OBD1 pin out & OTC Nemisys question

[EDZIP]

Noticed that my OTC Nemisys won't communicate with a Chevy 1991 G30 van or 1989 vette...it communicates with my buddies 94 K1500 no problem. The OBD1connectors have different pin outs...anyone run into this problem?


Anyone with a OTC Nemisys:

Since I upgraded my OTC Nemisys cartridge neither the internal or external power source indicators light come on. The unit still works...also having trouble communicating with the OBD1 vehicles noted above..is fine with OBD2.

[1project2many]

Ever have this problem? Yep... many times. GM even had a special "L to M" adapter for the Tech 1.

[EDZIP]

Ever have this problem? Yep... many times. GM even had a special "L to M" adapter for the Tech 1.

Do you just re-pin the connector on each occasion? Or is there a generic OBD1 to OBD1 adapter?

[steveo]

bet a couple o homemade spade jumpers male to female about 4" long really does the trick

I just kept a pair with my obd1.5 cable to use with obd1 stuff

[1project2many]

I didn't need to repin anything. GM had a special adapter. My bad, though. It was E to M not L to M.
bsh-2001244.gif

http://www.etoolpros.com/automotive-...-02001244.html

I got my own when I picked up an old Techline terminal from a dealership. You could just use jumpers, though.

[EDZIP]

I didn't need to repin anything. GM had a special adapter. My bad, though. It was E to M not L to M.
bsh-2001244.gif

http://www.etoolpros.com/automotive-...-02001244.html

I got my own when I picked up an old Techline terminal from a dealership. You could just use jumpers, though.

Have an idea of how many different pin configurations GM made for the OBD1 connectors? I have one of these OBD1 to OBD2 adapters that could be separated. Could wire up the male end up to a female connector.

Will just check the wiring tomorrow on the adapter...it might be OK as is? My 1995 S10 pickup has the OBD2 (J1962) connector (like the 95 Camaros) and my OTC scanner plugs right in without external power in the OBD1 mode.

[1project2many]

Have an idea of how many different pin configurations GM made for the OBD1 connectors?

A, B, and at least one data line used always. E is 160 baud for older ecms. M is 8192 baud. IIRC K was ABS for some models, and maybe C was entertainment and cruise for high end Olds/Buick/Caddy systems (Robert would probably know this one better). I don't remember seeing any vehicle with all pins populated.

1995 S and T trucks had halfway implemented OBDII standard. Some OBDII scantools will get codes, some not. We have 2010 one ton vans here with no 12V line at the OBDII connector. Can't use cheapie scantools to get codes.

[EDZIP]

A, B, and at least one data line used always. E is 160 baud for older ecms. M is 8192 baud. IIRC K was ABS for some models, and maybe C was entertainment and cruise for high end Olds/Buick/Caddy systems (Robert would probably know this one better). I don't remember seeing any vehicle with all pins populated.

1995 S and T trucks had halfway implemented OBDII standard. Some OBDII scantools will get codes, some not. We have 2010 one ton vans here with no 12V line at the OBDII connector. Can't use cheapie scantools to get codes.

Looking at my working TPI harness in my 33 Chevy, Pins E and M are connected together in the rear. So if I run into an OBD1 vehicle with no contact in E... I just need to have a temporary jumper with spade end for M and a connector with lock removed to push in slot E from the rear?

On second thought..may just be easier to make a plug in adapter with an extra ALDL connector.

[steveo]

E and M in most off-the-shelf aldl cables are just connected together inside anyway; since baud rate is selected at the usb or serial driver.

this is why a 'bare' aldl cable is very useful, works with anything, including '95 obd1.5 mutants and chopped up hotrod swaps with no real aldl connector at all.

[Six_Shooter]

There are several combinations of pins used over the years of OBD1.