NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [ZJ, ZY]

id0103b0802300

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/KOER self test. (See KOEO/KOER SELF TEST [ZJ, ZY].) Are any continuous memory DTCs present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [ZJ, ZY].)
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 1AN • 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	Connect the M-MDS to the DLC-2. Perform the PID/DATA Monitor and Record Procedure and access the AC_REQ PID. (See ON-BOARD DIAGNOSTIC TEST [ZJ, ZY].) 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: • A/C switch is stuck open • Evaporator temperature sensor and A/C amplifier • Open or short circuit between refrigerant pressure switch and PCM terminal 1AO • Open circuit of blower motor fan switch and resistor (if blower motor does not operate) • Refrigerant pressure switch operation 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 [ZJ, ZY].) 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 [ZJ, ZY].) Is there any malfunction?	Yes	Replace the drive belt. (See DRIVE BELT REMOVAL/INSTALLATION [ZJ, ZY].)
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 [ZJ, ZY].) Inspect the thermostat. (See THERMOSTAT INSPECTION [ZJ, ZY].) Is there any malfunction?	Yes	Perform the PID/DATA Monitor and Record Procedure and access the ECT PID. (See ON-BOARD DIAGNOSTIC TEST [ZJ, ZY].) Inspect for both the ECT PID and the temperature gauge readings. If the temperature gauge on the instrument cluster indicates normal range but ECT PID is not same as the temperature gauge reading: • Inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [ZJ, ZY].) • Replace the ECT sensor, if necessary. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [ZJ, ZY].) If the temperature gauge on the instrument cluster indicates overheating but ECT PID is normal: • Inspect the temperature gauge and the heat gauge unit. • Repair or replace the malfunctioning part according to the inspection results.
9		No	Engine coolant temperature 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 test results. • If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [ZJ, ZY].) • 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 [ZJ, ZY].)