i keep getting code p0102 . when i check at plug i have power in middle at #2. however i have no ground at plug what so ever . i was hoping some one would be able to tell me witch wire was suppose to be ground and the end point of were it is. so i can check the continuity in wire . the Bentley wiring diagram i found online tells me that the black with blue tracer goes to 256 . but i do not know what 256 is . the green wire shows it just going to bar looking thing . but know final destination . maybe i am missing something in that diagram but it makes no sense to me . any help would be great thanks.