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	What color is the smoke coming from the exhaust system?	Blue	Burning oil is indicated Go to the next step
		White	Water in the combustion is indicated Go to Step 3
		Black	Rich fuel mixture is indicated Go to Step 4
2	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Inspect for the following: Damaged valve guide, stems or valve seals Blocked oil drain passage in the cylinder head Piston ring is not seated, seized or worn Damaged cylinder bore If other driveability symptoms are present, return to the diagnostic index to service any additional symptoms.
2	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [L5] .)
3	Does the cooling system hold pressure?	Yes	Inspect for the following: Cylinder head gasket leakage Intake manifold gasket leakage Cracked or porous engine block If other driveability symptoms are present, return to diagnostic index to service any additional symptoms.
3	Does the cooling system hold pressure?	No	Inspect for cause
4	Inspect for the following. Air cleaner restriction Collapsed or restricted intake air system Restricted fuel return line Are all items normal?	Yes	Go to the next step.
4		No	Service if necessary Repeat Step 4.
5	Connect the M-MDS to the DLC-2 Switch the 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 [L5] .)
5		No	No DTC is displayed: Go to the next step.
6	Inspect the fuel line pressure (See FUEL LINE PRESSURE INSPECTION [L5] .) Is the fuel line pressure correct?	Yes	Go to the next step.
6		No	Low: Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [L5] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [L5] .)
7	Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L5] .) Is a strong blue spark visible at each cylinder?	Yes	Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [L5] .)
7		No	Repair or replace the malfunctioning part according to spark test result.
8	Verify test results If normal, return to the diagnostic index to service any additional symptoms (See SYMPTOM DIAGNOSTIC INDEX [L5] ) If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If the vehicle is repaired, troubleshooting is completed. If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available Retest.