Hi All.. hoping someone has had this issue and can help me. I have several Preludes of different years. The one giving me the grief right now is an 01 SH. It keeps throwing a code 91 which indicates FTP sensor. It has no FTP sensor. It has an evap flow switch which I have changed.. cleared codes.. it ran for 2 days with no cel or atts lights on. They're back on now. The worst part is of course that the ATTS doesn't work when the cel light is on.


My confusion is.. I have a 98 SH that has an ftp sensor... a 2001 base that has an ftp sensor and a 2001 SE that has an ftp sensor. Why is this the only car that has this switch and what could be the issue that it won't stay working? I've changed all the evap hoses also.