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Calling all pro obd1 tuner experts... I found something interesting!

PTO settings ( I think this is the high idle switch )
1633735928491.png

Governor settings
1633736039310.png

Idle settings
1633736102062.png

Startup settings
1633736193662.png

1633736261835.png

1633736314143.png

1633736354921.png

there are 80 DTC status flags in there that can be turned on and off. they were too large to do a screenshot on, but it lists all the DTC codes available each with a check box. some are set some are not. I have not played with any of them to know but I think it's simply a check box that when checked and the PCM sets that code, the SES light will turn on in the dash.

Well that sums up 99% of it. thats a lot of $hit for an obd1 system!!
 
I have read on other forums where some were trying to get that to work! not sure if it was successful but it seems it would be easy to do by just lowering the speed setting in the chart. being a 93 yours is probably a DB2 setup just guessing with a stand alone trans controller. I still have lots to learn, just getting started trying to teach myself all this stuff. if I can get my hands on a prom bin for that model I would be willing to try. lol but I wouldn't charge anything.

I do have a few prom bins that I have found online but have not played with any of them. not sure if they are all stock ether. here is a list of them I have so far. maybe someone can recognize the prom id's as to what year trucks and options they have, manual/auto trans, EGR, and such...

BHDF
BJDR
BJKW
BJKZ
BMRM
BNTB
BNTK
BPAA
BPDP
 
I don't know the PROM code on the chip, and I'm not going out there and unloading all the stuff packed into the cab to get into the glovebox and pull the ECM to access it to look, but my '94 C&C C2500HD Cheyenne has a speed limiter programmed into it for 82mph. This was the new ECM that was ordered back in 2001 when the transmission was being rebuilt and had to be special ordered from GM as no dealerships in a four-state region - that included Kansas City, St. Louis, Denver, Wichita and Des Moines - had it as it was a rare ECM PN. and the old one also limited me at 82 mph. The motor felt like it would just defuel/deboost when I hit 82mph.

Could this be what you're seeing in the tables for that '94 PROM you're reading, @dbrannon79 ? I'm like @Will L. , that computer coding and reading stuff is for my eldest son. Yes, Will, what you propose is intriguing as DS4 parts become NLA, converting over to a DB2 and doing either a rewrite on a PROM or a reflash of an OBD-II ECM to pretend that the IP is no longer there, but to control the transmission.
 
Husker6.5 said:
I don't know the PROM code on the chip, and I'm not going out there and unloading all the stuff packed into the cab to get into the glovebox and pull the ECM to access it to look, but my '94 C&C C2500HD Cheyenne has a speed limiter programmed into it for 82mph. This was the new ECM that was ordered back in 2001 when the transmission was being rebuilt and had to be special ordered from GM as no dealerships in a four-state region - that included Kansas City, St. Louis, Denver, Wichita and Des Moines - had it as it was a rare ECM PN. and the old one also limited me at 82 mph. The motor felt like it would just defuel/deboost when I hit 82mph.

Could this be what you're seeing in the tables for that '94 PROM you're reading, @dbrannon79 ? I'm like @Will L. , that computer coding and reading stuff is for my eldest son. Yes, Will, what you propose is intriguing as DS4 parts become NLA, converting over to a DB2 and doing either a rewrite on a PROM or a reflash of an OBD-II ECM to pretend that the IP is no longer there, but to control the transmission.
Click to expand...
It's possible, would you have your old PCM by chance? if you do would it still have the prom inside?

but to eliminate the 82mph limit I know that we could burn a new prom using the 95 BPAA which I have tested, plug that into your current PCM and it should run as a stock truck with no speed limiting. the only thing that makes me curious is since yours required a special one has me thinking that you might have a unicorn IP that might require special programming from GM. to know the answer to that one would be to check the tag thats on your IP and see if the part number is something abnormal. I think Will, WW or AK would know if you have the special IP by seeing the part number from the tag.
 
No, I have no clue what the transmission shop did with the Code 52 dead ECM, probably tossed it, that was nearly 20 years ago! And since the '94 was torn down in early 2006 for the two cracked heads it sustained - and is still awaiting me to put the two brand new complete heads I bought in 2007 on and put it back together, which is at the very bottom of my To Do List for the foreseeable future - I really have no need for any of that, but thanks for the offer, @dbrannon79. Besides, the 82mph limiter was actually a good thing as the Cheyenne is a Base Model and has no cruise control, so out on the Interstate I just kept the go pedal mashed to the floor and I never exceeded the State Patrol's 7mph 'cushion' for pulling over speeders!
 
No, @dbrannon79, mine did NOT require the 'special' IP. It's a C2500 HD in a C&C factory configuration designed for dealer/aftermarket upfitting with a utility box or flatbed. It is NOT the 3500HD that DID take the 'special' IP that year only.
 
Somebody on here quite a while back tried arguing that it was impossible and that there was no such thing as a C2500HD, only 3500HDs, until @Will L. chimed in and set them straight that in a past life as an upfitter, that he had seen such critters as a Cab & Chassis C2500HD from the factory. They were out there, but rare as can be. Mine has a Rawson Koenig box on it, the Mercedes Benz of utility boxes!
 
Will L. said:
82mph limiter is probably a smart thing hummers should have had! I don’t mind driving on the edge and a hummer over 90mph is there! Haha
Click to expand...
I can remember back in '96, at the NTC, taking Military M998's (6.2 NA) on I-15 from Yermo down to the old George AFB by Barstow and pretty much staying with traffic at 75-80, sometimes a little faster. Military speedometer and all, ya know. The soft top flapping at that speed? DEAFENING, @Will L.! That was on the Goodyear Military run-flats, too!
 
I ran into some luck! I found a TCM prom file online for our trucks. its from a GM TCM part number 16147609 prom code BACX from a 92 – 93 C/K Diesel L65, 4L80E Trans. all I need now is a $D3 xdf definition file to read it in tunerpro.

the search continues....
 
ok adding to the library... I found three TCM bin files and the xdf definition file for them. I opened one in tunerpro and I can see all the tables. the only thing is I don't know what engine they were for, it seems that they are all for 8 cylinder gas trucks all with 4l80e trans.
I have the TCM part numbers they work in and the prom numbers, so this might be a start. from what I am reading on the moates site, most of the TCM's are interchangeable in lots of trucks regardless of the engine.

here are the TCM part numbers and the prom id numbers I found...
16197427, 16196395, 16156930, 16168625
BHDF, BJDR, BMHK

I need to find a place to store these files online so anyone can access them that has an interest in them.

here is a screenshot of one of them..
1633751184555.png
 
The special IP that is being referred to is a 5068 and it used a different program in the PCM than all other years. When swapping to a different more standard IP you had to change the programming too. It was also used in lighter duty trucks than a 3500, my 94 3/4t parts truck had one in it
 
Man, you had a unicorn there with that 3/4 if it had a 5068 in it. It was my understanding from reading a lot of GM shop manuals (including the 1st Edition C/K Service Manual for pre-98 models) that it was only used on the 3500HDs. Was your 2500 an HD model, by chance, and an early 94 model run, before they shut down production to address the engine runaway problem?
 
@ak diesel driver do you still have that truck by chance? if you do, hang on to that PCM especially the prom chip. that thing is like gold along with the IP! when you have a chance look for the PCM number and the prom code. I would like to get the bin file for that one in my collection. it might save someone in the future!
 
ak diesel driver said:
Never paid much attention to the details like that. Aren't all 3/4t 6.5 considered hd? Not like the 3500 hd which had the taller front.
Click to expand...
No. The ¾T HD C&C had the 1Ton rear leaves in the springs and the SRW 1Ton's rear drums' wider shoes and wheel cylinders (at least that's what my mechanic told me when he did the rear brake job on it) and the front discs and calipers were 1T (when I put the drilled rotors on it, Power Stop emailed back and wanted the RPO number from the glove box after I'd given them the VIN to get the proper rotors) to compensate for the upfitting additional weight the optional rear 40 gallon Auxillary fuel tank (if equiped) a utility box or a flat bed with underhung tool boxes, or as I saw once a utility box with a 35' hydraulic boom bucket and to also maintain cargo carrying capacity at the same time. It rode a lot smoother when I had about 1500 lbs of building materials in the bed, vs. "empty" with just the utility bed with all the tools, etc., in the side compartments.
 
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