THERE ARE THREE STYLES - A, B and C: BMW first installed the service lights in 1982. At that time the BMW diagnostic connector had 15 pins. In 1987, to add new options they switched to a 20 pin connector. Unfortunately it was not a clean break from the old style. Many 87 and 88's have the 15 pin "old" style connector, as they did not completely phase out the 15 pin connector until late 1988. Lastly, BMW phased out their proprietary connector entirely in 2001 in favor of a standardized 16 pin OBDII connector.

Check the following chart to determine whether you have the "A" style (15 pin) connector or the "B" style (20 pin) connector or the 16 pin "C" style connector.


1982 to 1988

15 pin socket

under hood


1987 to 2000

20 pin socket

under hood.


2000 and later

16 pin socket

under dash


All models built prior to 1987 have "A" style. BMW began phasing-out the A style connector in 1987, and had completely gotten rid of it by the 1989 model year.
The "B" connector was phased-in in 1987, and fully implemented by 1989. Its use was continued until roughly mid-2000.

In the early 1990s the US Government mandated that all passenger cars produced 1996 and later must be equipped with the 16 pin, under dash, "C" style plug.

So BMW complied and just added the "C" connector.

But they kept the "B" connector in models up to 2000 (2003 on the Z3s) meaning many cars have both C and B.

IMPORTANT: If your car has the B connector, you must plug our tools into the B connector in order to enjoy the full range of functions!





If you don't know which style connector your BMW has, read the descriptions below to help you identify your diagnostic connector.

General Locations, Under-Hood: The red squares mark the locations where the diagnostic connector is usually found. Note there is only one diagnostic connector per vehicle.

IMPORTANT NOTE: The diagnostic connector has no wires coming out of the cap.


"A" style 15 pin connector:  Under the hood, usually located on the engine. Most often found on the drivers side (toward the front of the car), high up and readily accessible. It is covered by an oval dust cap which snaps off (can be a little difficult to remove the first time). The dust cap will be red or black. Once the dust cap is removed you will have access to the diagnostic connector. It is shaped like the letter D (round with a flat side, see above). To be sure you have found the correct connector count the number of pin holes, there should be fifteen.

"B" style 20 pin connector:   Under the hood, often located on the engine, shock tower or fire wall, high up and readily accessible. It is covered by a round dust cap which twists off like the lid of a jar (see photo at right). The dust cap is black with a plastic strap attached. (Note: If you find a connector which has wires sticking out of the cap, you have found the wrong connector) Once the dust cap is removed you will have access to the diagnostic connector. To be sure you have found the correct connector count the number of pin holes (20) and observe the center keyway hole which must be shaped like a pie with a piece removed, also referred to as the "PAC-MAN" style plug, named after the character in the PAC-MAN video game of the early eighties. IF YOU FIND A CONNECTOR WITH A TRIANGLE SHAPED HOLE AT THE CENTER, YOU HAVE FOUND THE WRONG ONE!

OBDII Connector (16 pin) found on 2000 and later BMWs:

Starting in 2001, BMW began to phase out the 20 pin B style connector, using only the 16 pin OBDII connector, which we call the "C" or 16 pin connector. Our tools ending in "-16" and the AB03 adaptor are made specifically to accommodate BMWs with the 16 pin OBDII connector. The "C" connector is located under the dash. IMPORTANT: 99% of BMWs built 1996 to 2000 have both the 16 pin "C" / OBD plug shown below, AND the round 20 pin "B" plug shown above. If that is the case, then you must order the tool that plugs into the "B", under-hood connector, otherwise certain tool functions will not work. Only order the -16 tools when the only connector your car has is the "C" connector shown below.

The 16 pin, "C", or OBDII connector.