455 code where to start
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Joined: May 2004
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455 code where to start
I have a 98 explorer XLT with a check engine light. The code is 455. Any ideas where to start? As background I have just had the tranny rebuilt a week before the check engine light came on. Thanks
Elder User
Joined: Sep 2006
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Being this system is OBDII it is required by law to monitor all of it's own emissions. Since a fuel leak technically is an emission (HydroCarbons) the EVAP system was developed to test that.
It pulls vacuum on your fuel tank.. and then measures that vacuum for awhile to make sure it holds. If it does not hold vacuum, it sets a code. This can be caused by.. leaving the gas cap off, bad gas cap, hole in tank or vacuum lines (typically a fuel VAPOR leak.. not so much a liquid leak), or a disconnected or failed EVAP component.
Best I can tell you is buy a new gas cap (not a locking type as those tend to leak) have the code cleared and drive for awhile.. if the code comes back I highly recommend taking it to a professional, as these can be a S.O.A.B. to diagnose.. I've had many I've actually had to use an EVAP APPROVED smoke machine on to find the leak. Also had some intermittant purge valve failures which weren't closing off the system properly prior to the computer running its evap test and 'fooling' it into thinking there was a leak.
Good luck
It pulls vacuum on your fuel tank.. and then measures that vacuum for awhile to make sure it holds. If it does not hold vacuum, it sets a code. This can be caused by.. leaving the gas cap off, bad gas cap, hole in tank or vacuum lines (typically a fuel VAPOR leak.. not so much a liquid leak), or a disconnected or failed EVAP component.
Best I can tell you is buy a new gas cap (not a locking type as those tend to leak) have the code cleared and drive for awhile.. if the code comes back I highly recommend taking it to a professional, as these can be a S.O.A.B. to diagnose.. I've had many I've actually had to use an EVAP APPROVED smoke machine on to find the leak. Also had some intermittant purge valve failures which weren't closing off the system properly prior to the computer running its evap test and 'fooling' it into thinking there was a leak.
Good luck
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Warren Hart
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Sep 30, 2016 06:35 AM
