Diagnostic reader

[genphreak]

I've ordered the cable... I'll keep you guys updated!

Mitch that would be great. Actually, is there any chance that you could post which pins are connected that would be really awesome. I don't think anyone has done this for the BMW diagnostics connector.

Have you a testlight/multimeter to test which pin on the diagnostic plug goes to what pin on the DB9?

I have one like you bought, except that it has no DB9 (instead it has service light reset switches). I'd really like to add a DB9 cable to it so I can avoid buying another one like you have.

Many thanks in advance if you can do this!! Nick

[mitch2k]

Yep, I have the testing equipment, so I'll check it out and let ya know ;-)

[zygoteer]

Interesting. Does this mean you can put 12V down any of the pins without a problem?

The RS232 protocol is based on a + & - voltage swing to give the required data & handshake signals, so provided it is a 'clean' 12V ... then yes.
The reason some systems quote lower, and sometimes single-ended, voltages is simply that they are designed to correctly interpret the signal at those levels, from other equipment that have not implemented the full output spec - their input spec will still cope with the higher levels.

This page is explains most aspects ... http://www.interfacebus.com/Design_Connector_RS232.html , where you will see that the original protocol is tolerant up to +/- 15V, and of course to comply with the spec manufacturers devices will always do better - some marginally, some comfortably.

The car electrical system is often far from 'clean' though, so I use my opto isolator, where I don't have to worry at all, as it takes +/-60V continuous and is protected up to 2000V spikes/transients.

[mitch2k]

Later this week, or next week I'll get the cable.

Is it risky to use without optcoupler? I don't bother if the (old) pc dies, but I don't want to kill my car electronics..

[zygoteer]

Later this week, or next week I'll get the cable.

Is it risky to use without optcoupler? I don't bother if the (old) pc dies, but I don't want to kill my car electronics..

The car is quite tough, it spends all of its life in the same noisy car electrical environment.
Its the laptop that is most vulnerable.

[mitch2k]

I'm using an old desktop pc for this, so I'll take the risk...

[jbourke]

Later this week, or next week I'll get the cable.

Is it risky to use without optcoupler? I don't bother if the (old) pc dies, but I don't want to kill my car electronics..

sounding impatient mitch2k but I was wondering if you received your cable yet? Can't wait for you to post the pinout!

Cheers,

John

[mitch2k]

Today finally got (made) the time for testing the cable...

First I checked the cable. I double checked al connections with the multimeter and it all was right according the pic a few post up from the carsoft manual.

Then I cleared the driveway and drove the bimmer into the garage, and hooked up the cable to the pc and the diagnostic connector.

I Installed the software, putted the com settings right, choosed a diesel type engine, and did the total diagnosis in carsoft.

But too bad, I keep getting a message that the cable is faulty, and that I have to check the connections...

I tried all different ways. Key in off, in position 1, in position 2, and even with running motor. In all these ways I always tried with lights on and lights off..

I did it all over again with my brother's laptop, to be sure it wasn't the PC.

Now on the other hand, I'm not very sure if my car's diagnostic plug is ok..
A while ago, when I've bought the software, the guy showed it to work with his cable.His cable was a cable with a box between the 2 connectors.
But when connecting, the program also gave errors. The guy thought there must be something with my car.. He took the same config to his car, and that worked from the first time. After a while of trying again at my car, and playing with the connectors, It suddenly worked...

I took apart my diagnostic plug, and the connections inside are ok (no loose wires).

No more ideas :-(. Who can help me?

some pics:

[pgrindstaff]

Have you had any more luck with this cable? I've been thinking about getting one then read that yours doesnt work. Are there any options in Carsoft that could be pointing to the wrong com port? Just a guess.

Also, what OBD version do our cars have, OBD1 right? Just noticed that this is an OBD2 cable. That could cause a problem I imagine.

-patrick

[t_marat]

Resurrecting the old thread, but I am really interested if it finally worked or not?
You mention the other guy had a cable with a box in the middle, was it something like this?
http://cgi.ebay.com/ebaymotors/BMW-D...spagenameZWDVW