Distinguishing OBD1 from OBD2 PCM

I have two 1996 cars (1996 Caprice Classic and 1996 Fleetwood), both with PCM tunes that require premium fuel. With the upcharge for +91 octane now near $1.00 per gallon in NY, I'm thinking of having a detuned PCM on hand to allow use of 87 octane fuel until the situation changes, or in the event it gets even worse. (Yes, I'm aware that Sheetz sells 93 octane for +20 cents more south-of-the-border in PA, but in NY we vote to be raped after every election, and we're proud of it!).

Now, is there a part number generally stamped or otherwise marked on all PCMs that will definitively identify them as the part for an OBD2 car? I have found two part numbers online for the 1996 OBD2 PCM: GM 16214399, supposedly superceded by GM 88963801.

If you have one of these kicking around that needs a home, let me know via PM.

All PCMs for 96 my will be OBD2.

Rev Bob wrote:

All PCMs for 96 my will be OBD2.

Yes, mine too. But if you are handed a PCM and did not see the car it came from, is there generally a part number on the unit that would definitively identify it as having come from a 1996 (OBD2) vs a 94 or 95 (OBD1)?

Sorry. "my" in my post stands for model year. Any PCM stated as compatible with 1996 production will be OBD2.

dmg4 wrote:

I have two 1996 cars (1996 Caprice Classic and 1996 Fleetwood), both with PCM tunes that require premium fuel.   With the upcharge for +91 octane now near $1.00 per gallon in NY, I'm thinking of having a detuned PCM on hand to allow use of 87 octane fuel until the situation changes, or in the event it gets even worse. (Yes, I'm aware that Sheetz sells 93 octane for +20 cents more south-of-the-border in PA, but in NY we vote to be raped after every election, and we're proud of it!).

Now, is there a part number generally stamped or otherwise marked on all PCMs that will definitively identify them as the part for an OBD2 car?  I have found two part numbers online for the 1996 OBD2 PCM: GM 16214399, supposedly superceded by GM 88963801.  

If you have one of these kicking around that needs a home, let me know via PM.

hmmm.... for 20 bucks difference for a tank of fuel I wouldnt mess with anything. I'm guessing you aren't daily driving both of these... and if so, probably not putting tons and tons of miles on them to go through a bunch of fuel...

Quote :

hmmm.... for 20 bucks difference for a tank of fuel I wouldnt mess with anything.  I'm guessing you aren't daily driving both of these... and if so, probably not putting tons and tons of miles on them to go through a bunch of fuel...

Good advice if I didn't drive the two of them an average of 15,000 miles per year ($750  per year upcharge, for now).

I just want to know if a OBD2 PCM is marked with a part number that definitively identifies it.  Somebody?  Anybody?

I found manuals on 96 Fleetwood and Roadmaster and both state minimum 87 octane as is. They will detune themselves a bit as they learn the fuel so may ping a bit for while but should go away pretty quickly when it happens and happen less as it learns the fuel.

All you lose is a bit of performance. I have run it on occasion in my 96 RMW and it was not an issue at all.

Faaaaack! Guys.... go back to the top of the post and read the question.

dmg4 wrote:

Quote :

hmmm.... for 20 bucks difference for a tank of fuel I wouldnt mess with anything.  I'm guessing you aren't daily driving both of these... and if so, probably not putting tons and tons of miles on them to go through a bunch of fuel...

Good advice if I didn't drive the two of them an average of 15,000 miles per year ($750  per year upcharge, for now).

I just want to know if a OBD2 PCM is marked with a part number that definitively identifies it.  Somebody?  Anybody?

hmm... $750 for both? $375 for one? $31.25 a month.... ehhhhh.

Anyway,

not sure if this helps any, but I did find this online on an impala SS page.... besides checking for a sticker with the calibration VIN listed on it, then of course it would show you if its a 95/ older or 96 model.

94/95 OBD1 PCM that will work in our cars (once reprogrammed) is number 16188051
96 OBD2 PCM's are 16214399

booster wrote:

I found manuals on 96 Fleetwood and Roadmaster and both state minimum 87 octane as is.  They will detune themselves a bit as they learn the fuel so may ping a bit for while but should go away pretty quickly when it happens and happen less as it learns the fuel.

All you lose is a bit of performance.  I have run it on occasion in my 96 RMW and it was not an issue at all.

"As is" is correct but it doesn't pertain to his car because he has a PCM that was tuned for 93 octane and it will not "learn" anything if he runs 87, instead it will cause issues because of the custom tuning.

Who has a PCM in their hands that they know came out of a 1996 wagon? Just look and see if it has a part number on it. If that part number is 16214399 or 88963801, post here and then we can put this to bed.

I've one, but it's at the shop...I'll try to remember this weekend to snap some pictures of it and/or look for any part numbers.

Kinda surprised there isnt an old post with this info.. id head to ebay and start looking at used PCMs and note the part numbers in the pics

vivix wrote:

id head to ebay and start looking at used PCMs and note the part numbers in the pics

I did that before I started this thread.  I also searched the forum for the same information.  

The problem with just looking at the pics on eBay is that sellers seemed to use stock photos of one certain PCM to represent many different ones.  The resolution on other pics is just too pixelated to read.  Hence, this post.  I have  the correct GM part numbers for the 1996 OBD2 PCM.  That's not an issue.  They are already listed in this thread.  The OEM GM  part number is 16214399.  Some suppliers list 88963801 as the GM part number that superceded 16214399.

Again, my question is this: is this part number generally stuck on or stamped into the PCM?  If it is, and someone hands/sells me an old PCM, I can look at the part number and know it's correct.

Probably not any help, but part numbers starting in 889 are superseding numbers meant for a larger range of applications but that are identical to the parts superseded.

Might this help identify the part numbers?

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Fix Until Broke wrote:

Might this help identify the part numbers?

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Nope... but it did pull up one of the more interesting screens of the day.

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I had thought this might be straightforward: someone out there might have a spare out of the car kicking around that they could check, but think I just need to get one of my 1996 cars out of storage, and pull out the PCM and have a look for myself. I'll let you know what I find. This is a binary process. Either the PCM has a part number on the label or it doesn't.

Let's try asking the question differently: does anyone have a spare PCM that bears the magic number 16214399?

Picture of the sticker on the ECU of my 1996 Buick Roadmaster Wagon. No other obvious markings on it that I could see...

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It is from this website   [You must be registered and logged in to see this link.]

Wahoo!  Finally, a clue from the above chart from "Booster" and the previous picture of the sticker posted by "Fix Until Broke".  

The part number is on the PCM sticker, but the BSCR code identifies the PCM definitively as one from a 1996 Buick Roadmaster.

"Big Wagon Guy" has come through with a spare PCM.  I think we're done here.  Hopefully this thread proves useful to others in clarifying this issue.