What is the protocol of the computer on a Ford Aerostar-91 Is it ODB or what?

Answer 1

All cars sold in the US were required by law to have:

OBD 1 during the years from 1980-1996.

OBD 2 was required from 1996-present.

Some manufacturers phazed in OBD 2 early, starting around 1994, but a 1991 Aerostar is definitely OBD 1.

However, the term "protocol" does not refer to the diagnostic requirements, like the term "OBD"(On-Board Diagnostics) does. In other words, OBD is not a protocol. OBD is an emmissions requirement mandated by the EPA. EPA law says you have to have On-Board Diagnostics(OBD) following certain requirements. They had one set of laws that were in effect prior to 1996, which was refferred to as OBD 1. OBD 2 came into effect from 1996 on, but some manufacturers were a litte ahead of the game, and started meeting OBD 2 requirements in 1994 or 1995.

Protocol is a language or platform used by the programmers and engineers. In other words, two OBD systems, of the same year, side-by side, may use a different protocol depending on what their respective manufacturers used. A 1991 Ford and a 1991 Dodge, would not use the same protocol, yet would still meet OBD 1 requirements.

The protocol that a 1991 Aerostar probably used was ISO 9141, but it's diagnostic system would be called OBD 1.

AnswerA shop foreman at your local FORD dealer should be able to answer over the phone..

also...everyone should have a manual for their vehicle, and the local library should have a professional shop manual available, to make copies of, in the Reference section...good luck:)

AnswerThe connector one OBD 1 is located under the hood on the passenger's side attached to the relay box.