ODB-II code series PO7xx is global transmission. PO753 is probably a shift solenoid, but it depends on the specific car.
Trouble code P0251 means:Injection pump A rotor/cam malfunction
show me
Trouble code P0000 means: No Fault Found
P0139 02 Sensor Circuit Slow Response (Bank 1 Sensor 2)
Very simple, actually I just did it, the ODBII port is directly under the steering wheel where the carpet and trim meet.
Underneath dash driver side
Are you sure about that code? I'm not seeing it in the ODBII code list. http://autorepair.about.com/od/obdcodedatabase/a/OBD_1996_year.htm
No, the 1999 model is equipped with ODB I
Its in the fuse box under the steering wheel looks to be a standard odbII
Under the dash, on the driver's side.
I wasn't aware that vehicles older then '91 had ODBI or ODBII diagnostics.
Replace airpump check valve on passenger side of secondary air system.