Hi Numan. I reckoned it would be U answering, if any.
I've done some investigation since I posted the topic, and found out that the 156 prolly not are capable of OBDII diagnosis. The OBDII has 3 different protocols with different layout of the connector.
J1850 VPW--The connector should have contacts in pins 2, 4, 5, and 16, but not 10.
ISO 9141-2--The connector should have contacts in pins 4, 5, 7, 15, and 16.
J1850 PWM--The connector should have contacts in pins 2, 4, 5, 10, and 16.
None of these fit the 156.
As for the EOBD, the layout is also different from the 156. The above picture shows the layout of pins, and does not match those of my 156 either.
If you by any chance can findout the layout of the pins on the 156, especially the location of the K and L line and com. ground, I would very much appreciate it. I could fabricate an adapter then, and hook up our workshop tester.
One thing both EOBD and OBD-II have in common though is the powersupply. Ground at pin 4 and power(30) at pin 16.
Hoygaard (Honda expert technician)
PS. Sorry if I bore the rest of U guys with this MumbleJumble.