NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [L8, LF, L5]

id010346802300

17

COOLING SYSTEM CONCERNS -OVERHEATING

DESCRIPTION

Engine runs at higher than normal temperature/overheats.

POSSIBLE CAUSE

•  Improper coolant level

•  Blown fuses

•  Coolant leakage

•  Excessive A/C system pressure

•  A/C system operation is improper

•  Improper water/anti‐freeze mixture

•  Fans reverse rotation

•  Poor radiator condition

•  Thermostat malfunction

•  Radiator hoses damage

•  Improper or damaged radiator cap

•  Cooling fan is inoperative.

•  Coolant overflow system malfunction

•  Improper tension of drive belt

•  Drive belt damage

17	COOLING SYSTEM CONCERNS -OVERHEATING
DESCRIPTION	Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE	• Improper coolant level • Blown fuses • Coolant leakage • Excessive A/C system pressure • A/C system operation is improper • Improper water/anti‐freeze mixture • Fans reverse rotation • Poor radiator condition • Thermostat malfunction • Radiator hoses damage • Improper or damaged radiator cap • Cooling fan is inoperative. • Coolant overflow system malfunction • Improper tension of drive belt • Drive belt damage

Diagnostic procedure

STEP	INSPECTION	RESULTS	ACTION
1	Inspect the following: • Engine coolant level • Coolant leakage • Water and anti‐freeze mixture • Radiator condition • Collapsed or restricted radiator hoses • Radiator pressure cap • Overflow system • Fan rotational direction • Fuses Are all the items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	Connect the M-MDS to the DLC-2. Switch the ignition to ON (Engine off). Retrieve any DTCs. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [L8, LF, L5].)
2		No	No DTC is displayed: Go to the next step.
3	Start the engine and idle it. Turn the A/C switch on and set the blower fan to any speed. Does the A/C compressor engage?	Yes	Go to Step 5.
3		No	Inspect for the following and repair or replace if necessary: • Refrigerant charging amount • Open circuit in the wiring harness between the A/C relay and PCM terminal 1I • Seized A/C magnetic clutch • A/C magnetic clutch malfunction If all items are normal, go to the next step.
4	Start the engine and idle it. Turn the A/C switch on and set the blower fan to any speed. Measure the voltage at PCM terminal 1AW. (See PCM INSPECTION [L8, LF, L5].) Is the voltage normal?	Yes	Go to the next step.
4		No	Inspect the following: • Refrigerant pressure switch operation • The A/C switch is stuck open. • Open or short circuit between the refrigerant pressure switch and PCM terminal 1AW • Open circuit in the blower motor fan switch and the resistor (if blower motor does not operate) • The evaporator temperature sensor and A/C amplifier
5	Inspect the cooling fan control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF, L5].) Does the cooling fan control system function properly?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part.
6	Is the drive belt normal? (See DRIVE BELT INSPECTION [L8, LF, L5].)	Yes	Go to the next step.
6		No	Replace the drive belt. (See DRIVE BELT REMOVAL/INSTALLATION [L8, LF, L5].)
7	Is there leakage around the heater unit in the passenger compartment?	Yes	Inspect and service heater for leakage.
7		No	Go to the next step.
8	Is there leakage at the coolant hoses and/or radiator?	Yes	Replace the malfunctioning part.
8	Is there leakage at the coolant hoses and/or radiator?	No	Go to the next step.
9	Cool down the engine. Remove thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [L8, LF, L5].) (See THERMOSTAT INSPECTION [L8, LF, L5].) Is the thermostat normal?	Yes	The engine coolant temperature and thermostat are normal, inspect engine block for leakage or blockage.
9		No	Access ECT PID. Inspect both the ECT PID and temperature gauge readings. • If the temperature gauge on instrument cluster indicates a normal range but the ECT PID is not the same as the temperature gauge reading, inspect the ECT sensor. • If the temperature gauge on the instrument cluster indicates overheating but the ECT PID is normal, inspect the temperature gauge and the heat gauge unit.
10	• Verify the test results. ― If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [L8, LF, L5].) ― If the malfunction remains, inspect the related Service Information and perform 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 [L8, LF, L5].)