Diagnostic procedure

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DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY SPARK PLUG CONDITION Remove all the spark plugs. (See SPARK PLUG REMOVAL/INSTALLATION .) Inspect the spark plug condition. (See SPARK PLUG INSPECTION .) Are the spark plugs conditions normal?	Yes	Symptom troubleshooting completed.
1		No	Specific plug is wet or covered with carbon: Go to the next step. Specific plug looks grayish white: Go to Step 7. All plugs are wet or covered with carbon: Go to Step 9. All plugs look grayish white: Go to Step 15.
2	DETERMINE IF MALFUNCTION CAUSE IS ENGINE OIL LOSS OR OTHER Are the spark plugs wet/covered with carbon from the engine oil?	Yes	Inspect all areas related to oil, working up and down.
2		No	Go to the next step.
3	INSPECT SPARK PLUG Inspect the spark plugs for the following: Cracked insulator Heat range Air gap Worn electrode Are the spark plugs normal?	Yes	Go to the next step.
3		No	Replace the spark plug. (See SPARK PLUG REMOVAL/INSTALLATION .)
4	INSPECT ENGINE COMPRESSION Inspect the compression pressure at the suspected malfunctioning cylinder. (See COMPRESSION INSPECTION .) Is the compression pressure correct?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part according to the inspection results.
5	INSPECT IGNITION SYSTEM OPERATION Install all the spark plugs. (See SPARK PLUG REMOVAL/INSTALLATION .) Perform the spark test at the suspected malfunctioning cylinder. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Is a strong blue spark visible? (Compare with normal cylinder.)	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part according to the inspection results.
6	INSPECT FUEL LINE PRESSURE Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTOR .) Is the fuel line pressure correct?	Yes	Inspect the fuel injector for the following: Open or short circuit in injector Leakage Injection volume Repair or replace the malfunctioning part according to the inspection results.
6		No	Zero or low: Inspect the following: Fuel pump relay Fuel pump circuit 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 .)
7	INSPECT SPARK PLUG Inspect the spark plug for the following: Heat range Air gap Is the spark plug normal?	Yes	Go to the next step.
7		No	Replace the spark plug. (See SPARK PLUG REMOVAL/INSTALLATION .)
8	INSPECT FUEL INJECTOR OPERATION Perform the Fuel Injector Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Do the fuel injectors operate properly?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to the inspection results.
9	INSPECT AIR CLEANER ELEMENT Is the air cleaner element free of clogging?	Yes	Go to the next step.
9		No	Replace the air cleaner element.
10	INSPECT IGNITION SYSTEM OPERATION Perform the Spark Test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Is a strong blue spark visible at each cylinder?	Yes	Go to the next step.
10		No	Repair or replace the malfunctioning part according to the inspection results.
11	INSPECT FUEL LINE PRESSURE Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTOR .) Is the fuel line pressure correct?	Yes	Go to the next step.
11		No	Zero or low: Inspect the following: Fuel pump relay Fuel pump circuit 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 .)
12	VERIFY CURRENT INPUT SIGNAL STATUS Access the following PCM PIDs: ECT O2S11 (When engine can be started.) O2S12 (When engine can be started.) MAF Are all PIDs normal? (See PCM INSPECTION .)	Yes	Go to the next step.
12		No	ECT PID is not as specified: Inspect for an intermittent open circuit of the ECT sensor and the related wiring harness. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION .) MAF PID is not as specified: Inspect for an intermittent open circuit of the MAF sensor and the related wiring harness. (See MASS AIR FLOW (MAF) SENSOR INSPECTION .) O2S11 PID is not as specified: Inspect for an intermittent open circuit of the A/F sensor and the related wiring harness. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION .) O2S12 PID is not as specified: Inspect for an intermittent open circuit of the HO2S and the related wiring harness. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION .) Repair or replace the malfunctioning part according to the inspection results.
13	INSPECT PURGE CONTROL SYSTEM OPERATION Perform the purge control inspection. (When engine can be started.) (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Is the purge control correct?	Yes	Go to the next step.
13		No	Repair or replace the malfunctioning part according to the inspection results.
14	INSPECT ENGINE COMPRESSION Perform the compression inspection. (See COMPRESSION INSPECTION .) Is the compression correct?	Yes	Visually inspect for deformed exhaust system parts. Repair or replace the malfunctioning part according to the inspection results.
14		No	Repair or replace the malfunctioning part according to the inspection results.
15	INSPECT INTAKE-AIR SYSTEM FOR AIR SUCTION Inspect the following: Intake air system for air leakage (When the engine cannot be started.) Intake manifold vacuum (When the engine can be started.) Is air sucked in from intake air system?	Yes	Repair or replace the malfunctioning part according to the inspection results.
15		No	Go to the next step.
16	INSPECT FUEL LINE PRESSURE Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTOR .) Is the fuel line pressure correct?	Yes	Go to the next step.
16		No	Zero or low: Inspect the following: Fuel pump relay Fuel pump circuit 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 .)
17	VERIFY CURRENT INPUT SIGNAL STATUS Access the following PCM PIDs: ECT O2S11 (When engine can be started.) O2S12 (When engine can be started.) MAF Are all PIDs normal? (See PCM INSPECTION .)	Yes	Inspect the PCM ground condition. Repair or replace the malfunctioning part according to the inspection results.
17		No	ECT PID is not as specified: Inspect for an intermittent open circuit of the ECT sensor and the related wiring harness. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION .) MAF PID is not as specified: Inspect for an intermittent open circuit of the MAF sensor and the related wiring harness. (See MASS AIR FLOW (MAF) SENSOR INSPECTION .) O2S11 PID is not as specified: Inspect for an intermittent open circuit of the A/F sensor and the related wiring harness. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION .) O2S12 PID is not as specified: Inspect for an intermittent open circuit of the HO2S and the related wiring harness. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION .) Repair or replace the malfunctioning part according to the inspection results.
18	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX .) 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.