Diagnostic Procedure

STEP	INSPECTION		ACTION
1	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 .)
1		No	Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS NON-RETURN VALVE OR OTHER Remove the fuel-filler pipe. Make sure non-return valve is installed properly. Inspect the non-return valve operation. Is there any malfunction?	Yes	Non-return valve is installed improperly: Reinstall the non-return valve to proper position. Non-return valve does not operate properly: Replace the non-return valve.
2		No	Inspect the following: Improper use of fuel nozzle Inadequate fuel filling speed Repair or replace the malfunctioning part according to the inspection results.
3	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.