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NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [L8, LF, L3]

id0103a1802300

17 | COOLING SYSTEM CONCERNS -OVERHEATING
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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
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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. Turn the ignition switch to the ON position (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, L3].)
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 blower fan to any speed. 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 in wiring harness between 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 blower fan any speed. Measure voltage at PCM terminal 1AP. (See PCM INSPECTION [L8, LF, L3].) Is voltage normal? | Yes | Go to the next step.
No | Inspect the following: • Refrigerant pressure switch operation • The A/C switch is stuck open. • Open or short circuit between refrigerant pressure switch and PCM terminal 1AU • Open circuit of blower motor fan switch and resistor (if blower motor does not operate) • The evaporator temperature sensor and A/C amplifier
5 | Inspect 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 part.
6 | Is the drive belt normal? | Yes | Go to the next step.
No | Replace the drive belt.
7 | Is there leakage around the heater unit in passenger compartment? | Yes | Inspect and service heater for leakage.
No | Go to the next step.
8 | Is there 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 thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [L8, LF, L3, L3 Turbo].) (See THERMOSTAT INSPECTION [L8, LF, L3, L3 Turbo].) Is thermostat normal? | Yes | The engine coolant temperature and thermostat are normal, inspect engine block for leakage or blockage.
No | Access ECT PID. Inspect for both ECT PID and temperature gauge readings. • If temperature gauge on instrument cluster indicates normal range but ECT PID is not same as temperature gauge reading, inspect ECT sensor. • If temperature gauge on instrument cluster indicates overheating but ECT PID is normal, inspect temperature gauge and heat gauge unit.
10 | • Verify test results. - If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [L8, LF, L3].) - If malfunction remains, inspect related Service Information and perform repair or diagnosis. • If vehicle is repaired, troubleshooting completed. • If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [L8, LF, L3].)