Hi,
I own and drive a rather rare car, and finding a original diagnostic instrument is practically impossible.
I have managed to locate and borrow one such instrument, and would like to dublicate parts of the simple functions - values reporting etc.

So I wonder - would I be able to use the "KL-Interface B (serial)" to monitor the communication between the original diagnostic instrument and the car? If yes, which software would be best for that task? And would it be enough with simple Y parallel connection to the existing cable connecting the car with the original diagnostic instrument be sufficient?

According to the car service manual all the ECUs in the car have a K and an L line. All the ECUs K and L lines have their own pins on the OBD connector, but the cable to the diagnostic instrument just connects all K lines to one “common” K line and all L lines to one “common” L line.

I have tried searching the forums, but my limited knowledge of German is not enough to find any meaningful info.

Best regards,
Nik

It should be possible to monitor the communication with a KL interface on the "common" K and L line. Just try it with a terminal program like HTerm.

Thank you Florian!

I assembled the KL serial kit, made a Y cable and connected both the K and L line in parralel with the car - diagnostic instrument cable. Then used the HTerm program to log the communication. It all seems very logical... but I am unable to make any sense of it though. I tried reading all on your site regarding KL communication, with no clue. I managed to log this with 9600 setting for the serial port - could not select 10400.. Is it possible that the data is flowing with 10400 and I am basically getting garbage with my com port set to 9600?

The following is logged after requesting a specific set (Amper -2A, Volt 121V, Degrees 12C, Degrees 13C, Volt 14V, percent 80%, percent 30%, and five bits - yes and no) of parameters. I suppose that every 10 bytes message (or frame) contains all the parameters:
19:17:52.753:
8C8AFBD02B8C0315D283
19:17:52.964:
829395
19:17:53.294:
8CAAFFD02B8C03159297
19:17:53.495:
82D395
19:17:53.845:
8CAAFFD02B8C43159297
19:17:54.045:
82D395
19:17:54.396:
8C8AFFD02B8C0315921D
19:17:54.596:
82D395
19:17:54.947:
8C8AFFD02B8C0315923D


The following is the initialization:
19:17:43.050:
00
19:17:43.650:
00
19:17:44.452:
00
19:17:45.273:
95
19:17:45.323:
C4
19:17:45.363:
87
19:17:46.134:
82B1B3
19:17:46.464:
828CE6
19:17:50.280:
82B6B8
19:17:50.620:
8213FE
19:17:52.403:
829395