OBD-2 Protocol identification/information

[Shaman]

I am trying to learn more about OBD-2, and finally got under my dash to get a pic



I am seeing plugs in 1,4,6,7,8,9,13, and 16. The car is a 1999, and supposedly OBD-2 isn't supported until 2000 in Japan. is it normal to have an OBD-2 port without OBD-2? What can a multimeter tell me about my port, and identifying the protocol?

 

[brianl703]

Originally Posted By: Shaman
The car is a 1999, and supposedly OBD-2 isn't supported until 2000 in Japan.


If anything, it did not become mandatory in Japan until 2000. Prior to then, a manufacturer had the option to implement OBD-II or not. I suspect that quite a few did simply because it was mandatory in the USA. Standardizing on a diagnostic protocol saves money in the long run. So the port under your dash may well be an OBD-II port.

 

[Shaman]

How do I go about figuring out the protocol

 

[brianl703]

If it really is OBD-II, the protocol is almost certain to be ISO.

 

[mechtech2]

Just plug in a code reader and see what happens.

 

[GMBoy]

It doesn't matter what they did in Japan in 1999. The fact that your car is a USA spec'd model it is mandated to be OBD2. Any vehicle 1996 and newer is OBD2.

 

[Shaman]

It does, because my car was built in Japan for the Japanese market.

Registered: 07/28/04
Posts: 2013
Loc: Mito, Japan

 

[GMBoy]

Originally Posted By: Shaman
It does, because my car was built in Japan for the Japanese market.

Registered: 07/28/04
Posts: 2013
Loc: Mito, Japan



My mistake.

To answer your question, yes some cars did have an OB2 port before actually being OBD2. For example, I have a 1994 Corvette. It has an OBD2 port but is mostly OBD1..with some OBD2 functionality. This was GM's tryout phase in preparing for OBD2. They did this also with the Buick Park Ave in 1995.

 

[brianl703]

Your port should have grounds in pin 4 and/or pin 5 to be OBD-II.

http://www.auterraweb.com/obdiipinout.html

Based on the data pins you have, it is using ISO protocol, but if there's no ground in pin 4 or 5 then there is no telling what you have.

 

[Shaman]

The car is getting a CV joint replaced, but I will check it when I get it back. Looking at a pic from the back, the 4 pin is black and white, and 16 is red and yellow,so we will see when I get it back. The site seems to show that all grounds are pin 5, are 4 and 5 interchangeable?

 

[brianl703]

There should be grounds in both 4 and 5 according to the spec, but a ground in only 5 would still allow it to work.

 

[The_Jeff]

Most scan tools I've played with internally jumper 4 & 5.