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: Vacuum lines for leakage or blockage Electrical connections Proper maintenance schedule followed Intake air system and air cleaner element concerns: obstructions, leakage or soiling 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 the ignition to ON (Engine off). Retrieve any DTCs. Are there any DTCs displayed?	Yes	DTC is displayed: Go to appropriate DTC inspection. (See DTC TABLE [L5] .)
2		No	No DTC is displayed: Go to the next step
3	Is any other driveability concern present?	Yes	Go to appropriate symptom troubleshooting.
3	Is any other driveability concern present?	No	Go to the next step.
4	Connect the M-MDS to the DLC-2. Access the ECT PID. Warm up the engine and idle it. Verify if the ECT PID is correct. (See PCM INSPECTION [L5] .) Is the ECT PID correct?	Yes	Go to the next step.
4		No	Inspect for coolant leakage, and inspect the cooling fan and condenser fan operation or thermostat operation.
5	Inspect the fuel-filler cap (See FUEL-FILLER CAP INSPECTION [L5] .) Is there any leakage at the fuel-filler cap?	Yes	Replace the fuel-filler cap
5		No	Go to the next step
6	Inspect the A/F sensor (See AIR FUEL RATIO (A/F) SENSOR INSPECTION [L5] .) Is the A/F sensor normal?	Yes	Go to the next step.
6		No	Inspect for followings. Exhaust gas leakage between exhaust manifold and A/F sensor. Loose installation of A/F sensor. If there are no malfunctions detected, replace the A/F sensor If there are malfunctions detected, repair or replace malfunctioning part (See EXHAUST SYSTEM 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	Go to the next step
7		No	Repair or replace the malfunctioning part according to the spark test result
8	Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [L5] .) Is the fuel line pressure correct?	Yes	Go to the next step.
8		No	Low: Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. High: Replace the fuel pump unit (See FUEL PUMP UNIT REMOVAL/INSTALLATION [L5] .)
9	Remove and shake the PCV valve Does the PCV valve rattle?	Yes	Go to the next step.
9	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] .)
10	Inspect for fuel saturation inside the charcoal canister. Is there an excess amount of liquid fuel present in canister?	Yes	Replace the charcoal canister (See CHARCOAL CANISTER, CANISTER VENT (CV) SOLENOID VALVE, AIR FILTER COMPONENT REMOVAL/INSTALLATION [L5] .)
10		No	Inspect the fuel tank vent system. Then, go to the next step. (See FUEL TANK INSPECTION [L5] .)
11	Visually inspect the exhaust system parts Are there any deformed exhaust system parts?	Yes	Replace the malfunctioning part.
11		No	Go to the next step
12	Inspect the TWC (See EXHAUST SYSTEM INSPECTION [L5] .) Is the TWC normal?	Yes	Inspect the EGR system (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L5] )
12		No	Replace the TWC. (See EXHAUST SYSTEM REMOVAL/INSTALLATION [L5] .)
13	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.