#
NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [WITHOUT WU-TWC]

id0103008023c6

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 • Condenser fan is inoperative. • 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 items normal? | Yes | Go to the next step.
No | Service if necessary. Repeat Step 1.
2 | Connect the WDS or equivalent to the DLC-2. Retrieve any continuous memory, KOEO and KOER DTCs. (See KOEO/KOER SELF-TEST.) Are there any DTCs displayed? | Yes | DTC is displayed: Go to the appropriate DTC test.
No | No DTC is displayed: 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.
No | Inspect for the following and repair or replace if necessary: • Refrigerant charging amount • Open circuit between A/C relay and PCM terminal 1AL • Seized A/C magnetic clutch • A/C magnetic clutch malfunction If all items are normal, go to the next step.
4 | Connect the WDS or equivalent to the DLC-2. Access the ACSW PID. Start the engine and idle it. Turn the A/C switch on. Does the ACSW PID read "on"? | Yes | Go to the next step.
No | Inspect the following: • Refrigerant pressure switch operation • A/C switch is stuck open. • Open or short circuit between the refrigerant pressure switch and PCM terminal 1Q • Open circuit of blower motor fan switch and the resistor (if blower motor does not operate) • Evaporator temperature sensor and the A/C amplifier
5 | Inspect the cooling fan control system operation. (See Cooling Fan Control System Inspection.) Does the cooling fan control system function properly? | Yes | Go to the next step.
No | Repair or replace the malfunctioning parts.
6 | Is the drive belt normal? | Yes | Go to the next step.
No | Replace the drive belt.
7 | Is there any leakage around the heater unit in passenger compartment? | Yes | Inspect the service heater for leakage.
No | Go to the next step.
8 | Is there any leakage at the coolant hoses and/or radiator? | Yes | Replace the malfunctioning part.
No | Go to the next step.
9 | Cool down the engine. Remove the thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [ZJ, ZY].) (See THERMOSTAT INSPECTION [ZJ, ZY].) Is the thermostat normal? | Yes | Engine coolant temperature and the thermostat are normal, inspect the engine block for leakage or blockage.
No | Access the ECT PID. Inspect for both the ECT PID and temperature gauge readings. • If the temperature gauge on the instrument cluster indicates 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 heat gauge units.
10 | Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. • If the malfunction remains, replace or reprogram the PCM.