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	Perform the KOEO and 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	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 low engine coolant temperature indicator light on instrument cluster condition. • If the low engine coolant temperature indicator light on the instrument cluster indicates turned 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 [ZJ, ZY].) ― Replace the ECT sensor, if necessary. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [ZJ, ZY].) • If the low engine coolant temperature indicator light indication on the instrument cluster illuminates but the ECT PID is normal: ― Inspect the instrument cluster. (See INSTRUMENT CLUSTER INSPECTION.) ― Replace the instrument cluster, if necessary. (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)
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 test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [ZJ, ZY].) • If the 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 [ZJ, ZY].)