OBD1 vs OBD2
Thread Starter
Instructor
Joined: Sep 2010
Posts: 103
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From: Florissant Missouri
OBD1 vs OBD2
I have a 94 LTI Vette. As you all know, the 94 has an OBD1 ECM but was equipped with an OBD2 diagnostic connector. I was wondering if it is possible to replace the OBD1 ECM with a later model OBD2 ECM and what would be involved in the conversion?
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,008
From: Texas
You would need the added 02 sensor and Crankshaft Position Sensor (CPS) as well as the associated wiring and connectors. To add the CPS you need a new front engine cover. When you add the new front engine cover, you will need to purchase a new '95/'96 style Opti. With the new Opti you need to add the vent system. Of course you still have to address communications with the CCM and associated re-wiring.
It would be quicker and cheaper to sell the '94 and buy a '96.
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
Seems like many with 96 cars switch back the other way for ease of tuning, assuming emission laws don't play a part, The only gains from going to OBDII is misfire detection and cat condition monitor. From what I see from posts here the misfire detection on the 96 is crude at best, perhaps because it was the first attempt. Just seems like a lot of effort for little gain to me.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Sure. Like anything else it's a function of time and money.
You would need the added 02 sensor and Crankshaft Position Sensor (CPS) as well as the associated wiring and connectors. To add the CPS you need a new front engine cover. When you add the new front engine cover, you will need to purchase a new '95/'96 style Opti. With the new Opti you need to add the vent system. Of course you still have to address communications with the CCM and associated re-wiring.
It would be quicker and cheaper to sell the '94 and buy a '96.
You would need the added 02 sensor and Crankshaft Position Sensor (CPS) as well as the associated wiring and connectors. To add the CPS you need a new front engine cover. When you add the new front engine cover, you will need to purchase a new '95/'96 style Opti. With the new Opti you need to add the vent system. Of course you still have to address communications with the CCM and associated re-wiring.
It would be quicker and cheaper to sell the '94 and buy a '96.
with all the other postsPlus you would be giving up the on board diagnostics which works great on all the modules and you can invoke actions on systems but would need the FSM to know how to do that which most don't know about.
Melting Slicks
Joined: Jun 1999
Posts: 2,949
Likes: 23
From: Bowling Green KY
If you plan on keeping the car indefinitely and you are just dying to do it, then go right ahead.
But if you ever plan on selling the car or modding it, OBD I is much more preferable.
My car is a 96' but was converted (thankfully) to OBD I before I bought it. But I like hacking/modding/playing with things so I like the OBD I a LOT better.
I think you will find it's probably not worth it - as stated above you will need a new PCM, harness, connectors, also probably a new CCM to make everything work right, otherwise you will get a blinking "SYS" light on your dash because the CCM recognizes the PCM is not the right year, think it's a Code 81 if I am not mistaken (my 96 still had the 96 CCM and I had this issue).
But if you ever plan on selling the car or modding it, OBD I is much more preferable.
My car is a 96' but was converted (thankfully) to OBD I before I bought it. But I like hacking/modding/playing with things so I like the OBD I a LOT better.
I think you will find it's probably not worth it - as stated above you will need a new PCM, harness, connectors, also probably a new CCM to make everything work right, otherwise you will get a blinking "SYS" light on your dash because the CCM recognizes the PCM is not the right year, think it's a Code 81 if I am not mistaken (my 96 still had the 96 CCM and I had this issue).
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Thread Starter
Instructor
Joined: Sep 2010
Posts: 103
Likes: 0
From: Florissant Missouri
Thanks for the comments guys. I'll leave it OBD1. I'll admit I'm a newbie where working on computer equipped cars is concerned. One reason why I thought about making the conversion is that there seems to be a lot more and better scanners out there for OBD2 cars (not to mention that the only decent OBD1 scanner I've found is the GM Tech II and it's around $1500). I don't have a laptop so using one of the scanning software programs isn't really an option for me. Also, although they might work great for tuners, I really just want something for code scanning and maybe some data logging. Any suggestions that won't cost me an arm AND a leg? I hate to sound cheap, but I'm retired and money doesn't grow on trees for a retiree. PS I'm aware of the paper clip method of code retrieval but there has to be a better way than counting flashes of a light on the dash doesn't there?
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,008
From: Texas
Thanks for the comments guys. I'll leave it OBD1. I'll admit I'm a newbie where working on computer equipped cars is concerned. One reason why I thought about making the conversion is that there seems to be a lot more and better scanners out there for OBD2 cars (not to mention that the only decent OBD1 scanner I've found is the GM Tech II and it's around $1500). I don't have a laptop so using one of the scanning software programs isn't really an option for me. Also, although they might work great for tuners, I really just want something for code scanning and maybe some data logging. Any suggestions that won't cost me an arm AND a leg? I hate to sound cheap, but I'm retired and money doesn't grow on trees for a retiree. PS I'm aware of the paper clip method of code retrieval but there has to be a better way than counting flashes of a light on the dash doesn't there?
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Buy a used laptop with Windows 98 or Windows XP for $200 off of eBay and then go buy something like Datamaster for $100.
And this is one good way to go.But just to add your thinking earlier 90s GM cars counting flashes as I have had a 90 firebird. But I don’t believe you are familiar with the on board system for code retrieval. There are no lights. Each module (CCM, PCM, Brake, SIR) system has its own designated module number and specific set of specific codes. It is displayed in the speedometer area as the read out.
There is lots of info on the Forum and the internet on it. But I will say that the FSM is the best information for facts and how to do it. Plus there is additional info you will not find on the internet. But you can get all the info on getting the codes on the internet.
