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Question -
I have a 98 Ranger with a 4 cyl with a check eng light. Its been on for about 18 mo and its getting close to e-check time. One thing I would like to mention is that it went off for a few days during the winter when it was real cold out. A scanner said it was a large vacuum leak but it still runs fine and my gas mileage has not changed. Anything that you might know of that goes on these after about 75000 mi?
Answer -
What code did the scanner indicate? Their were 3 codes. 444, 445, and 455.
Answer444 and 445 are not on the list of codes. 445 indicates a gross EVAP leak. here is a partial list of things that that can cause this code:
After market parts and accessories nonconforming to the EVAP system specifications.
Damaged, missing or improperly installed fuel filler cap.
Blockage in fuel vapor hoses/tubes (EVAP canister tube, EVAP canister purge outlet tube or EVAP return tube) in EVAP system.
Disconnected or cracked fuel vapor hoses/tubes in EVAP system.
EVAP canister purge valve stuck closed.
Canister vent (CV) solenoid stuck open.
Fuel tank pressure (FTP) sensor malfunction.
EVAP canister leaking.
Fuel vapor control valve tube assembly blocked.
Fuel vapor vent valve assembly blocked.
The most logical is a loose or leaking fuel filler cap, but there are extensive tests to determine the cause if it is not the cap. I have seen many techs struggle with EVAP codes, defintiely not a DYI project. Requires special testing equipment.
