replace the ECT sensor, if necessary. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [MZR 1.6].) • If the low engine coolant temperature indicator light on the instrument cluster indicates overheating but the ECT PID is normal: ― Inspect the instrument cluster. (See INSTRUMENT CLUSTER INSPECTION.) • Repair or replace the malfunctioning part according to the inspection results.
9		No	ECT sensor and thermostat are normal: • Inspect the engine block for leakage or blockage. • Repair or replace the malfunctioning part according to the inspection results.
10	Verify the test results. • If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 1.6].) • If malfunction remains, inspect related Service information perform repair or diagnosis. ― If vehicle repaired, troubleshooting completed. ― If vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 1.6].)