Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.

ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES - DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	Verify following: Vacuum connection Air cleaner element No air leakage from intake-air system No restriction of intake-air system Proper sealing of intake manifold and components attached to intake manifold: EGR valve, IAC valve Ignition wiring Fuel quality: proper octane, contamination, winter/summer blend Electrical connections Smooth operation of throttle valve Are all items okay?	Yes	Go to next step.
1		No	Service as necessary. Repeat Step 1.
2	Connect WDS or equivalent DLC-2. Turn ignition key to ON (Engine OFF). Retrieve any DTCs. Is "PASSED" displayed?	Yes	No DTC is displayed: Go to next step.
2		No	DTC is displayed: Go to appropriate DTC test.
3	Is engine overheating?	Yes	Go to symptom troubleshooting in NO.17 COOLING SYSTEM CONCERNS-OVERHEATING .
3	Is engine overheating?	No	Go to next step.
4	Connect WDS or equivalent to DLC-2. Access RPM, MAF and TP PIDs. Drive vehicle with monitoring PIDs. Are PIDs within specification? (See PCM INSPECTION USING THE SST (WDS OR EQUIVALENT) .)	Yes	Go to next step.
4		No	RPM PID: Inspect CKP sensor and related harness for vibration and/or intermittent open/short circuit. MAF PID: Inspect for open circuit of MAF sensor and related wire harness intermittently. TP PID: Inspect if output signal from TP sensor changes smoothly. VSSPID: Inspect for open circuit of VSS and related wire harness intermittently.
5	Visually inspect CKP sensor and teeth of crankshaft pulley. Are CKP sensor and teeth of crankshaft pulley okay?	Yes	Go to next step.
5		No	Replace malfunctioning part.
6	Inspect spark plug conditions. Is spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Inspect for fuel leakage from fuel injector. Inspect ignition system for suspect cylinder. Spark plug is grayish white: Inspect for clogged fuel injector.
6		No	Install spark plugs on original cylinders. Go to next step.
7	Remove and shake PCV valve. Does PCV valve rattle?	Yes	Go to next step.
7	Remove and shake PCV valve. Does PCV valve rattle?	No	Replace PCV valve.
8	Inspect that throttle lever is resting on throttle valve stop screw and/or throttle valve orifice plug Is lever in correct position?	Yes	Go to next step.
8		No	Replace throttle valve body.
9	Inspect for restriction in the exhaust system. Is there any restriction?	Yes	Inspect exhaust system.
9		No	Go to next step.
10	Install fuel pressure gauge between pulsation damper and fuel distributor. Connect jumper wire between F/P terminal at DLC in engine compartment and GND. Turn ignition key to ON (Engine OFF). Is fuel line pressure correct with ignition key at ON? Fuel line pressure 420-460 kPa {4.3-4.6 kgf/cm2, 61-66 psi}	Yes	Go to next step.
10		No	Zero or low: Inspect fuel pump circuit. Inspect for open fuel pump relief valve. Inspect for fuel leakage inside pressure regulator. Inspect for clogged main fuel line. High: Inspect pressure regulator for high pressure cause. Inspect for clogged fuel return line.
11	Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service as necessary. Does fuel line pressure hold after ignition key is turned OFF?	Yes	Go to next step.
11		No	Inspect pressure regulator diaphragm condition. If condition is okay, inspect fuel injector. If condition is not okay, replace pressure regulator.
12	NOTE: Following test is for engine stall with A/C on. If other symptom exists, go to next step. Connect a pressure gauge to A/C low and high pressure side lines. Turn A/C on and measure low side and high side pressures. Are pressures within specifications? (See REFRIGERANT PRESSURE CHECK .)	Yes	Go to next step.
12		No	If A/C is always on, go to symptom troubleshooting in NO.24 A/C ALWAYS ON/A/C COMPRESSOR RUNS CONTINUOUSLY . For other symptoms, inspect following: Refrigerant charging amount Condenser fan operation
13	NOTE: Following test is performed for symptom with cruise control on. If other symptom exists, go to next step. Inspect cruise control system. Is cruise control system okay?	Yes	Go to next step.
13		No	Repair or replace malfunctioning part.
14	Disconnect vacuum hose between purge solenoid valve and intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Drive vehicle. Does engine condition improve?	Yes	Inspect if purge solenoid valve is stuck open mechanically. Inspect EVAP control system.
14		No	Go to next step.
15	Visually inspect CMP sensor and projections of camshaft pulley. Are CMP sensor and projections of camshaft pulley okay?	Yes	Go to next step.
15		No	Replace malfunctioning parts.
16	Inspect EGR system. Is EGR system okay?	Yes	Go to next step.
16	Inspect EGR system. Is EGR system okay?	No	Replace malfunctioning parts.
17	Is engine compression correct? (See COMPRESSION INSPECTION .)	Yes	Inspect following: Valve timing Internal transaxle part
17		No	Inspect for cause.
18	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, replace or reprogram PCM.