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HOMESERVICE MANUALSMAZDA20086 S SPORT, 4D HATCHBACK, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 333 (SYMPTOM TROUBLESHOOTING (ENGINE CONTROL SYSTEM AJ))NO. 17 COOLING SYSTEM CONCERNS-OVERHEATINGDIAGNOSTIC PROCEDURE
2008 Mazda 6 s Sport, 4D Hatchback, Standard

Diagnostic procedure

2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION Diagnostic procedure
WARNING: This page is about a different car, the 2005 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
NO. 17 COOLING SYSTEM CONCERNS - OVERHEATING [AJ] DIAGNOSTIC PROCEDURE

STEP INSPECTION 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 okay?
 Yes Go to the next step.
No Service as necessary.
Repeat Step 1.
2
  • Connect WDS or equivalent to DLC-2.
  • Turn ignition switch to ON position (Engine OFF).
  • Retrieve any DTCs.
  • Are there any DTCs displayed?
 Yes DTC is displayed: 
  • Go to appropriate DTC test.
No No DTC is displayed: 
  • Go to the next step.
3
  • Start engine and run it at idle speed.
  • Turn A/C switch on.
  • Does A/C compressor engage?
 Yes Go to step 5.
No Inspect the following and repair or replace as necessary:
  • Refrigerant charging amount
  • Open circuit between A/C relay and PCM terminal 47
  • Seized A/C magnetic clutch
  • A/C magnetic clutch malfunction
    • If all items are okay, Inspect the following:
      • Refrigerant pressure switch operation
      • Evaporator temperature sensor and A/C amplifier
      • A/C switch is stuck open.
      • Open or short circuit between refrigerant pressure switch and PCM terminal 5
      • Open circuit of blower motor fan switch and resistor (if blower motor does not operate)
4
  • Start engine and run it at idle speed.
  • Turn A/C switch on and set blower fan any speed.
  • Do cooling fan and condenser fan operate?
 Yes Go to the next step.
No Cooling fan motor does not operate: 
  • Inspect for following:
    • Cooling fan motor malfunction
    • Cooling fan motor GND open circuit
    • Open circuit between cooling fan motor and fan control module

Condenser fan motor does not operate: 
  • Inspect for the following:
    • Condenser fan motor malfunction
    • Condenser fan motor GND open circuit
    • Open circuit between condenser fan motor and fan control module

Both cooling fan and condenser fan do not operate: 
  • Inspect for the following:
    • Fan control module malfunction
    • Fan control module GND open circuit
    • Open circuit between fan control module and cooling fan relay
5
  • Is drive belt okay?
 Yes Go to the next step.
No Replace drive belt.
6
  • Is there any leakage around heater unit in passenger compartment?
 Yes Inspect and service heater for leakage.
No Go to the next step.
7
  • Is there any leakage at coolant hoses and/or radiator?
 Yes Replace malfunctioning part.
No Go to the next step.
8 Yes Engine coolant temperature and thermostat are okay.
Inspect engine block for leakage or blockage.
No Access ECT PID on WDS or equivalent.
Inspect 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.
9
  • Verify test results.
    • If okay, return to diagnostic index to service any additional symptoms.
    • If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis.
      • If vehicle is repaired, troubleshooting completed.
      • If vehicle is not repaired or additional diagnostic information is not available, reprogram PCM if later calibration is available. Retest.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.