I posted this question a few days ago.whether my 94 Vette was OBDI or II.Some responded and said I would know by looking at my VECI label on the left side of the radiator.I looked and this label does not tell me which my car is.I know only a few had the OBDII in 94,but mine was made late in 94,that is why I am trying to see which one mine is.

 

94 is ALL OBD I

There are no OBD II 94's.

 

I've seen the replies saying some '94s had OBD II and I say The only way this could happen would be if a test car somehow snuck out into the public's hands. OBD II was still being developed in '94. Do they have some of the hardware? Yes, they have the 16 pin connector and they have one extra O2 sensor. However, true OBD II has 2 extra O2 sensors, one per cat. They're used to verify catalytic converter operation. A Federal Requirement of OBD II is misfire detection. In the case of the only OBD II equipped C4s produced, the 1996s, misfire detection required the addition of a crankshaft position sensor located in the bottom of the front (timing chain) cover. No 1994s have this sensor or even have the provision in the timing cover to install one unless someone added a '96 front cover (vs a '95) when converting to a later style Opti. There are other requirements as well such that '94s simply aren't equipped with the necessary hardware to even be easily retrofitted.

Although I have not disected the '94 PCM code, I'm told that it contains some elements of the OBD II strategy for field testing purposes. I would imagine this is primarily tied to the added o2 sensor.

Lastly, OBD II powertrain codes are Pxxxx where "xxxx" is a number such as 0300 or P0300 when displayed using a scan tool and you can't use the "paperclip trick" to display them since they're too long to display on the speedo. The OBD I codes are H (history)xxx or C(current)xxx where xxx is a number such as H031.

 

It's OBD I and be glad.

 

GM start OBDII in 1996 model year. Without a doubt your is OBDI

 

for those of you who are interested, here's some some "light" reading:

http://www.arb.ca.gov/msprog/obdprog/obdprog.htm

not to nitpick, but OBD-II is actually a California (CARB) requirement, while the Feds just call it plain ol' OBD. their requirements differ only slightly.

Jim is right on with his explanation of the 94 Corvette being OBD-I. there are probably shades of OBD-II features in pre-96 vehicles due to the fact it didn't make sense for GM to wait for the 11th hour to develop and introduce the newly required diagnostics. some of these diagnostic algorithms are not trivial to develop.

 

I believe that the confusion here arises because GM, in its infinite "wisdom" put OBD-II style connectors on some of their cars in late 1994 and 1995 even though they were OBD-I compliant...
Sort of like mixing metric and english fasteners on their cars....
The "bean counters" like to keep us guessing...

 

Yes 1995's have the OBDII equipment, but its not functional. The extra O2 sensors are dummies.