YOUCANIC BMW 20 Pin Round Connector to OBD2 Adapter Cable for 1988 to 2001 BMW E30, E34, E36, E38, E39, E46, Z3, X5, for UCAN-II Pro Scanner
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Older BMW With A Round Socket Under The Hood? This Connects Your Scanner To It.
BMWs built from the late 1980s until about 2000, a few models into 2001, talk to a scanner through a round 20 pin socket in the engine bay, not the 16 pin OBD2 port under the dash. This adapter puts the UCAN-II Pro on that socket so you can read and clear every control unit the car has: engine, transmission, ABS, airbag, instrument cluster, climate, immobilizer and more.
The Plug Is The Easy Part
This cable changes the shape of the plug and carries power and data between the car and the scanner. It does not teach a scanner to speak BMW. A generic OBD2 code reader will not read a 1995 E34 through it, because those cars use BMW's own diagnostic language, not the universal OBD2 protocol. The UCAN-II Pro and the UCAN-II carry BMW coverage for these years, and this adapter is wired for them. Other scanner brands wire their 20 pin adapters for their own tools, so if you run a different scanner, buy that brand's adapter.
One more honest note: on the oldest cars, roughly 1988 to 1994, how much the scanner can reach depends on the control units in that car as much as on the scanner. If you have one of those and want to be sure before you order, email the year, model and engine to support@youcanic.com and we will tell you.
Does Your BMW Need It? Open The Hood.
Look along the engine bay, usually on the driver side near the firewall or the strut tower, for a round black screw cap about an inch and a half across. Under that cap is a ring of 20 pins. If your car has it, you need this adapter for anything beyond engine codes. If there is no round socket and the only diagnostic port is the 16 pin one under the dash, your car was built after the changeover and the scanner plugs straight in.
| BMW | Years with the round socket | Note |
|---|---|---|
| 3 Series E30 | 1988 to 1992 | Late production cars; earlier E30s have no diagnostic socket |
| 3 Series E36 | 1992 to 1999 | 1996 and newer also have a dash port, engine only |
| 3 Series E46 | 1999 to 2000 | Built through about September 2000; later E46 use the dash port for everything |
| 5 Series E34 | 1989 to 1995 | |
| 5 Series E39 | 1996 to 2000 | Built through about September 2000 |
| 7 Series E32 | 1988 to 1994 | |
| 7 Series E38 | 1995 to 2001 | Keeps the round socket to the end of production |
| 8 Series E31 | 1991 to 1997 | |
| Z3 (E36/7, E36/8) | 1996 to 2000 | Check under the hood on 2001 and 2002 cars |
| Z8 E52 | 2000 to 2001 | |
| X5 E53 | 2000 and some early 2001 builds | Dropped around the September 2000 build date |
Two ports, 1996 to 2000: these cars have both the round socket and a 16 pin port under the dash. The dash port exists for emissions testing and usually reaches the engine computer and little else. ABS, airbag, cluster, transmission, climate and the rest answer only at the round socket. If your scanner sees just one module through the dash port, that is why.
How To Connect
- Ignition on, engine off. The socket is powered with the key in the run position.
- Unscrew the round cap on the socket in the engine bay.
- Push the adapter's round plug on. It is keyed and goes on one way; turn it until it seats, do not force it.
- Plug your scanner's VCI or cable into the adapter's 16 pin OBD2 socket. It powers up from the car through the adapter.
- On the scanner, pick BMW, the chassis and the module, then read, clear and watch live data as usual.
- Screw the cap back on properly when you are done. On many of these cars the cap bridges two pins that the dash port depends on. A missing or crooked cap is a common reason the OBD2 port under the dash goes silent.
From An Owner
"Great 20 pin adapter for BMW Z3. Works wonderful on my Z3."
Specifications
| Part | BMW 20 pin round diagnostic socket to 16 pin OBD2 adapter cable, with an auxiliary 12 V lead |
| Fits | BMWs with the round 20 pin socket in the engine bay, roughly 1988 through 2000 production and a few models into 2001 (table above) |
| Works with | UCAN-II Pro and UCAN-II scanners |
| Not for | BMWs built from about September 2000 on, which have no round socket (the scanner plugs into the dash port directly); Mercedes with the round 38 pin socket, which need the 38 pin adapter instead |
| Power | From the vehicle socket; auxiliary 12 V lead for the rare car that does not supply it |
| In the box | One adapter cable |
| Weight | About 0.3 lb |
| Warranty and returns | 1 year YOUCANIC warranty, 31 day returns, US based support from Towson, Maryland |
Frequently Asked Questions
Will this let a basic OBD2 code reader read my 1995 E34?
No. The cable only changes the plug. A pre 1996 BMW speaks BMW's own diagnostic protocol, and a generic code reader does not understand it. You need a scanner with BMW coverage for those years, such as the UCAN-II Pro.
My 1998 E36 has an OBD2 port under the dash. Why would I need this?
On 1996 to 2000 BMWs the dash port was added for emissions testing and usually reaches the engine computer only. ABS, airbag, instrument cluster, transmission and the other modules answer at the round socket under the hood. Use the dash port for a quick check engine light read and the adapter for everything else.
Where is the round socket?
In the engine bay, in most cases on the driver side near the firewall or the strut tower, under a round black screw cap. On some models it sits further forward near the fender. It is the only round capped socket in the bay, so it is hard to miss once you look for it.
Does the UCAN-II Pro cover these BMWs?
Yes. The UCAN-II and UCAN-II Pro carry BMW coverage for these model years, and this adapter is wired for them. On the oldest cars the number of control units that can talk is small, which is the car's doing rather than the scanner's. Email us the year, model and engine if you want it confirmed before you order.
What is the small extra connector on the cable?
A 12 V power lead for the scanner. Leave it unplugged unless the scanner fails to power up through the socket, then connect it to the battery positive terminal or another 12 V source.
Will it work on my 2002 E46 or 2003 Z4?
No, and you do not need it. Those cars have no round socket. Plug the scanner into the 16 pin port under the dash and it reaches every module.
Is this the same thing as the Mercedes 38 pin adapter?
No. Older Mercedes use a larger round 38 pin socket and a different adapter. The BMW socket has 20 pins. If you work on both, you need both adapters.
What does the warranty cover?
1 year against defects, honored by YOUCANIC in Towson, Maryland. Email support@youcanic.com or call 1-888-959-4265 with your order number.
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