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HOMESERVICE MANUALSMAZDA20066 I, 4D SEDAN, AUTOMATICREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSISSYMPTOM TROUBLESHOOTING [ENGINE CONTROL SYSTEM L3)NO. 17 COOLING SYSTEM CONCERNS-OVERHEATINGDIAGNOSTIC PROCEDURE
2006 Mazda 6 i, 4D Sedan, Automatic

Diagnostic procedure

2006 Mazda 6 i, 4D Sedan, AutomaticSECTION Diagnostic procedure
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 normal?		 Yes Go to the next step.
No Service if 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 and set blower fan to any speed.
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 between A/C relay and PCM terminal 1I
  • Seized A/C magnetic clutch
  • A/C magnetic clutch malfunction

If all items are okay, go to the next step.
4 Start the engine and run it at idle speed.
Access AC_REQ PID using WDS or equivalent.
Turn A/C switch on and set blower fan any speed.
Does the PID turn ON and OFF properly?
(See PCM INSPECTION ).		 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 1AU
  • 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 CONTROL SYSTEM INSPECTION ).
Does cooling fan control system work properly?		 Yes Go to the next step.
No Repair or replace malfunctioning parts.
6 Is drive belt normal? Yes Go to the next step.
No Replace drive belt.
7 Is there any leakage around heater unit in passenger compartment? Yes Inspect and service heater for leakage.
No Go to the next step.
8 Is there any leakage at coolant hoses and/or radiator? Yes Replace malfunctioning part.
No Go to the next step.
9 Cool down the engine.
Remove thermostat and inspect operation.
(See THERMOSTAT REMOVAL/INSTALLATION ).
(See THERMOSTAT INSPECTION ).
Is thermostat normal?		 Yes Engine coolant temperature and thermostat are okay, 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 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.