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 for 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 dirtiness 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 appropriate DTC inspection. (See DTC TABLE [MZI-3.7] .)
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 ECT PID. Warm up the engine and idle it. Verify ECT PID is correct. (See PCM INSPECTION [MZI-3.7] .) Is ECT PID correct?	Yes	Go to the next step.
4		No	Inspect for coolant leakage, cooling fan and condenser fan operation or thermostat operation
5	Inspect fuel-filler cap. (See FUEL-FILLER CAP INSPECTION [MZI-3.7] .) Is there any leakage at 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 [MZI-3.7] .) Is A/F sensor normal?	Yes	Go to the next step.
6		No	Inspect A/F sensor installation and exhaust gas leakage, service if necessary. If there is no malfunction, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZI-3.7] .)
7	Perform spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step
7		No	Repair or replace the malfunctioning part according to spark test result
8	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start the engine and idle it. Measure fuel line pressure during idle. Is fuel line pressure correct during idle? (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] .)	Yes	Go to the next step.
8		No	Low: Perform "Fuel Pump Operation Inspection" and "Fuel Pump Control System Operation Inspection", repair or replace according to inspection results. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] .) High: Perform "Fuel Pump Operation Inspection" and "Fuel Pump Control System Operation Inspection", repair or replace according to inspection results. If there is no malfunction, replace the fuel pump unit (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] .)
9	Inspect for fuel saturation inside charcoal canister. Is excess amount of liquid fuel present in canister?	Yes	Replace the charcoal canister.
9		No	Inspect the fuel tank vent system. Then, go to the next step. (See FUEL TANK INSPECTION [MZI-3.7] .)
10	Visually inspect the exhaust system part Is there any deformed exhaust system part?	Yes	Replace the part
10		No	Go to the next step.
11	Inspect the three-way catalytic converter (See EXHAUST SYSTEM INSPECTION [MZI-3.7] .) Is the three-way catalytic converter normal?	Yes	Inspect the PCV valve.
11		No	Replace the three-way catalytic converter.
12	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.