bwallace2

Does anyone know how to read an OBD 1.5. I thought i had the ODB-II, but think it is the OBD 1.5. I have a 94 coupe with a 16-pin connector. I took it to autozone and orielly's and neither could read it at all. I took the car to the chevy dealer for other work and they read it fine they said.

Red Dwarf

You shud be OBD I. I've never heard of I.5.

My 95 is OBD I with some OBD II parameters. It was just prior to the changeover to OBD II & they wanted to test some functions I guess?

Didn't the dealer tell you which you have? I feel quite sure you are OBD I.

toptechx6

See link

http://www.corvettephotographs.com/c4vettes/codes.htm

C4forlife

only 96 and up have obd 2. Even at that though you could swap back to a 95 ecm with only replacing the rear oxygen sensors.

PLRX

You can use a clip and connect ports 4 & 12

pcolt94

Absolutely right. The 94-95 have OBD2 connectors but you have to test with OBD1 unit. The software and protocol is OBD1 and if you connect a OBD2 unit to it will not establish communications.

A/Z sees that big old connector and goes right for the OBD2 scanner mainly because of lack of in depth knowledge.

Also on board diagnostics will not show any OBD2 embedded codes if one is set. It can only be seen with something like a Tech1 unit which was designed for GM dealers.

Best thing to do is use on board diagnostics as described above. It will tell you all you need to know

LT1 Spirit

[QUOTE=pcolt94;1565891968]Absolutely right. The 94-95 have OBD2 connectors but you have to test with OBD1 unit. The software and protocol is OBD1 and if you connect a OBD2 unit to it will not establish communications.

A/Z sees that big old connector and goes right for the OBD2 scanner mainly because of lack of in depth knowledge.

Also on board diagnostics will not show any OBD2 embedded codes if one is set. It can only be seen with something like a Tech1 unit which was designed for GM dealers.

I dont know about the 94 but I can get a connection with an OBDII scanner on my 95 and read codes that have been set. It also shows engine info while it is running. Im sure I can not see everything that is going on, but it does show a good bit of information from rpm's to O2 activity.

pcolt94

That is sure interesting information. Would sure like to hear if anyone else has had same success as you. Perhaps your scanner is better that the $100 or less ones that are bought in the local part stores. But protocol is protocol an don’t know why a better one would work differently even though it might have more features.

I believe the 95 is a bit more OBD2 advanced that the 94. But was not aware that it could establish OBD2 communications, maybe it’s different. Anyway would sure like to here more from others on this.

Eddie & the Cruisers

Some (most) OBD II scanners can read OBD I computers through the OBD II connector. They cost more than $100 though, more like $300.

Actron is one. They have adapters to use on older 12 pin connectors that need external power.