Diagnostic Procedure

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Verify the following: Vacuum connection Restriction in intake air system (such as air cleaner element, fresh air duct) No air leakage from intake air system No restriction of intake air system Proper sealing of intake manifold and components attached to intake manifold; such as EGR valve Fuel quality (such as proper octane, contamination, winter/summer blend) Are all items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	Connect the WDS or equivalent to the DLC-2. Turn the ignition switch to the ON position (Engine off). Retrieve any DTCs. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE ).
2		No	No DTC is displayed: Go to the next step.
3	Is the engine overheating?	Yes	Go to symptom troubleshooting "NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING ".
3	Is the engine overheating?	No	Go to the next step.
4	Connect the WDS or equivalent to the DLC-2. Access APP1, APP2, RPM, MAF, TP, IAT and VSS PIDs. Drive vehicle while monitoring PIDs. Are PIDs within specifications? (See PCM INSPECTION ).	Yes	Go to the next step.
4		No	APP1, APP2 PIDs: Inspect if output signal accelerator pedal position sensor changes smoothly. RPM PID: Inspect CKP sensor and related wiring harness for vibration or intermittent open/short circuit or both. MAF PID: Inspect for intermittent open circuit of MAF sensor and related wiring harness. TP PID: Inspect if output signal TP sensor changes smoothly. IAT PID: Inspect for air suction in intake air system. If normal, inspect intermittent short circuit of IAT sensor and related wiring harnesses. VSS PID: Inspect for intermittent open circuit of VSS and related wiring harness.
5	Visually inspect the CKP sensor and teeth of crankshaft pulley. Are the CKP sensor and teeth of crankshaft pulley normal?	Yes	Go to the next step.
5		No	Replace the malfunctioning part.
6	Inspect the spark plug condition. Is spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Inspect the fuel injector for fuel leakage. Inspect spark plug and high-tension lead. Spark plug Is grayish white: Inspect the fuel injector for clogging.
6		No	Install the spark plugs on original cylinders. Go to the next step.
7	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
7	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace PCV valve.
8	Perform electronic throttle control system operation inspection. (See ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION ). Does electronic throttle control system function properly?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to electronic throttle control system operation inspection results.
9	visually inspect deformed exhaust system part. Is there any deformed exhaust system part?	Yes	Replace the suspected part.
9		No	Go to the next step.
10	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Connect the WDS or equivalent to DLC-2. Turn the fuel pump on using FP PID in output state control of data logger function. Is fuel line pressure correct? (See FUEL LINE PRESSURE INSPECTION ).	Yes	Go to the next step.
10		No	Zero or low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION ). High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION ).
11	Inspect variable tumble control operation. (See VARIABLE TUMBLE CONTROL OPERATION INSPECTION ). Does variable tumble control function properly?	Yes	Go to the next step.
11		No	Repair or replace the malfunctioning part.
12	Inspect variable intake air control operation. (See VARIABLE INTAKE AIR CONTROL OPERATION INSPECTION ). Does VIS function properly?	Yes	Go to the next step.
12		No	Repair or replace the malfunctioning part.
13	NOTE: The following test is for engine stalling with the A/C on concern. If other symptoms exist, go to the next step. Connect pressure gauge to the A/C low and high side pressure lines.Turn the A/C on and measure low side and high side pressures.Are pressures within specifications?(See REFRIGERANT PRESSURE CHECK ).	Yes	Go to the next step.
13		No	If A/C is always on, go to HEATER, VENTILATION & AIR CONDITIONING (HVAC) -- SYMPTOM TROUBLESHOOTING . "No.24 A/C is always on or A/C compressor runs continuously". (See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY ). For other symptoms, inspect the following: Refrigerant charging amount Condenser fan operation
14	Inspect for A/C cut-off operation. (See A/C CUT-OFF CONTROL SYSTEM INSPECTION ). Does the A/C cut-off function properly?	Yes	Go to the next step.
14		No	Inspect A/C cut-off system components.
15	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Inspect if purge solenoid valve is stuck open mechanically. Inspect the evaporative emission control system. (See PURGE CONTROL SYSTEM INSPECTION ).
15		No	Go to the next step.
16	Visually inspect the CMP sensor and projections of camshaft pulley. Are the CMP sensor and projections of camshaft pulley normal?	Yes	Go to the next step.
16		No	Replace the malfunctioning part.
17	Inspect EGR system. (See EGR CONTROL SYSTEM INSPECTION ). Is EGR system normal?	Yes	Go to the next step.
17		No	Replace the malfunctioning part according to EGR control system operation inspection results.
18	Inspect the variable valve timing control system operation. (See VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION INSPECTION ). Does the variable valve timing control system function properly?	Yes	Go to the next step.
18		No	Repair or replace the malfunctioning part according to variable valve timing control system inspection results.
19	Is the engine compression correct?	Yes	Inspect the following: Valve timing Internal transaxle components (ATX) Clutch (MTX) Brake system for dragging
19	Is the engine compression correct?	No	Inspect for cause.
20	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING ). 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 the PCM. (See PCM REMOVAL/INSTALLATION ).