woody3882

I have a 1994 LT1 corvette. I read that the OBD technology changed in the middle of production for the 94 vette. I also read that my 94 has the OBD-1 connector but uses an OBD-2 technology.
I am going to buy an OBD scanner. Do I buy the OBD-1 or the OBD-2 ? is there an interchangeable adapter for the connection port ? Please enlighten me.
ALSO what is a reasonably priced scanner that could be recommended for the 94. I do not need a top end scanner, I do not own a business that will be using it everyday. I am just a 66 year old car-guy trying to do the best I can.

Thanks
Woody

blue94

OBD-2 is only in the 96, while the plug on 94 and 95 are OBD-2 they use an OBD-1 system

joeld

There are lots of scan tools out there, I only have experience with Actron. I use a CP9145 for OBD II cars. For the OBD I cars I use the same tool but use the adaptor cable CP9127. This also works for me on the mixed years 94/95 where there is a OBDII connector with OBDI ECM.

I have not used this tool on a 94/95 Corvette, but on several other GM cars such as Buicks, Oldsmobile etc.

Not sure if this scan tool is even being sold anymore by Actron, I think Amazon has them. I bought mine 20 years ago and has been a good tool for my purpose.

Joel

pcolt94

I use a Tech1 with a mass storage cartage but have all the individual ones. Have all the proper cables and adaptors also. Don’t know if they can still be had, great tool for the vette. Has bi-directional control as well. Might take a while to find one if you interested. All are not the same but you safe with a GM mass storage cartage. You might need the OBD connector for the OBD2 connector used.

MatthewMiller

That's backwards. Like blue94 wrote, your car has the newer 16-pin OBD2 connector but still used OBD1 in the ECM. Only the 96 C4 had an actual OBD2 ECM and equipment in place. Keep in mind that even with the newer connector, you can still pull codes without any tools other than a paper clip to short pin 12 to pin 4. It will give you all the codes from the Engine Control Module, Central Control Module, ABS/ASR module, and the Real Time Damping module (if your car has that feature). So if all you need is the DTCs, you don't really need a scanner.

woody3882

Thanks for the advise, I was just reading up on the "paper clip" trick. I also found that the internet is very user friendly for defining codes.. I was a bit leery of shoving a paper clip into the connectors, but it is very easy to do..
Thanks, all worked out well
Woody

antfarmer2

Just be sure you pull it before starting.

pcolt94

But I think I might have an idea what woody3882 is talking about. There are some OBD2 functions imbedded as well. They will not show up using the on board diagnosis and possibly not with other generic OBD1 scanners. But with my Tech1 when looking at the DTCs, only OBD1 codes show up. However there is another area that will show you the OBD2 codes if any.

It was for GM in gearing up for OBD2 in 96. But even if there is a OBD2 code, I don’t believe it does anything or gives any indication to the driver with lights or such. Seems like it's just a pre-test and a basic don’t care for normal operation.

MatthewMiller

I recall reading something similar. Any OBD2 codes shouldn't cause a dash light or failed inspection, as you note.

GaryDoug

This scanner will work for the 94/95 LT1. It is selling for only about $64 right now on Amazon. Can't beat that price. But he will need the CP9127 for about $30 extra.

anesthes

I also have a '94

I have an OBD1 USB cable.

http://obd2allinone.com/products/aldlobd2u.asp

$EE hack is a fantastic program for diagnostics, code clearing, etc.

http://fbodytech.com/eehack-2/

I tune the ECM with Tunercat, but free tunerpro works too.

I lowered my fan temps, disabled smog, etc.


-- Joe

woody3882

Joe, Thanks that is what i was looking for
Woody

Lazy Tom

This is what I want to do.
I just use the paper clip to get and clear codes.
Now I want a cable and software.

anesthes

Heh, I remember back in the 90s when we had to solder our own ALDL cables. Man has things got easy!

This is the only car I still use stock ECU's on, and if it wasn't for the integration with the CCM/dash, I'd swap the ECU for a Megasquirt.

But it's not terrible, at least it's flash based, and it's fairly configurable.

-- Joe