Diagnostic procedure

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

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
1		No	Service if necessary. Repeat Step 1.
2	Connect the M-MDS to the DLC-2. Switch ignition to ON (Engine off) Retrieve any DTCs. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection (See DTC TABLE [MZI-3.7] .)
2		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.
3		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 1W Seized A/C magnetic clutch A/C magnetic clutch malfunction If all items are normal, go to the next step.
4	Connect the M-MDS to the DLC-2 Access AC_REQ PID Start the engine and idle it Turn the A/C switch and fan switch on Does AC_REQ PID read on?	Yes	Go to the next step
4		No	Inspect the following. Refrigerant pressure sensor operation The A/C switch is stuck open Open or short circuit between refrigerant pressure sensor and PCM terminal 1M Open or short circuit between refrigerant pressure sensor and PCM terminal 1BJ 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 ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does the cooling fan control system function properly?	Yes	Go to the next step
5		No	Repair or replace the malfunctioning part
6	Is there leakage around the heater unit in passenger compartment?	Yes	Inspect and service heater for leakage
6		No	Go to the next step
7	Is there leakage at the coolant hoses and/or radiator?	Yes	Replace the malfunctioning part.
7	Is there leakage at the coolant hoses and/or radiator?	No	Go to the next step
8	Cool down the engine Remove thermostat and inspect operation (See THERMOSTAT REMOVAL/INSTALLATION [MZI-3.7] .) (See THERMOSTAT INSPECTION [MZI-3.7] .) Is thermostat normal?	Yes	The engine coolant temperature and thermostat are normal, inspect engine block for leakage or blockage.
8		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 CHT 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 normal, return to diagnostic index to service any additional symptoms (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) 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 the PCM if a later calibration is available Retest