NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [ZJ, Z6]

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NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [ZJ, Z6]

B3E010318881W50

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 hose 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 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 using WDS or equivalent. Are there any DTCs displayed? | Yes | DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [ZJ, Z6].)
No | No DTC is displayed: Go to the next step.
3 | Start the engine and idle it. Turn the A/C switch on. Does 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 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 AC_REQ PID. Start the engine and idle it. Turn the A/C switch on. Does AC_REQ 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 refrigerant pressure switch and PCM terminal 1Q
• Open circuit of blower motor fan switch and resistor (if blower motor does not operate)
• Evaporator temperature sensor and A/C amplifier

5 | Inspect cooling fan control system operation. (See Cooling Fan Motor Operation 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. (See DRIVE BELT REPLACEMENT [ZJ, Z6].)
7 | Is there leakage around heater unit in passenger compartment? | Yes | Inspect and service heater for leakage.
No | Go to the next step.
8 | Is there leakage at 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, Z6].) (See THERMOSTAT INSPECTION [ZJ, Z6].) Is the thermostat normal? | Yes | Engine coolant temperature sensor and the thermostat are normal, inspect the engine block for leakage or blockage.
No | Access ECT PID. Inspect for both 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. • If the temperature gauge on the instrument cluster indicates overheating but ECT PID is normal, inspect the temperature gauge and the heat gauge unit.

10

Verify test results.
• If normal, return to diagnostic index to service any additional symptoms.
(See ENGINE SYMPTOM TROUBLESHOOTING [ZJ, Z6].)
• 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 INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [ZJ, Z6].)