OBD-I vs: OBD-II
Team Owner
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From: Riverside County Southern California
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Advanced
Joined: Dec 2010
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Hi all, and sorry to resurrect this thread but I'm curious about this. The 1994 and 1995 models both used a PCM, and I'm wondering, is what you say about the '95 model also true for the '94? If not, do you know of the major differences?
Le Mans Master
Joined: Jan 2006
Posts: 5,621
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From: Orlando FL
Bt let me just add that if you connect a 16 pin OBD2 code reader the try to see the OBD2 codes on my 94 (or 95), it will not even communicate (which is a given). But when I connect my Tech1 and look at the DTC codes (for OBD1), after it shows me the codes it goes to OBD2 codes. It always says "no OBD2 codes". So never having an OBD2 code, I really don’t know if it is actually working properly, or it always says that regardless all the time. I hope to really never have a OBD2 code which would make me real happy.
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Racer
Joined: Sep 2003
Posts: 275
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From: West Monroe La.
The same code scanner that works on my 1997 chev pu also works on my 95 corvette. It will communicate with the car as to codes or engine information. The plug is the same. I can scan the engine functions and recieve trouble codes on it, both the code and a brief description.
This scanner also works with my 05 Ford pu. I don't know a whole lot about obd1 or obd11, but I do know this actron scanner works on my car.
This scanner also works with my 05 Ford pu. I don't know a whole lot about obd1 or obd11, but I do know this actron scanner works on my car.
Advanced
Joined: Dec 2010
Posts: 60
Likes: 3
Thank you all for the replies. So here's my next question, if the setup for OBD II was technically "there" in the '94-'95 models, could switching to a true OBD II PCM really be as simple as getting a PCM from a '96, then getting a calibration flashed (say from '96 again) and installing it in the vehicle?
Race Director
Joined: Jan 2002
Posts: 12,263
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From: O'Fallon Missouri
The 1996 OBDII PCM monitors the crank position and rear o2 sensors. These could be tuned out, but I really see no reason to run an OBDII PCM in a 94/95. I'm not sure but the PCM and CCM may also have issues communicating.
Advanced
Joined: Dec 2010
Posts: 60
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Thanks for the info! I was just thinking about the "true" OBD II and was wondering if it would offer any perks as far as drivability and easier diagnostics.
Burning Brakes
Joined: Sep 2010
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http://www.amazon.com/Automotive-Dia.../dp/0760328005
This is a good book that describes the difference between OBD-I and OBD-II systems and gives great advice in the use of code reader and scan tools. I learned quite a bit about the function of emissions systems and how to troublrshoot and repair them from this publication.
This is a good book that describes the difference between OBD-I and OBD-II systems and gives great advice in the use of code reader and scan tools. I learned quite a bit about the function of emissions systems and how to troublrshoot and repair them from this publication.
