Diagnostic Procedure

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY IF THERE IS DRIVEABILITY MALFUNCTION OR EXHAUST GAS MALFUNCTION Are any drivability or exhaust smoke concerns present?	Yes	Go to the appropriate flow chart.
1		No	Go to the next step.
2	INSPECT RELATED PART CONDITION Inspect the following: Electrical connections Fuel quality Vacuum lines Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 2.
2		No	Go to the next step.
3	VERIFY PCM DTC Perform the PCM DTC inspection using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
3		No	Go to the next step.
4	INSPECT FUEL LINE PRESSURE Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION .) Is there any malfunction?	Yes	Zero or low: Inspect the fuel pump relay and the fuel pump circuit. (See RELAY INSPECTION .) Inspect the fuel line for restriction. If there is any malfunction: Repair or replace the malfunctioning part according to the inspection results. If there is no malfunction: Replace the fuel pump unit. (Pressure regulator or fuel pump malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION .)
4		No	Go to the next step.
5	DETERMINE IF MALFUNCTION CAUSE IS CHARCOAL CANISTER OR FUEL TANK VENT SYSTEM Inspect the charcoal canister for fuel saturation. Is an excess amount of liquid fuel present in the canister?	Yes	Replace the charcoal canister. (See CHARCOAL CANISTER REMOVAL/INSTALLATION .)
5		No	Inspect the fuel tank vent system. If the fuel tank vent system is not normal: Repair or replace the malfunctioning part according to the inspection results. If the fuel tank vent system is normal: Suggest trying a different brand since the sulfur content can vary in different fuels.
6	Verify test results. If normal, return to the diagnostic index to service any additional symptoms. (See ENGINE CONTROL SYSTEM SYMPTOM DIAGNOSTIC INDEX .) 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.