Originally Posted by alxsnmr

1996 was the year mandated for all vehicles to have OBDII except for vehicles above 8300 GVWR (I think that is right). I would have thought your truck would have 3 digit output, but someone said here that it depends on your transmission, i.e. E4OD, AOD-E, 4R70W did have 3 digit codes manuals had 2 digit.