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OBD Diagnostic Codes

What are the OBD-II pins?

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2015-07-17 17:46:40

"Honda_Man's" id="Honda_Man's">Honda Man's

Since we don't know what make, model or year your car is, this is a

difficult question. If it is in fact OBD II, the connector should

be located under the driver's side dash.

In order to find your codes, you don't need to plug into the

obd2 port. On the bottom right side of the diagnostic port, there

should be two pins rather close together. My recommendation is to

go to Auto Zone. Some of their stores actually have a key for

checking GM obd1 systems. It looks like a key, and has two prongs

on it that plug right in to where you need to check your codes. If

your local store does not have one, then my advice is to look on

the port and find the two bottom prongs that are closest together

and jump them.

I have the exact same pinout on my 1995 Buick LeSabre. I have

been researching this issue for some time now. The VECI label abve

the radiator in my car states "OBD 1 Certified." However, I believe

this is only stated because the pinouts of the connector are wrong.

I have the VIN L engine, and all technical docs for that engine

point to it being controlled by a PCM. PCMs do not report codes by

flashing the SES light, only GM ECMs do. GM cars with an ECM and a

16-pin J1850 non-OBD-II connector on them, have a pin-out of

4,5,6,9,12,16. You short pins 5 and 6 to receive diagnostic trouble

codes via the Service Engine Soon light. As you can see, those pins

do not light up with our common connectors. Our connectors use pins

4,5,8,9,14,16. What I can tell you about this connector is as

follows: 4=Chassis Ground, 5=Signal Ground, 8=Keyless RF Trigger

(short to 5 to enter program mode), 16=Battery+. (Note 4,5=Ground

16=Battery+ are standard pins for the OBD-II standard. Yet another

thing that points to an OBD-II serial uplink.) 1995 was a

transition year for GM, in many different aspects including OBD-II.

I believe what happened, what the pins were installed in one order

believing that they conformed to standard, and then the standard

changed before finalization. For more information on this, check

out my regular posts to Automotive in the Buick LeSabre

forum. This is my latest:

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