fendermender

I has been mentioned to me that the 94 Vettes don't have the OBD port. I have been considering a 94 at present. How much of a concern is this?
Thanks, Jim

zr1fred

It's all set up for OBD2, computer and connector. It has OBD1 logic/programing in it. Thats why they call the 94-95s hybrid systems. No, you can't upgrade it to OBD2. Most code readers won't read it. (some expensive ones do). You can read it manually. It's not normally a big problem, unless you have a problem.

Kmcoldcars

None. As I recall, the 1994 Vette has an OBD I port. It you really feel the need to hook up a scanner to the car you can buy scanners that will do OBD I.

zr1fred

No, it uses the OBD2 port.

fendermender

Guy next door does emmission testing. I'll see if his machine reads them.
Like you say Fred, without a problem I supose it doesn't matter.

Kmcoldcars

From information gathered on the web.

OBD-1.5OBD 1.5 refers to a partial implementation of OBD-II which General Motors used on some vehicles in 1994 and 1995 (GM did not use the term OBD 1.5 in the documentation for these vehicles - they simply have an OBD and an OBD-II section in the service manual.)

For example, the 94-95 Corvettes have one post-catalyst oxygen sensor (although they have two catalytic converters), and have a subset of the OBD-II codes implemented. For a 1994 Corvette the implemented OBD-II codes are P0116-P0118, P0131-P0135, P0151-P0155, P0158, P0160-P0161, P0171-P0175, P0420, P1114-P1115, P1133, P1153 and P1158.[3]

This hybrid system was present on the GM H-body cars in 94-95, W-body cars (Buick Regal, 94 Buick LeSabre, Chevrolet Lumina ('95 only), Chevrolet Monte Carlo ('95 only), Pontiac Grand Prix, Oldsmobile Cutlass Supreme) in 94-95, L-body (Chevrolet Beretta/Corsica) in 94-95, Y-body (Chevrolet Corvette) in 94-95, on the F-body (Chevrolet Camaro and Pontiac Firebird) in 95 and on the J-Body (Chevrolet Cavalier and Pontiac Sunfire) and N-Body (Buick Skylark, Oldsmobile Achieva, Pontiac Grand Am) in 95.

The pinout for the ALDL connection on these cars is as follows:


Female OBD connector pinout1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16

For ALDL connections, pin 9 is the data stream, pins 4 and 5 are ground and pin 16 is battery voltage.

An OBD 1.5 compatible scan tool is required to read codes generated by OBD 1.5.

Additional vehicle-specific diagnostic and control circuits are also available on this connector. For instance, on the Corvette there are interfaces for the Class 2 serial data stream from the PCM, the CCM diagnostic terminal, the radio data stream, the airbag system, the selective ride control system, the low tire pressure warning system and the passive keyless entry system.[4]